path: root/doc/rfc/rfc3127.txt

Network Working Group                                          D. Mitton
Request for Comments: 3127                               Nortel Networks
Category: Informational                                      M. St.Johns
                                                  Rainmaker Technologies
                                                              S. Barkley
                                                                   UUNET
                                                               D. Nelson
                                                      Enterasys Networks
                                                                B. Patil
                                                                   Nokia
                                                              M. Stevens
                                                       Ellacoya Networks
                                                                B. Wolff
                                                            Databus Inc.
                                                               June 2001


             Authentication, Authorization, and Accounting:
                          Protocol Evaluation

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

Abstract

   This memo represents the process and findings of the Authentication,
   Authorization, and Accounting Working Group (AAA WG) panel evaluating
   protocols proposed against the AAA Network Access Requirements, RFC
   2989.  Due to time constraints of this report, this document is not
   as fully polished as it might have been desired.  But it remains
   mostly in this state to document the results as presented.













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Table of Contents

   1.  Process Description  . . . . . . . . . . . . . . . . . . . . . .3
   1.1  WG Co-Chair's Note  . . . . . . . . . . . . . . . . . . . . . .3
   1.2  Chairman's Note . . . . . . . . . . . . . . . . . . . . . . . .4
   1.3  Members Statements  . . . . . . . . . . . . . . . . . . . . . .4
   1.4  Requirements Validation Process . . . . . . . . . . . . . . . .6
   1.5  Proposal Evaluation . . . . . . . . . . . . . . . . . . . . . .7
   1.6  Final Recommendations Process . . . . . . . . . . . . . . . . .7
   2.  Protocol Proposals . . . . . . . . . . . . . . . . . . . . . . .8
   3.  Item Level Compliance Evaluation  . . . . . . . . . . . . . . . 8
   3.1  General Requirements . . . . . . . . . . . . . . . . . . . . . 9
   3.2  Authentication Requirements. . . . . . . . . . . . . . . . . .11
   3.3  Authorization Requirements . . . . . . . . . . . . . . . . . .12
   3.4  Accounting Requirements  . . . . . . . . . . . . . . . . . . .12
   3.5  MOBILE IP Requirements . . . . . . . . . . . . . . . . . . . .13
   4.  Protocol Evaluation Summaries . . . . . . . . . . . . . . . . .14
   4.1  SNMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
   4.2  Radius++ . . . . . . . . . . . . . . . . . . . . . . . . . . .14
   4.3  Diameter . . . . . . . . . . . . . . . . . . . . . . . . . . .14
   4.4  COPS . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14
   4.5  Summary Recommendation   . . . . . . . . . . . . . . . . . . .14
   5.  Security Considerations . . . . . . . . . . . . . . . . . . . .14
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . . .15
   7.  Authors' Addresses. . . . . . . . . . . . . . . . . . . . . . .15
   A.  Appendix A - Summary Evaluations  . . . . . . . . . . . . . . .17
   B.  Appendix B - Review of the Requirements . . . . . . . . . . . .18
   B.1 General Requirements. . . . . . . . . . . . . . . . . . . . . .18
   B.2 Authentication Requirements . . . . . . . . . . . . . . . . . .19
   B.3 Authorization Requirements. . . . . . . . . . . . . . . . . . .19
   B.4 Accounting Requirements . . . . . . . . . . . . . . . . . . . .20
   C.  Appendix C - Position Briefs  . . . . . . . . . . . . . . . . .21
   C.1  SNMP PRO Evaluation  . . . . . . . . . . . . . . . . . . . . .21
   C.2  SNMP CON Evaluation  . . . . . . . . . . . . . . . . . . . . .28
   C.3  RADIUS+ PRO Evaluation . . . . . . . . . . . . . . . . . . . .33
   C.4  RADIUS+ CON Evaluation . . . . . . . . . . . . . . . . . . . .37
   C.5  Diameter PRO Evaluation  . . . . . . . . . . . . . . . . . . .44
   C.6  Diameter CON Evaluation  . . . . . . . . . . . . . . . . . . .50
   C.7  COPS PRO Evaluation  . . . . . . . . . . . . . . . . . . . . .55
   C.8  COPS CON Evaluation  . . . . . . . . . . . . . . . . . . . . .59
   D.  Appendix D - Meeting Notes  . . . . . . . . . . . . . . . . . .66
   D.1  Minutes of 22-Jun-2000 Teleconference  . . . . . . . . . . . .66
   D.2  Minutes of 27-Jun-2000 Teleconference  . . . . . . . . . . . .68
   D.3  Minutes of 29-Jun-2000 Teleconference  . . . . . . . . . . . .73
   D.4  Minutes of 06-Jul-2000 Teleconference  . . . . . . . . . . . .78
   D.5  Minutes of 11-Jul-2000 Teleconference  . . . . . . . . . . . .80
   Full Copyright Statement  . . . . . . . . . . . . . . . . . . . . .84




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1.  Process Description

   Due to time constraints, the original draft of this document was
   rushed to meet the publication deadline of the June 2000 Pittsburgh
   meeting.  Since the meeting has passed, we do not wish to
   substantially revise the findings within this document, so that we
   don't give the appearance of changing information after the
   presentation.  Only additional descriptions of the process,
   formatting, layout editing and errors of fact have been corrected in
   subsequent revisions.

1.1.  WG Co-Chair's Note:

   After the AAA WG re-charter was approved, and the Network Access
   Requirements document passed AAA WG Last Call, a Solicitation of
   Protocol Submissions was issued on 4/13/2000.  The Solicitation was
   sent to the AAA WG mailing list, as well as to other IETF WG mailing
   lists related to AAA, including NASREQ, Mobile IP, RAP, and SNMPv3.

   Submissions were solicited effective immediately.  Authors of
   candidate protocols were requested to notify the AAA WG chairs of
   their intent to submit a candidate protocol.  It was suggested that
   this notification be sent by May 1, 2000.

   Protocol submissions and compliance description documents were to be
   submitted in Internet Draft format by email to internet-
   drafts@ietf.org.  The deadline for submissions was June 1, 2000.  To
   be considered as a candidate, submissions needed to include an
   unqualified RFC 2026 statement, as described at:
   http://www.ietf.org/Sec10.txt

   In order to assist the AAA WG in evaluating the protocol submissions
   and compliance description documents, the AAA WG chairs then formed
   an evaluation team, which was announced on May 20, 2000.  The job of
   the team was be to put together an Internet Draft documenting their
   evaluation of the protocol submissions.  The goal is to have a first
   draft available prior to the July 14, 2000 submission deadline for
   IETF 48.

   In composing the evaluation draft, the evaluation team was asked to
   draw from the protocol specifications, the compliance descriptions,
   and other relevant documents, the Network Access Requirements
   document, RFC 2989.

   Mike St. Johns was asked to chair the evaluation team.  The chairs of
   WGs related to AAA were also invited to join the team.  These
   included Dave Mitton, co-chair of NASREQ WG, Basavaraj Patil, co-
   chair of Mobile IP WG, and Mark Stevens, co-chair of the RAP WG.



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   Additional members of the evaluation team were chosen to represent
   the interests of network operators as well as developers of AAA
   client and server software.

   As usual, the IESG advised the evaluation team.  IESG advisors
   included Randy Bush and Bert Wijnen, Directors of the Operations and
   Management Area.

1.2.  Chairman's Note:

   This document is the result of 6 weeks of intense work by the panel
   listed below.  Our mission was to evaluate the various AAA proposals
   and provide recommendations to the AAA working group and to the IESG
   on the viability of each of the proposals.

   The evaluation process had three distinct phases.  1) Validate the
   AAA requirements document [AAAReqts] against the base requirements
   documents for NASREQ, MOBILEIP and ROAMOPS.  2) Evaluate each of the
   SNMP, Radius++, Diameter and COPS proposal claims against the
   validated requirements.  3) Provide final recommendations based on
   side by side comparison for each proposal on a requirement by
   requirement basis.

   In general, the ONLY information the evaluators were allowed to use
   throughout the process was that provided in the source documents (the
   requirements document and the proposal) or documents referenced by
   the source documents.  In other words, if it wasn't written down, it
   generally didn't exist.  Our cutoff for acceptance of information was
   1 June 2000 - any submissions after that time were not considered in
   the panel's deliberations.

1.3.  Members Statements

   The group was chaired by Michael St.Johns.  David Mitton was the
   document editor.  Following are the background statements and any
   conflicts of interest from them and the rest of the panel.

   Michael St. Johns, Rainmaker Technologies

   I have no known conflicts of interest with respect to the AAA
   process.  I have neither advocated nor participated in the creation
   of any of the submissions.  My company is a service company (ISP) and
   will not be involved in the manufacture or sale  of AAA enabled
   products.  Other than my participation as the chair of the AAA
   evaluation process, I have not had any contact with the AAA standards
   process.





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   David Mitton, Nortel Networks

   I have been Nasreq WG co-chair and author of several Nasreq drafts.
   As well as, previously contributed to several RADIUS drafts.

   I have been a RADIUS NAS implementor and Technical Prime on our
   Server products, so know it extremely well.  In my current job role I
   am involved with Nortel's IP Mobility products, which support
   Diameter.

   I have written a presentation on COPS vs NASreq Requirements for a
   Nasreq meeting, but have not implemented it, nor consider myself an
   through expert on the subject.

   Stuart Barkley, UUNET

   I've been working for 5 years at UUNET on various parts of our dialup
   network.  I have extensive experience with designing, developing and
   operating our SNMP based usage data gathering system.  I've also been
   involved in our radius based authentication and authorization systems
   in an advisory position.

   I've participated in radius/roamops/nasreq/aaa groups for the past
   several years.  I'm not an author or contributer on any of the
   requirements or protocol documents being presented although I have
   been peripherally involved in these working groups.

   Dave Nelson, Enterasys Networks

   Very active in the RADIUS WG, especially during the early years.  No
   involvement in the AAA submission.  Have not contributed to the
   development of Diameter.

   No involvement with SNMPv3 or the AAA submission.  David Harrington,
   a proponent, works in a different group within my company.  We have
   not discussed the submission.  No involvement with the COPS protocol.

   Basavaraj Patil, Nokia

   I am a contributor to the AAA requirements document (RFC 2977)
   submitted by the Mobile IP WG.  I was a member of the team that was
   constituted to capture the Mobile IP requirements for AAA services.

   As part of the co-chairing activity of the Mobile IP WG I have
   realized the need for AAA services by Mobile IP and hence closely
   followed the work done in the AAA WG, RADIUS, RoamOps and TR45.6.





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   My present work at Nokia does involve looking at AAA protocols (to
   some extent at least) for use in wireless networks.  I have also done
   some work with AAA protocols such as Diameter in my previous job at
   Nortel Networks.

   Mark Stevens, Ellacoya Networks

   I am the co-chair of the IETF RAP working group which is the working
   group that has developed the COPS protocol.  I have not contributed
   to the documents describing how COPS can satisfy AAA requirements.

   I participated in early AAA working group meetings, but have not been
   an active participant since the group's rechartering.  The company
   that currently employees me builds devices might benefit from being
   AAA enabled.

   Barney Wolff, Databus Inc.

   I have implemented RADIUS client, proxy and server software, under
   contract to AT&T.  That software is owned by AT&T and I have no
   financial interest in it.

   I have been a member of the RADIUS WG for several years, and consider
   myself an advocate for RADIUS against what I consider unjustified
   attacks on it.

   I've never worked for any of the companies whose staff have produced
   any of the proposals, although I obviously might at some future time.

1.4.  Requirements Validation Process

   For each of the base requirements documents, the chair assigned a
   team member to re-validate the requirement.  The process was fairly
   mechanical; the evaluator looked at what was said in [AAAReqts], and
   verified that the references and supporting text in the basis
   document supported the requirement in [AAAReqts] as stated.  Where
   the reference was wrong, too general, missing or otherwise did not
   support the requirement, the evaluator either deleted or downgraded
   the requirement.  The results of that process were sent to the AAA
   mailing list and are also included in this document in the
   appendixes.  The group's used [AAAReqts] as modified by our
   validation findings to evaluate the AAA proposals.









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1.5.  Proposal Evaluation

   For each of the four proposals, the chair assigned two panel members
   to write evaluation briefs.  One member was assigned to write a 'PRO'
   brief and could take the most generous interpretation of the
   proposal; he could grant benefit of doubt.  The other member was
   assigned to write a 'CON' brief and was required to use the strictest
   criteria when doing his evaluation.

   Each brief looked at each individual requirement and evaluated how
   close the proposal came in meeting that requirement.  Each item was
   scored as one of an 'F' for failed to meet the requirement, 'P' for
   partially meeting the requirement, or 'T' for totally meeting the
   requirement.  The proposals were scored only on the information
   presented.  This means that a particular protocol might actually meet
   the specifics of a requirement, but if the proposal did not state,
   describe or reference how that requirement was met, in might be
   scored lower.

   The panel met by teleconference to discuss each proposal and the PRO
   and CON briefs.  Each of the briefers discussed the high points of
   the brief and gave his summary findings for the proposal.  We then
   discussed each individual requirement line-by-line as a group.  At
   the conclusion, the members provided their own line-by-line
   evaluations which were used to determine the consensus evaluation for
   the specific requirement relative to that proposal.  The meeting
   notes from those teleconferences as well as the individual briefs are
   included in the appendixes.

1.6.  Final Recommendations Process

   The panel met for one last time to compare the results for the four
   proposals and to ensure we'd used consistent evaluation criteria.  We
   did a requirement by requirement discussion, then a discussion of
   each of the protocols.

   The final phase was for each member to provide his final summary
   evaluation for each of the protocols.  Each proposal was scored as
   either Not Acceptable, Acceptable Only For Accounting, Acceptable
   with Engineering and Fully Acceptable.  Where a proposal was
   acceptable with engineering, the member indicated whether it would be
   a small, medium or large amount.

   It should be noted that score indicated the opinion of the team
   member.  And they may have taken into consideration background
   knowledge or additional issues not captured in the minutes presented
   here.




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   Each member's scores were used within the group to develop the
   group's consensus.

2.  Protocol Proposals

   The following proposal documents were submitted to the AAA WG for
   consideration by the deadline.

   - SNMP:

      [SNMPComp] "Comparison of SNMPv3 Against AAA Network Access
                  Requirements", Work in Progress.

   - RADIUS Enhancements:

      [RADComp]  "Comparison of RADIUS Against AAA Network Access
                  Requirements", Work in Progress.

      [RADExt]   "Framework for the extension of the RADIUS(v2)
                  protocol", Work in Progress.

   - Diameter

      [DIAComp]  "Comparison of Diameter Against AAA Network Access
                  Requirements", Work in Progress.

   - COPS for AAA:

      [COPSComp] "Comparison of COPS Against the AAA NA Requirements",
                  Work in Progress.

      [COPSAAA]  "COPS Usage for AAA", Work in Progress.

3.  Item Level Compliance Evaluation

   For each requirement item, the group reviewed the proposal's level of
   compliance.  Where the proposal was lacking, the evaluators may have
   made supposition on how hard it would be to resolve the problem.  The
   following shows the consensus results for each requirement item.

   Key:
   T = Total Compliance, Meets all requirements fully
   P = Partial Compliance, Meets some requirements
   F = Failed Compliance, Does not meet requirements acceptably

   Where two are shown eg: P/T, there was a tie.





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   The sub-section numbering corresponds to the requirements document
   section and item numbers.  This relative numbering was also used in
   the Protocol Position presentations, here in the appendices.

3.1 General Requirements

   3.1.1 Scalability - SNMP:P, RADIUS:P, Diameter:T, COPS:T

   SNMP was downgraded due to a lack of detail of how the current agent
   model would be adapted to a client request based transaction.  The
   RADIUS proposal did not address the problem adequately.  There are
   open issues in all proposals with respect to webs of proxies.

   3.1.2 Fail-over - SNMP:P, RADIUS:P, Diameter:P, COPS:T/P

   The group particularly noted that it didn't think any protocol did
   well in this requirement.  Insufficient work has been done to specify
   link failure detection and primary server recovery in most
   submissions.  COPS has some mechanisms but not all.  How these
   mechanisms would work in a web of proxies has not been addressed.

   3.1.3 Mutual Authentication  - SNMP:T, RADIUS:T/P, Diameter:T, COPS:T

   Many of the submissions missed the point of the requirement.  There
   should be a way for the peers to authenticate each other, end-to-end,
   or user-to-server.   However, the group questions who really needs
   this feature, and if it could be done at a different level.

   Mutual authentication in RADIUS is only between hops.

   3.1.4 Transmission Level Security  - SNMP:T, RADIUS:P, Diameter:T,
   COPS:T

   All protocols have methods of securing the message data.

   3.1.5 Data Object Confidentiality  - SNMP:P, RADIUS:P, Diameter:T,
   COPS:T

   This requirement usually comes from third-party situations, such as
   access outsourcing.

   Diameter and COPS both use CMS formats to secure data objects.  The
   group is concerned if this method and it's support is perhaps too
   heavy weight for NAS and some types of edge systems.







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   3.1.6 Data Object Integrity  - SNMP:F, RADIUS:P, Diameter:T, COPS:T

   How to guard the data object from changes was not adequately
   described in the SNMP proposal.  The RADIUS solution was not very
   strong either.

   3.1.7 Certificate Transport  - SNMP:T, RADIUS:T, Diameter:T, COPS:T

   All protocols can figure out some way to transport a certificate.

   3.1.8 Reliable AAA Transport  - SNMP:P, RADIUS:P, Diameter:T, COPS:T

   The requirement does not give a definition of "how reliable" it must
   be.

   The SNMP and RADIUS proposals lacked in providing solutions to
   message retransmission and recovery.

   3.1.9 Run over IPv4  - SNMP:T, RADIUS:T, Diameter:T, COPS:T

   3.1.10 Run over IPv6  - SNMP:P, RADIUS:T, Diameter:T, COPS:T

   The SNMP proposal indicated that this area is still in the
   experimental stages.

   3.1.11 Support Proxy and Routing Brokers  - SNMP:F, RADIUS:P,
   Diameter:T, COPS:P

   The SNMP proposal did not address this requirement.  COPS claims
   support, but does not work through some of the issues.  Diameter was
   the only protocol that attempted to address this area to a fair
   extent.

   3.1.12 Auditability - SNMP:F, RADIUS:F, Diameter:T, COPS:P

   We treated this requirement as something like "non-repudiation".
   There is a concern that digital signatures may be too computationally
   expensive for some equipment, and not well deployed on those
   platforms.

   The SNMP and RADIUS proposals did not attempt to work this
   requirement.  COPS suggests that a History PIB will help solve this
   problem but gives no description.








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   3.1.13 Shared Secret Not Required  - SNMP:P/T, RADIUS:T, Diameter:T,
   COPS:T

   The requirement is interpreted to mean that any application level
   security can be turned off in the presence of transport level
   security.

   Pretty much every protocol can use an enveloping secure transport
   that would allow them not to use an internal secret.

   3.1.14 Ability to Carry Service Specific Attributes  - SNMP:T,
   RADIUS:T, Diameter:T, COPS:T

3.2 Authentication Requirements

   3.2.1 NAI Support  - SNMP:T, RADIUS:T, Diameter:T, COPS:T

   3.2.2 CHAP Support  - SNMP:T, RADIUS:T, Diameter:T, COPS:T

   3.2.3 EAP Support  - SNMP:T, RADIUS:T, Diameter:T, COPS:T

   3.2.4 PAP/Clear-text Passwords  - SNMP:T, RADIUS:T, Diameter:T,
   COPS:T

   The requirement for clear-text passwords comes from one-time-password
   systems and hard-token (SecurID) systems.

   3.2.5 Reauthentication on demand - SNMP:T, RADIUS:P, Diameter:P,
   COPS:T

   To supply this, the proposal must have asynchronous peer-to-peer
   capabilities, and there must defined operation for such state
   changes.

   We also distinguished event-driven Reauthentication from timer-driven
   (or lifetime-driven).  Also concerned about how this would work in a
   proxy environment.

   3.2.6 Authorization w/o Authentication - SNMP:P, RADIUS:T/P,
   Diameter:T, COPS:T

   This requirement really means authorization with trivial
   authentications (e.g. by assertion or knowledge).








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3.3 Authorization Requirements

   3.3.1 Static and Dynamic IP Addr Assignment - SNMP:P/F, RADIUS:T,
   Diameter:T, COPS:T

   There is difficulty in interpreting what is static or dynamic with
   respect to the viewpoint of the client, server, administrator or
   user.

   3.3.2 RADIUS Gateway Capability  - SNMP:P, RADIUS:P, Diameter:T/P,
   COPS:P

   It was noted that any new capability in a new AAA protocol would not
   be able to map directly back to RADIUS.  But this is already a
   problem within a RADIUS environment.

   3.3.3 Reject Capability  - SNMP:T/P/F, RADIUS:T, Diameter:T, COPS:P

   3.3.4 Preclude Layer 2 Tunneling  - SNMP:F, RADIUS:T, Diameter:T,
   COPS:T

   3.3.5 Reauthorization on Demand  - SNMP:P/F, RADIUS:P, Diameter:T/P,
   COPS:T

   Some evaluators wondered how the server will know that re-
   authorization is supposed to be done?  Will it interface to something
   external, or have sufficient internals?

   3.3.6 Support for Access Rules & Filters  - SNMP:P, RADIUS:P,
   Diameter:P, COPS:T/P

   Only the Diameter proposal actually tackled this issue, but the group
   felt that the rules as designed were too weak to be useful.  There
   was also concern about standardizing syntax without defining
   semantics.

   3.3.7 State Reconciliation - SNMP:F, RADIUS:P/F, Diameter:P, COPS:T/P

   All of the protocols were weak to non-existent on specifying how this
   would be done in a web of proxies situation.

   3.3.8 Unsolicited Disconnect  - SNMP:T, RADIUS:P, Diameter:T, COPS:T

3.4 Accounting Requirements

   3.4.1 Real Time Accounting  - SNMP:T, RADIUS:T, Diameter:T, COPS:T





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   3.4.2 Mandatory Compact Encoding  - SNMP:T, RADIUS:T, Diameter:T,
   COPS:T

   3.4.3 Accounting Record Extensibility  - SNMP:T, RADIUS:T,
   Diameter:T, COPS:T

   3.4.4 Batch Accounting  - SNMP:T, RADIUS:F, Diameter:P, COPS:P

   Some members of the group are not sure how this fits into the rest of
   the AAA protocol, which is primarily real-time and event driven.
   Would this be better met with FTP?

   3.4.5 Guaranteed Delivery   - SNMP:T, RADIUS:T, Diameter:T, COPS:T

   3.4.6 Accounting Timestamps       - SNMP:T, RADIUS:T, Diameter:T,
   COPS:T

   3.4.7 Dynamic Accounting  - SNMP:T, RADIUS:T, Diameter:T, COPS:T

3.5 MOBILE IP Requirements

   3.5.1 Encoding of MOBILE IP Registration Messages  - SNMP:T,
   RADIUS:T/P, Diameter:T, COPS:T

   3.5.2 Firewall Friendly   - SNMP:F, RADIUS:T, Diameter:P, COPS:P

   There was considerable discussion about what it means to be "firewall
   friendly".  It was suggested that not making the firewall look into
   packets much beyond the application port number.  Protocols such as
   SNMP and COPS are at a disadvantage, as you must look far into the
   packet to understand the intended operation.  Diameter will have the
   disadvantage of SCTP, which is not well deployed or recognized at the
   moment.

   SNMP and COPS also have the problem that they are used for other
   types of operations than just AAA.

   Should firewalls have AAA Proxy engines?

   We didn't look at "NAT friendly" issues either.

   COPS:T

   The group is not clear on how this requirement impacts the actual
   protocol.  Raj explained it to us, but we mostly took it on faith.






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4.  Protocol Evaluation Summaries

4.1.  SNMP

   SNMP is generally not acceptable as a general AAA protocol.  There
   may be some utility in its use for accounting, but the amount of
   engineering to turn it into a viable A&A protocol argues against
   further consideration.

4.2.  Radius++

   Radius++ is not considered acceptable as an AAA protocol.  There is a
   fairly substantial amount of engineering required to make it meet all
   requirements, and that engineering would most likely result in
   something close to the functionality of Diameter.

4.3.  Diameter

   Diameter is considered acceptable as an AAA protocol.  There is some
   minor engineering required to bring it into complete compliance with
   the requirements but well within short term capabilities.  Diameter
   might also benefit from the inclusion of a broader data model ala
   COPS.

4.4.  COPS

   COPS is considered acceptable as an AAA protocol.  There is some
   minor to medium engineering required to bring it into complete
   compliance with the requirements.

4.5.  Summary Recommendation

   The panel expresses a slight preference for Diameter based on the
   perception that the work for Diameter is further along than for COPS.
   However, using SCTP as the transport mechanism for Diameter places
   SCTP on the critical path for Diameter.  This may ultimately result
   in COPS being a faster approach if SCTP is delayed in any way.

5.  Security Considerations

   AAA protocols enforce the security of access to the Internet.  The
   design of these protocols and this evaluation process took many
   security requirements as critical issues for evaluation.  A candidate
   protocol must meet the security requirements as documented, and must
   be engineered and reviewed properly as developed and deployed.






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6.  References

   [AAAReqts] Aboba, B., Clahoun, P., Glass, S., Hiller, T., McCann, P.,
              Shiino, H., Walsh, P., Zorn, G., Dommety, G., Perkins, C.,
              Patil, B., Mitton, D., Manning, S., Beadles, M., Chen, X.,
              Sivalingham, S., Hameed, A., Munson, M., Jacobs, S., Lim,
              B., Hirschman, B., Hsu, R., Koo, H., Lipford, M.,
              Campbell, E., Xu, Y., Baba, S. and E. Jaques, "Criteria
              for Evaluating AAA Protocols for Network Access", RFC
              2989, April 2000.

   [AAAComp]  Ekstein, TJoens, Sales and Paridaens, "AAA Protocols:
              Comparison between RADIUS, Diameter and COPS", Work in
              Progress.

   [SNMPComp] Natale, "Comparison of SNMPv3 Against AAA Network Access
              Requirements", Work in Progress.

   [RADComp]  TJoens and DeVries, "Comparison of RADIUS Against AAA
              Network Access Requirements", Work in Progress.

   [RADExt]   TJoens, Ekstein and DeVries, "Framework for the extension
              of the RADIUS (v2) protocol", Work in Progress,

   [DIAComp]  Calhoun, "Comparison of Diameter Against AAA Network
              Access Requirements", Work in Progress.

   [COPSComp] Khosravi, Durham and Walker, "Comparison of COPS Against
              the AAA NA Requirements", Work in Progress.

   [COPSAAA]  Durham, Khosravi, Weiss and Filename, "COPS Usage for
              AAA", Work in Progress.

7.  Authors' Addresses

   David Mitton
   Nortel Networks
   880 Technology Park Drive
   Billerica, MA 01821

   Phone: 978-288-4570
   EMail: dmitton@nortelnetworks.com









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   Michael StJohns
   Rainmaker Technologies
   19050 Pruneridge Ave, Suite 150
   Cupertino, CA 95014

   Phone: 408-861-9550 x5735
   EMail: stjohns@rainmakertechnologies.com

   Stuart Barkley
   UUNET
   F1-1-612
   22001 Loudoun County Parkway
   Ashburn, VA  20147  US

   Phone: 703-886-5645
   EMail: stuartb@uu.net

   David B. Nelson
   Enterasys Networks, Inc. (a Cabletron Systems company)
   50 Minuteman Road
   Andover, MA 01810-1008

   Phone: 978-684-1330
   EMail: dnelson@enterasys.com

   Basavaraj Patil
   Nokia
   6000 Connection Dr.
   Irving, TX 75039

   Phone: +1 972-894-6709
   EMail: Basavaraj.Patil@nokia.com

   Mark Stevens
   Ellacoya Networks
   7 Henry Clay Drive
   Merrimack, NH  03054

   Phone: 603-577-5544 ext. 325
   EMail: mstevens@ellacoya.com

   Barney Wolff, Pres.
   Databus Inc.
   15 Victor Drive
   Irvington, NY 10533-1919 USA

   Phone: 914-591-5677
   EMail: barney@databus.com



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Appendix A - Summary Evaluations Consensus Results by Requirement
             and Protocol

   Requirement Section         SNMP      Radius++  Diameter  COPS
           1.1.1                P         P         T         T
           1.1.2                P         P         P       T/P
           1.1.3                T       T/P         T         T
           1.1.4                T         P         T         T
           1.1.5                P         P         T         T
           1.1.6                F         P         T         T
           1.1.7                T         T         T         T
           1.1.8                P         P         T         T
           1.1.9                T         T         T         T
           1.1.10               P         T         T         T
           1.1.11               F         P         T         P
           1.1.12               F         F         T         P
           1.1.13             P/T         T         T         T
           1.1.14               T         T         T         T

           1.2.1                T         T         T         T
           1.2.2                T         T         T         T
           1.2.3                T         T         T         T
           1.2.4                T         T         T         T
           1.2.5                T         P         P         T
           1.2.6                P       T/P         T         T

           1.3.1              P/F         T         T         T
           1.3.2                P         T       T/P         P
           1.3.3            T/P/F         T         T         P
           1.3.4                F         T         T         T
           1.3.5              P/F         P       T/P         T
           1.3.6                P         P         P       T/P
           1.3.7                F       P/F         P       T/P
           1.3.8                T         P         T         T

           1.4.1                T         T         T         T
           1.4.2                T         T         T         T
           1.4.3                T         T         T         T
           1.4.4                T         F         P         P
           1.4.5                T         T         T         T
           1.4.6                T         T         T         T
           1.4.7                T         T         T         T

           1.5.1                T       T/P         T         T
           1.5.2                F         T         P         P
           1.5.3                F         P         T         T





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Appendix B - Review of the Requirements

   Comments from the Panel on then work in progress, "Criteria for
   Evaluating AAA Protocols for Network Access" now revised and
   published as RFC 2989.  This became the group standard interpretation
   of the requirements at the time.

B.1 General Requirements

   Scalability - In clarification [a], delete "and tens of thousands of
   simultaneous requests."  This does not appear to be supported by any
   of the three base documents.

   Transmission level security - [Table] Delete the ROAMOPS "M" and
   footnote "6".  This appears to be an over generalization of the
   roaming protocol requirement not necessarily applicable to AAA.

   Data object confidentiality - [Table] Delete the MOBILE IP "S" and
   footnote "33".  The base document text does not appear to support
   this requirement.

   Reliable AAA transport mechanism - In clarification [h] delete
   everything after the "...packet loss" and replace with a ".".  The
   requirements listed here are not necessarily supported by the base
   document and could be mistakenly taken as requirements for the AAA
   protocol in their entirety.

   Run over IPv4 - [Table] Replace the MOBILE IP footnote "17" with
   footnote "33".  This appears to be a incorrect reference.

   Run over IPv6 - [Table] Replace the MOBILE IP footnote "18" with a
   footnote pointing to section 8 of [8].  This appears to be an
   incorrect reference.

   Auditability - Clarification [j] does not appear to coincide with the
   NASREQ meaning of Auditability.  Given that NASREQ is the only
   protocol with an auditability requirement, this section should be
   aligned with that meaning.

   Shared secret not required - [Table] General - This section is
   misleadingly labeled.  Our team has chosen to interpret it as
   specified in clarification [k] rather than any of the possible
   interpretations of "shared secret not required".  We recommend the
   tag in the table be replaced with "Dual App and Transport Security
   Not Required" or something at least somewhat descriptive of [k].
   Delete the NASREQ "S" and footnote "28" as not supported by the
   NASREQ document.  Delete the MOBILE IP "O" and footnotes "34" and 39"
   as not supported.



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B.2 Authentication Requirements

   NAI Support - [Table] Replace MOBILE IP footnote "38" with "39".
   This appears to be a more appropriate reference.

   CHAP Support - [Table] Delete MOBILE IP "O" as unsupported.

   EAP Support - [Table] Delete MOBILE IP "O" as unsupported.

   PAP/Clear-Text Support - [Table] Replace NASREQ footnote "10" with
   "26" as being more appropriate.  Replace ROAMOPS "B" with "O".  The
   reference text appears to not explicitly ban this and specifically
   references clear text for OTP applications.  Delete MOBILE IP "O" as
   unsupported.

   Re-authentication on demand - Clarification [e] appears to go beyond
   the requirements in NASREQ and MOBILE IP.  [Table] Delete MOBILE IP
   footnote "30" as inapplicable.

   Authorization Only without Authentication - Clarification [f] does
   not include all NASREQ requirements, specifically that unneeded
   credentials MUST NOT be required to be filled in.  Given that there
   are no other base requirements (after deleting the MOBILE IP
   requirement) we recommend that clarification [f] be brought in line
   with NASREQ.  [Table] Delete MOBILE IP "O" and footnote "30".  The
   referenced text does not appear to support the requirement.

B.3 Authorization Requirements

   Static and Dynamic... - Clarification [a] appears to use a
   particularly strange definition of static and dynamic addressing.
   Recommend clarification here identifying who (e.g. client or server)
   thinks address is static/dynamic.  [Table] ROAMOPS "M" appears to be
   a derived requirement instead of directly called out.  The footnote
   "1" should be changed to "5" as being more appropriate.  A text
   clarification should be added to this document identifying the
   derived requirement.

   RADIUS Gateway capability - [Table] Delete the MOBILE IP "O" and
   footnote "30".  The referenced text does not appear to support the
   requirement.

   Reject capability - [Table] Delete the NASREQ "M" and footnote "12".
   The NASREQ document does not appear to require this capability.







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   Reauthorization on Demand - [Table] Delete the MOBILE IP "S" and
   footnotes "30,33" The referenced text does not support this
   requirement.

   Support for Access Rules... - Clarification [e] has a overbroad list
   of requirements.  NASREQ only requires 5-8 on the list, and as The
   MOBILE IP requirement is not supported by its references, this
   clarification should match NASREQ requirements.  [Table] Delete the
   MOBILE IP "O" and footnotes "30,37" as not supported.

   State Reconciliation - Clarification [f] should be brought in line
   with NASREQ requirements.  The clarification imposes overbroad
   requirements not required by NASREQ and NASREQ is the only service
   with requirements in this area.

B.4 Accounting Requirements

   Real-Time accounting - [Table] Replace MOBILE IP footnote [39] with a
   footnote pointing to section 3.1 of [3] as being more appropriate.

   Mandatory Compact Encoding - [Table] Delete MOBILE IP "M" and
   footnote "33" as the reference does not support the requirement.

   Accounting Record Extensibility - [Table] Delete NASREQ "M" and
   footnote "15" as the reference does not support the requirement.

   Accounting Time Stamps - [Table] Delete MOBILE IP "S" and footnote
   "30" as they don't support the requirement.  Replace MOBILE IP
   footnote "40" with a footnote pointing to section 3.1 of [3] as being
   more appropriate.

   Dynamic Accounting - [Table] Replace the NASREQ footnote "18" with a
   footnote pointing to section 8.4.1.5 of [3].  Delete the MOBILE IP
   "S" and footnote "30" as the reference does not support the
   requirement.

   Footnote section.

   [40] should be pointing to 6.1 of [4].
   [41] should be pointing to 6.2.2 of [4].
   [45] should be pointing to 6.4 of [4].
   [46] should be pointing to 8 of [4].









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Appendix C - Position Briefs

C.1 SNMP PRO Evaluation

   Evaluation of SNMP AAA Requirements
   PRO Evaluation
   Evaluator - Stuart Barkley

   Ref [1] is "Comparison of SNMPv3 Against AAA Network Access
   Requirements", aka 'the document'
   Ref [2] is the aaa eval criteria as modified by us, aka 'the
   requirements'

   The document uses T to indicate total compliance, P to indicate
   partial compliance and F to indicate no compliance.  For each section
   I've indicated my grade for the section.  If there is a change, I've
   indicated that and the grade given by the authors.

   1 Per item discussion

   1.1 General Requirements

   1.1.1 Scalability - Grade T

   The document indicates that SNMP can adequately handle that scale
   from the requirements document.  Since most current uses are ppp
   connections and SNMP is already capable of handling the interface
   table and other per session tables it is clear that basic capacity
   exists.  Additions to support other tables and variables scales in a
   simple linear fashion with the number of additional variables and
   protocol interactions.  Regardless of the final selected protocol
   handling the scaling required is not a trivial undertaking.  SNMP can
   draw upon existing network management practices to assist in this
   implementation.

   1.1.2 Fail-over - Grade T

   SNMP is of vital importance to the operation of most networks.
   Existing infrastructures can handle required failover or other
   redundant operations.

   1.1.3 Mutual Authentication - Grade T

   The use of shared secrets described in the document is a well
   understood method of integrity control.  Although shared secrets
   don't necessarily provide full authentication since other parties may
   also have the same secrets, the level of authentication is sufficient
   for the task at hand.  In many cases the SNMP infrastructure will



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   already exist and shared secrets should already be properly managed
   on an operational network.  A failure of the SNMP shared secret
   approach regardless of the AAA protocol will likely leave equipment
   and systems open to substantial misuse bypassing any more elaborate
   AAA authentication.

   1.1.4 Transmission Level Security - Grade T

   SNMPv3 provides many additional security options which were not
   available or were more controversial in previous SNMP versions.

   1.1.5 Data Object Confidentiality - New Grade P (from T)

   The document discusses SNMPv3 which can provide data confidentially
   for data passing over the wire.  There is substantial implied AAA
   architecture (brokers and proxies) in the requirements that full
   conformance is difficult to determine.  In particular, the evaluator
   has difficulty with the concept of "the target AAA entity for whom
   the data is ultimately destined", but will concede that the desired
   requirement is only partially met (most especially with the transfer
   of a PAP password).

   1.1.6 Data Object Integrity - New Grade T (from P)

   SNMP has full capabilities that allow the authentication of the data.
   Brokers, proxies or other intermediaries in the data chain can verify
   the source of the information and determine that the data has not
   been tampered with.  The document downgrades the grade to P because
   of confusion over the integrity checking role of intermediaries.

   1.1.7 Certificate Transport - Grade T

   The requirements require the capability of transporting certificates
   but do not have any specific use for the certificates.  The
   requirements make assumptions that the protocol selected will be
   dependent upon certificates, but this is not necessarily true.  SNMP
   can transport arbitrary objects and can transport certificates if
   necessary.  The document indicates some issues with size of
   certificates and current maximum practical data sizes, however if the
   compact encoding requirement extends to the internal certificate
   information this should be less of an issue.

   1.1.8 Reliable AAA Transport - New Grade T (from P)

   The requirements is stated rather strongly and makes substantial
   assumptions of AAA protocol architecture and based upon current
   protocols and their failings.  SNMP allows for great flexibility in
   retransmission schemes depending upon the importance of the data.



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   1.1.9 Run over IPv4 - Grade T

   SNMP has operated in this mode for many years.

   1.1.10 Run over IPv6 - New Grade T (from P)

   SNMP must support IPv6 for many other systems so support for this
   should be possible by the time the requirement becomes effective.
   The document indicates that experimental versions satisfying this
   requirement are already in existence.

   1.1.11 Support Proxy and Routing Brokers - New Grade T (from P)

   The requirements make significant assumptions about the final
   architecture.  It is well within the capabilities of SNMP to provide
   intermediaries which channel data flows between multiple parties.
   The document downgrades SNMPs compliance with this requirement due to
   issues which are covered more specifically under "Data Object
   Confidentially" which the evaluator has downgraded to P.

   1.1.12 Auditability - New Grade T (from F)

   Data flows inside SNMP are easily auditable by having secondary data
   flows established which provide copies of all information to
   auxiliary servers.  The document grades this as a failure, but this
   support is only minor additions within a more fully fleshed out set
   of data flows.

   1.1.13 Shared Secret Not Required - Grade T

   Shared secrets are not required by SNMP.  They are desirable in many
   instances where a lower level does not provide the necessary
   capabilities.  The document supplies pointers to various security
   modes available.

   1.1.14 Ability to Carry Service Specific Attributes - Grade T

   SNMP has long had the ability for other parties to create new
   unambiguous attributes.

   1.2 Authentication Requirements

   1.2.1 NAI Support - Grade T

   SNMP easily supports this.  NAIs were defined to be easily carried in
   existing protocols.





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   1.2.2 CHAP Support - Grade T

   SNMP can easily provide objects to pass the necessary information for
   CHAP operation.

   1.2.3 EAP Support - New Grade T (from P)

   SNMP can easily provide objects to pass the necessary information for
   EAP operation.  As with CHAP or PAP MIB objects can be created to
   control this operation thus the upgrade from the document grade.

   1.2.4 PAP/Clear-text Passwords - New Grade P (from T)

   SNMP can easily provide objects to pass the necessary information for
   PAP operation.  The requirement about non-disclosure of clear text
   passwords make assumptions about the protocol implementation.  The
   choice to use clear text passwords is inherently insecure and forced
   protocol architecture don't really cover this.  This requirement
   grade is downgraded to P (partial) because the document does not
   really address the confidentially of the data at application proxies.

   1.2.5 Reauthorization on demand - Grade T

   SNMP can easily provide objects to control this operation.

   1.2.6 Authorization w/o Authentication - New Grade T (from T)

   The document makes an incorrect interpretation of this requirement.
   However, SNMP makes no restriction which prevents to desired
   requirements.  No actual change of grade is necessary, since both the
   actual requirements and the incorrect interpretation are satisfied by
   SNMP.

   1.3 Authorization Requirements

   1.3.1 Static and Dynamic IP Addr Assignment - Grade T

   SNMP can easily provide objects to control this operation.

   1.3.2 RADIUS Gateway Capability - Grade T

   As the document describes, with the addition of any necessary
   compatibility variables SNMP can be gatewayed to RADIUS applications.








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   1.3.3 Reject Capability - Grade T

   Any of the active components in the SNMP based structure could decide
   to reject and authentication request for any reason.  Due to mixing
   different levels of requirements the document doesn't attempt to
   directly address this, instead indicating that a higher level
   application can cause this operation.

   1.3.4 Preclude Layer 2 Tunneling - New Grade T (from ?)

   Nothing in SNMP explicitly interacts with the selection of any
   tunneling mechanisms the client may select.  The document author was
   unclear about the needs here.

   1.3.5 Reauth on Demand - Grade T

   SNMP can easily provide objects to control this operation.

   1.3.6 Support for ACLs - Grade T

   The document indicates that should it be desired SNMP can provide
   objects to control these operations.  In addition, active components
   can apply substantial further configurable access controls.

   1.3.7 State Reconciliation - Grade T

   The requirements describe an over broad set of required capabilities.
   The document indicates concern over incompatibilities in the
   requirements, however SNMP can provide methods to allow active
   components to reacquire lost state information.  These capabilities
   directly interact with scalability concerns and care needs to be
   taken when expecting this requirement to be met at the same time as
   the scalability requirements.

   1.3.8 Unsolicited Disconnect - Grade T

   The document indicates that SNMP can easily provide objects to
   control this operation.

   1.4 Accounting Requirements

   1.4.1 Real Time Accounting - Grade T

   SNMP can provide this mode of operation.  The document outlines
   methods both fully within SNMP and using SNMP to interface with other
   transfer methods.  Many providers already use SNMP for real time





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   notification of other network events.  This capability can directly
   interact with scalability concerns and implementation care needs to
   be taken to make this properly interact is large scale environments.

   1.4.2 Mandatory Compact Encoding - Grade T

   The document indicates the possibility of controlling external
   protocols to handle data transmissions where the BER encoding of SNMP
   objects would be considered excessive.  SNMP BER encoded protocol
   elements are generally in a fairly compact encoding form compared
   with text based forms (as used in some existing radius log file
   implementations).  This interacts with the general requirement for
   carrying service specific attributes and the accounting requirement
   for extensibility.  With careful MIB design and future work on SNMP
   payload compression the SNMP coding overhead can be comparable with
   other less extensible protocols.

   1.4.3 Accounting Record Extensibility - Grade T

   SNMP has a strong tradition of allowing vendor specific data objects
   to be transferred.

   1.4.4 Batch Accounting - Grade T

   There are many methods which a SNMP based system could use for batch
   accounting.  The document discusses SNMP parameters to control the
   batching process and indicates that certain existing MIBs contain
   examples of implementation strategies.  SNMP log tables can provide
   accounting information which can be obtained in many methods not
   directly related to real time capabilities.  The underlying system
   buffering requirements are similar regardless of the protocol used to
   transport the information.

   1.4.5 Guaranteed Delivery - Grade T

   SNMP is very amenable to providing guaranteed delivery.  Particularly
   in a pull model (versus the often assumed push model) the data
   gatherer can absolutely know that all data has been transfered.  In
   the common push model the data receiver does not know if the
   originator of the data is having problems delivering the data.

   1.4.6 Accounting Timestamps - Grade T

   Timestamps are used for many SNMP based operations.  The document
   points at the DateAndTime textual convention which is available for
   use.  As with all environments the timestamps accuracy needs
   evaluation before the information should be relied upon.




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   1.4.7 Dynamic Accounting - Grade T

   As long as there is some way to relate multiple records together
   there are no problems resolving multiple records for the same
   session.  This interacts with the scalability requirement and care
   must be taken when implementing a system with both of these
   requirements.

   1.5 MOBILE IP Requirements

   1.5.1 Encoding of MOBILE IP Registration Messages - Grade T

   SNMP can easily provide objects to transfer this information.

   1.5.2 Firewall Friendly - New Grade T (from P)

   SNMP is already deployed in many operational networks.  SNMPv3
   addresses most concerns people had with the operation of previous
   versions.  True SNMPv3 proxies (as opposed to AAA proxies) should
   become commonplace components in firewalls for those organizations
   which require firewalls.

   1.5.3 Allocation of Local Home Agent - New Grade T (from ?)

   SNMP is not concerned with the LHA.  This can be under control of the
   Local network to meet its needs.

   2. Summary Discussion

   SNMP appears to meet most stated requirements.  The areas where the
   SNMP proposal falls short are areas where specific AAA architectures
   are envisioned and requirements based upon that architecture are
   specified.

   Scaling of the protocol family is vital to success of a AAA suite.
   The SNMP protocol has proved scalable in existing network management
   and other high volume data transfer operations.  Care needs to be
   taken in the design of a large scale system to ensure meeting the
   desired level of service, but this is true of any large scale
   project.

   3. General Requirements

   SNMP is well understood and already supported in many ISP and other
   operational environments.  Trust models already exist in many cases
   and can be adapted to provide the necessary access controls needed by
   the AAA protocols.  Important issues with previous versions of SNMP
   have been corrected in the current SNMPv3 specification.



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   The SNMP proposal is silent on the specific data variables and
   message types to be implemented.  This is largely due to the
   requirements not specifying the necessary data elements and the time
   constraints in extracting that information from the base document
   set.  Such a data model is necessary regardless of the ultimate
   protocol selected.

   4. Summary Recommendation

   SNMP appears to fully meet all necessary requirements for the full
   AAA protocol family.

C.2 SNMP CON Evaluation

   Evaluation of SNMP AAA Requirements
   CON Evaluation
   Evaluator - Michael StJohns

   Ref [1] is "Comparison of SNMPv3 Against AAA Network Access
   Requirements", aka 'the document'
   Ref [2] is the aaa eval criteria as modified by us.

   The document uses T to indicate total compliance, P to indicate
   partial compliance and F to indicate no compliance.  For each section
   I've indicated my grade for the section.  If there is no change, I've
   indicated that and the grade given by the authors.

   Section 1 - Per item discussion

   1.1 General Requirements

   1.1.1 Scalability - Although the document indicates compliance with
   the requirement, its unclear how SNMP actually meets those
   requirements.  The document neither discusses how SNMP will scale,
   nor provides applicable references.  The argument that there is an
   existence proof given the deployed SNMP systems appears to assume
   that one manager contacting many agents maps to many agents (running
   AAA) contacting one AAA server.  A server driven system has
   substantially different scaling properties than a client driven
   system and SNMP is most definitely a server (manager) driven system.
   Eval - F

   1.1.2 Fail-over - The document indicates the use of application level
   time outs to provide this mechanism, rather than the mechanism being
   a characteristic of the proposed protocol.  The protocol provides
   only partial compliance with the requirement.  Eval - P





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   1.1.3 Mutual Authentication - There is some slight handwaving here,
   but the protocol's USM mode should be able to support this
   requirement.  Eval - No Change (T)

   1.1.4 Transmission Level Security - The authors should elaborate on
   the specific use of the SNMPv3 modes to support these requirements,
   but the text is minimally acceptable.  Eval - No Change (T)

   1.1.5 Data Object Confidentiality - The authors describe a mechanism
   which does not appear to completely meet the requirement.  VACM is a
   mechanism for an end system (agent) to control access to its data
   based on manager characteristics.  This mechanism does not appear to
   map well to this requirement.  Eval - P

   1.1.6 Data Object Integrity - There appears to be some handwaving
   going on here.  Again, SNMP does not appear to be a good match to
   this requirement due to at least in part a lack of a proxy
   intermediary concept within SNMP.  Eval - F

   1.1.7 Certificate Transport - The document does indicate compliance,
   but notes that optimization might argue for use of specialized
   protocols.  Eval - No Change (T)

   1.1.8 Reliable AAA Transport - The document indicates some confusion
   with the exact extent of this requirement.  Given the modifications
   suggested by the eval group to the explanatory text in [2] for the
   related annotation, the point by point explanatory text is not
   required.  The document does indicate that the use of SNMP is
   irrespective of the underlying transport and the support of this
   requirement is related at least partially to the choice of transport.
   However, SNMP over UDP - the most common mode for SNMP - does not
   meet this requirement.  Eval - No Change (P)

   1.1.9 Run over IPv4 - While the evaluator agrees that SNMPv3 runs
   over V4, the authors need to point to some sort of reference.  Eval -
   No Change (T)

   1.1.10 Run over IPv6 - The document indicates both experimental
   implementations and future standardization of SNMPv3 over IPv6.  Eval
   - No Change (P)

   1.1.11 Support Proxy and Routing Brokers - The section of the
   document (5.5.3) that, by title, should have the discussion of SNMP
   proxy is marked as TBD.  The section notes that the inability to
   completely comply with the data object confidentiality and integrity
   requirements might affect the compliance of this section and the
   evaluator agrees.  Eval - F




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   1.1.12 Auditability - The document indicates no compliance with this
   requirement.  Eval - No Change (F)

   1.1.13 Shared Secret Not Required - Slight handwaving here, but
   SNMPv3 does not necessarily require use of its security services if
   other security services are available.  However, the interaction with
   VACM in the absence of USM is not fully described and may not have
   good characteristics related to this requirement.  Eval - P

   1.1.14 Ability to Carry Service Specific Attributes - SNMP complies
   via the use of MIBs.  Eval - No Change (T)

   1.2 Authentication Requirements

   1.2.1 NAI Support - The document indicates that MIB objects can be
   created to meet this requirement, but gives no further information.
   Eval - P

   1.2.2 CHAP Support - The document indicates that MIB objects can be
   created to meet this requirement, but gives no further information.
   Given the normal CHAP model, its unclear exactly how this would work.
   Eval - F

   1.2.3 EAP Support - The document notes that EAP payloads can be
   carried as specific MIB objects, but also notes that further design
   work would be needed to fully incorporate EAP.  Eval - No Change (P)

   1.2.4 PAP/Clear-text Passwords - The document notes the use of MIB
   objects to carry the clear text passwords and the protection of those
   objects under normal SNMPv3 security mechanisms.  Eval - No Change
   (T)

   1.2.5 Reauthorization on demand - While there's some handwaving here,
   its clear that the specific applications can generate the signals to
   trigger reauthorization under SNMP.  Eval - No Change (T)

   1.2.6 Authorization w/o Authentication - The author appears to be
   confusing the AAA protocol authorization with the AAA user
   authorization and seems to be over generalizing the ability of SNMP
   to deal with general AAA user authorization.  Eval - F

   1.3 Authorization Requirements

   1.3.1 Static and Dynamic IP Addr Assignment - The reference to MIB
   objects without more definite references or descriptions continues to
   be a negative.  While the evaluator agrees that MIB objects can
   represent addresses, the document needs to at least lead the reader
   in the proper direction.  Eval - F



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   1.3.2 RADIUS Gateway Capability - The transport and manipulation of
   Radius objects appears to be only a part of what is required.  Eval -
   P

   1.3.3 Reject Capability - Again, a clarification of how SNMP might
   accomplish this requirement would be helpful.  The overall document
   lacks a theory of operation for SNMP in an AAA role that might have
   clarified the various approaches.  Eval - F

   1.3.4 Preclude Layer 2 Tunneling - Document indicates lack of
   understanding of this requirement.  Eval - F

   1.3.5 Reauth on Demand - See response in 1.3.3 above.  None of the
   text responding to this requirement, nor any other text in the
   document, nor any of the references describes the appropriate
   framework and theory.  Eval - F

   1.3.6 Support for ACLs - The response text again references MIB
   objects that can be defined to do this job.  There is additional
   engineering and design needed before this is a done deal.  Eval - P

   1.3.7 State Reconciliation - The text fails to address the basic
   question of how to get the various parts of the AAA system back in
   sync.  Eval - F

   1.3.8 Unsolicited Disconnect - Assuming that the NAS is an SNMP agent
   for an AAA server acting as an SNMP manager the evaluator concurs.
   Eval - No Change (T).

   1.4 Accounting Requirements

   1.4.1 Real Time Accounting - SNMP Informs could accomplish the
   requirements.  Eval - No Change (T)

   1.4.2 Mandatory Compact Encoding - This is a good and reasonable
   response.  SNMP can vary the style and type of reported objects to
   meet specific needs.  Eval - No Change (T).

   1.4.3 Accounting Record Extensibility - MIBs are extensible.  Eval -
   No Change (T)

   1.4.4 Batch Accounting - MIBs provide data collection at various
   times.  Eval - No Change (T)

   1.4.5 Guaranteed Delivery - There's some weasel wording here with
   respect to what guaranteed means, but the description of mechanisms
   does appear to meet the requirements.  Eval - No Change (T)




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   1.4.6 Accounting Timestamps - Accounting records can use the
   DateAndTime Textual Convention to mark their times.  Eval - No Change
   (T)

   1.4.7 Dynamic Accounting - The author may have partially missed the
   point on this requirement.  While the number of records per session
   is not of great interest, the delivery may be.  The author should go
   a little more into depth on this requirement.  Eval - No Change (T)

   1.5 MOBILE IP Requirements

   1.5.1 Encoding of MOBILE IP Registration Messages - Registration
   messages can probably be encoded as SNMP messages.  Eval - No Change
   (T)

   1.5.2 Firewall Friendly - There's a chicken and egg problem with the
   response to the requirement in that the author hopes that SNMP as an
   AAA protocol will encourage Firewall vendors to make SNMP a firewall
   friendly protocol.  Eval - F

   1.5.3 Allocation of Local Home Agent - The author disclaims an
   understanding of this requirement.  Eval - F

   2. Summary Discussion

   The documents evaluation score was substantially affected by a lack
   of any document, reference or text which described a theory of
   operation for SNMP in AAA mode.  Of substantial concern are the items
   relating to the AAA server to server modes and AAA client to server
   modes and the lack of a map to the SNMP protocol for those modes.

   The evaluator also notes that the scaling issues of SNMP in SNMP
   agent/manager mode are in no way indicative of SNMP in AAA
   client/server mode.  This has a possibility to substantially impair
   SNMPs use in an AAA role.

   However, SNMP may have a reasonable role in the Accounting space.
   SNMP appears to map well with existing technology, and with the
   requirements.

   3. General Requirements

   SNMP appears to meet the general requirements of an IP capable
   protocol, but may not have a proper field of use for all specific
   requirements.






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   4. Summary Recommendation

   Recommended in Part.  SNMP is NOT RECOMMENDED for use as either an
   authentication or authorization protocol, but IS RECOMMENDED for use
   as an accounting protocol.

C.3 RADIUS+ PRO Evaluation

   Evaluation of RADIUS AAA Requirements PRO Evaluation

   Evaluator - Mark Stevens

   Ref [1] is "Comparison of RADIUS Against AAA Network Access
   Requirements"
   Ref [2] is "Framework for the extension of the RADIUS(v2) protocol"
   Ref [3] is the aaa eval criteria as modified by us.

   The documents uses T to indicate total compliance, P to indicate
   partial compliance and F to indicate no compliance.

   For each section I've indicated my grade for the section.  I have
   indicated whether or not my evaluation differs from the statements
   made with respect to RADIUS++.  The evaluation ratings as given below
   may differ from the evaluations codified in the document referred to
   as, "Comparison of RADIUS Against AAA Network Access Requirements"
   without any indication.

   1.1 General Requirements

   1.1.1 [a] Scalability - In as much as a protocol's scalability can be
   measured, the protocol seems to transmit information in a fairly
   efficient manner.So, in that the protocol appears not to consume an
   inordinate amount of bandwidth relative to the data it is
   transmitting, this protocol could be considered scalable.  However,
   the protocol has a limit in the number of concurrent sessions it can
   support between endpoints.  Work arounds exist and are in use.  Eval
   - P (no change)

   1.1.2 [b] Fail-over - The document indicates the use of application
   level time outs to provide this mechanism, rather than the mechanism
   being a characteristic of the proposed protocol.  The fail-over
   requirement indicates that the protocol must provide the mechanism
   rather than the application.  The implication is that the application
   need not be aware that the fail-over and subsequent correction when
   it happens.  The application using the RADIUS++ protocol will be
   involved in fail-over recovery activities.  The protocol layer of the
   software does not appear to have the capability built-in.  Given the
   wording of the requirement: Eval - P (changed from T)



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   1.1.3 [c] Mutual Authentication - The RADIUS++ protocol provides
   shared-secret as a built-in facility for mutual authentication.  The
   authors of the document suggest the use of IPSec to obtain mutual
   authentication functions.  The RADIUS++ protocol provides no road
   blocks to obtaining mutual authentication between instances of AAA
   applications, however the protocol provides no facilities for doing
   so.

   1.1.4 [d] Transmission Level Security - The RADIUS++ protocol
   provides no transmission level security features, nor does it
   preclude the use of IPSec to obtain transmission level security.
   Eval - P (no change)

   1.1.5 [e] Data Object Confidentiality - The document describes a
   RAIDUS++ message designed to server as an envelope in which encrypted
   RADIUS messages (attributes) may be enclosed.  Eval - T (no change)

   1.1.6 [f] Data Object Integrity - Using visible signatures, the
   RADIUS++ protocol appears to meet this requirement.  Eval - T (no
   change)

   1.1.7 [g] Certificate Transport - The document indicates compliance
   through the use of the CMS-Data Radius Attribute (message).  Eval - T
   (no change)

   1.1.8 [h] Reliable AAA Transport - The document points out that
   RADIUS++ can be considered a reliable transport when augmented with
   Layer 2 Tunneling Protocol.  The protocol itself does not provide
   reliability features.  Reliability remains the responsibility of the
   application or a augmenting protocol.  Eval - P (no change)

   1.1.9 [i] Run over IPv4 - Eval - T (no change)

   1.1.10 [j] Run over IPv6 - an IPv6 Address data type must be defined.
   Eval - T (no change)

   1.1.11 [k] Support Proxy and Routing Brokers - There is no mechanism
   for rerouting requests, but an extension can be made to do so.  Eval
   - T (no change)

   1.1.12 [l] Auditability - The document indicates no compliance with
   this requirement.  Eval - F (no change)

   1.1.13 [m] Shared Secret Not Required - RADIUS++ can be configured to
   run with empty shared secret values.  Eval - T (no change)






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   1.1.14 [n] Ability to Carry Service Specific Attributes - Vendor
   escape mechanism can be used for this purpose..  Eval - T  (no
   change)

   1.2 Authentication Requirements

   1.2.1 [a] NAI Support -  Eval - T (no change)

   1.2.2 [b] CHAP Support - Subject to dictionary attacks.  Eval - P
   (changed from T)

   1.2.3 [c] EAP Support - Eval - T (no change)

   1.2.4 [d] PAP/Clear-text Passwords - No end-to-end security, but
   potential for encapsulation exists within current paradigm of the
   protocol.  -  Eval -T (no change)

   1.2.5 [e] Reauthentication on demand -   The RADIUS protocol
   supports re-authentication.  In  case  re-authentication is initiated
   by the user or AAA client, the AAA client can send a new
   authentication request.  Re-authentication can be initiated from the
   visited or home AAA server by sending a challenge message to the AAA
   client.  Eval - T (no change)

   1.2.6 [f] Authorization w/o Authentication - A new message type can
   be created to enable RADIUS++ to support Aw/oA .  Eval - T (no
   change)

   1.3 Authorization Requirements

   1.3.1[a] Static and Dynamic IP Addr Assignment - Both supported.
   IPv6 would require the definition of a new address data type.  Eval -
   P (no change)

   1.3.2 [b] RADIUS Gateway Capability - The transport and manipulation
   of RADIUS objects appears to be only a part of what is required.
   Requirement seems to be worded to preclude RADIUS.  Eval - P (changed
   from T)

   1.3.3 [c] Reject Capability -  Eval -T

   1.3.4 [d] Preclude Layer 2 Tunneling -  I do not see a definition in
   the AAA eval criteria document.  Eval - ?








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   1.3.5 [e] Reauthorization on Demand - Implementation in the field
   demonstrate that extensions to RADIUS can support the desired
   behavior.  Re-authentication is currently coupled to re-
   authorization.  Eval - P (no change)

   1.3.6 [f] Support for ACLs - Currently done in the applications
   behind the RADIUS end points, not the within the protocol.  RADIUS++
   could define additional message types to deal with expanded access
   control within new service areas.  Eval - P (no change)

   1.3.7 [g] State Reconciliation -  Eval - F (no change)

   1.3.8 [h] Unsolicited Disconnect - RADIUS++ extensions to support.
   Eval - T. (no change)

   1.4 Accounting Requirements

   1.4.1 [a] Real Time Accounting -  Eval - T (no change)

   1.4.2 [b] Mandatory Compact Encoding -  Eval - T (no change)

   1.4.3 [c] Accounting Record Extensibility -  Eval - T (no change)

   1.4.4 [d] Batch Accounting - RADIUS++ offers no new features to
   support batch accounting.  Eval - F No change)

   1.4.5 [e] Guaranteed Delivery - Retransmission algorithm employed.
   Eval - T (no change)

   1.4.6 [f] Accounting Timestamps - RADIUS++ extensions support
   timestamps.  Eval - T (no change)

   1.4.7 [g] Dynamic Accounting - RADIUS++ extensions to support.  Eval
   - T (no change)

   1.5 MOBILE IP Requirements

   1.5.1 [a] Encoding of MOBILE IP Registration Messages - RADIUS++
   extensions can be made to include registration messages as an opaque
   payload.  Eval - T (no change)

   1.5.2 [b] Firewall Friendly -  RADIUS  is  known  to  be  operational
   in environments where firewalls acting as a proxy are active.  Eval -
   T (no change)

   1.5.3 [c] Allocation of Local Home Agent -Requirement statement needs
   some clarification and refinement.  Eval - F (no change)




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   2. Summary Discussion

   The RADIUS protocol, and its associated extensions, is  presently not
   fully  compliant  with  the AAA Network Access requirements.
   However, it is  possible with a small effort to extend present
   procedures to meet the requirements as listed in, while maintaining a
   high level  of interoperability  with  the  wide  deployment  and
   installed base of RADIUS clients and servers.

   3. General Requirements

   RADIUS++ the protocol and the application meet the majority of the
   requirements and can be extended to meet the requirements where
   necessary.

   4. Summary Recommendation

   RADIUS++ as it could be developed would provide a level of backward
   compatibility that other protocols cannot achieve.  By extending
   RADIUS in the simple ways described in the documents listed above,
   the transition from existing RADIUS-based installations to RADIUS++
   installations would be easier.  Although accounting continues to be
   weaker than other approaches, the protocol remains a strong contender
   for continued use in the areas of Authorization and Authentication.

C.4 RADIUS+ CON Evaluation

   Evaluation of RADIUS++ (sic) AAA Requirements CON Evaluation
   Evaluator - David Nelson

   Ref [1] is "Comparison of RADIUS Against AAA Network Access
   Requirements", a.k.a. 'the document'
   Ref [2] is "Framework for the extension of the RADIUS(v2) protocol",
   a.k.a. 'the protocol'
   Ref [3] is the AAA evaluation criteria as modified by us.
   Ref [4] is RFC 2869.
   Ref [5] is an expired work in progress "RADIUS X.509 Certificate
   Extensions".
   Ref [6] is RFC 2868

   The document uses T to indicate total compliance, P to indicate
   partial compliance and F to indicate no compliance.  Evaluator's
   Note:  The document [1] pre-dates the protocol [2].  It is clear from
   reading [2], that some of the issues identified as short comings in
   [1] are now addressed in [2].  The evaluator has attempted to take
   note of these exceptions, where they occur.





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   Section 1 - Per item discussion

   1.1 General Requirements

   1.1.1 Scalability - The document [1] indicates partial compliance,
   largely in deference to the "tens of thousands of simultaneous
   requests" language in [3], that has been deprecated.  The issue of
   simultaneous requests from a single AAA client is addressed in [1],
   indicating that the apparent limitation of 256 uniquely identifiable
   outstanding request can be worked around using well known techniques,
   such as the source UDP port number of the request.  The document
   claims "P", and the evaluator concurs.

   1.1.2 Fail-over - The document [1] indicates the use of application
   level time outs to provide the fail-over mechanism.  Since the AAA
   protocol is indeed an application-layer protocol, this seems
   appropriate.  There are significant issues of how to handle fail-
   over in a proxy-chain environment that have not been well addressed,
   however.  The document claims "T", and the evaluator awards "P".

   1.1.3 Mutual Authentication - The document [1] indicates that mutual
   authentication exists in the presence of a User-Password or CHAP-
   Password attribute in an Access-Request packet or the Message-
   Authenticator [4] in any packet.  Once again, this addresses hop-by-
   hop authentication of RADIUS "peers", but does not fully address
   proxy-chain environments, in which trust models would need to be
   established.  The document further indicates that strong mutual
   authentication could be achieved using the facilities of IPsec.  This
   claim would apply equally to all potential AAA protocols, and cannot
   be fairly said to be a property of the protocol itself.  The document
   claims "T", and the evaluator awards "F".

   1.1.4 Transmission Level Security - The document [1] indicates that
   transmission layer security, as defined in [3], is provided in the
   protocol, using the mechanisms described in section 1.1.3.  It should
   be noted that this requirement is now a SHOULD in [3].  The document
   claims "P", and the evaluator concurs.

   1.1.5 Data Object Confidentiality - The document [1] indicates that
   end-to-end confidentiality is not available in RADIUS, but goes on to
   say that it could be added.  The protocol [2] actually makes an
   attempt to specify how this is to be done, in section 4.3.2.2 of [2],
   using a CMS-data attribute, based in large part upon RFC 2630.  The
   evaluator has not, at this time, investigated the applicability of
   RFC 2630 to the AAA work.  The document claims "F", but in light of
   the specifics of the protocol [2], the evaluator awards "P".





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   1.1.6 Data Object Integrity - The document [1] indicates that end-
   to-end integrity is not available in RADIUS, but goes on to say that
   it could be added.  The protocol [2] actually makes an attempt to
   specify how this is to be done, in section 4.3.2.1 of [2], using a
   CMS-data attribute, based in large part upon RFC 2630.  The evaluator
   has not, at this time, investigated the applicability of RFC 2630 to
   the AAA work.  The document claims "F", but in light of the specifics
   of the protocol [2], the evaluator awards "P".

   1.1.7 Certificate Transport - The document [1] indicates that
   certificate transport is not available in RADIUS, but goes on to say
   that it could be added.  The protocol [2] actually makes an attempt
   to specify how this is to be done, in section 4.3.2.3 of [2], using a
   CMS-data attribute, based in large part upon RFC 2630.  The evaluator
   has not, at this time, investigated the applicability of RFC 2630 to
   the AAA work.  Other relevant work in the area of certificate support
   in RADIUS may be found in an expired work in progress, "RADIUS X.509
   Certificate Extensions" [5].  The document claims "F", but in light
   of the specifics of the protocol [2], the evaluator awards "P".

   1.1.8 Reliable AAA Transport - The document [1] indicates that RADIUS
   provides partial compliance with the requirements of the original AAA
   requirements document.  However, in [3], the requirement has been
   simplified to "resilience against packet loss".  Once again, the
   evaluator finds that the protocol [2] meets this criteria on a hop-
   by-hop basis, but fails to effectively address these issues in a
   proxy-chain environment.  The document claims "P", and the evaluator
   awards "F".

   1.1.9 Run over IPv4 - RADIUS is widely deployed over IPv4.  The
   document claims "T", and the evaluator concurs.

   1.1.10 Run over IPv6 - The document [1] indicates that adoption of a
   limited number of new RADIUS attributes to support IPv6 is
   straightforward.  Such discussion has transpired on the RADIUS WG
   mailing list, although that WG is in the process of shutting down.
   The document claims "P", and the evaluator concurs.

   1.1.11 Support Proxy and Routing Brokers - The document [1] indicates
   that RADIUS is widely deployed in proxy-chains of RADIUS servers.
   This is equivalent to the Proxy Broker case, but the Routing Broker
   case is a different requirement.  The protocol [2] does not describe
   any detail of how a Routing Broker might be accommodated, although it
   opens the door by indicating that the RADIUS++ protocol is peer-to-
   peer, rather than client/server.  The document claims "P", and the
   evaluator awards "F".





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   1.1.12 Auditability - The document [1] indicates no compliance with
   this requirement.  The document claims "F", and the evaluator
   concurs.

   1.1.13 Shared Secret Not Required - The document [1] indicates that
   RADIUS may effectively skirt the requirement of application-layer
   security by using a value of "zero" for the pre-shared secret.  While
   this is a bit creative, it does seem to meet the requirement.  The
   document claims "T" and the evaluator concurs.

   1.1.14 Ability to Carry Service Specific Attributes - RADIUS has a
   well defined Vendor-Specific Attribute, which, when properly used,
   does indeed provide for the ability to transport service-specific
   attributes.  The document claims "T", and the evaluator concurs.

   1.2 Authentication Requirements

   1.2.1 NAI Support - The document [1] indicates that RADIUS specifies
   the NAI as one of the suggested formats for the User-Name attribute.
   The document claims "T", and the evaluator agrees.

   1.2.2 CHAP Support - CHAP support is widely deployed in RADIUS.  The
   document claims [1] "T", and the evaluator concurs.

   1.2.3 EAP Support - The document [1] indicates that EAP support in
   RADIUS is specified in [4].  The document claims [1] "T", and the
   evaluator concurs.

   1.2.4 PAP/Clear-text Passwords - The document [1] indicates that
   RADIUS provides protection of clear-text passwords on a hop-by-hop
   basis.  The protocol [2] indicates how additional data
   confidentiality may be obtained in section 4.3.2.2 of [2], using a
   CMS-data attribute, based in large part upon RFC 2630.  The evaluator
   has not, at this time, investigated the applicability of RFC 2630 to
   the AAA work.  The document claims [1] "F", but in light of the
   specifics of the protocol [2], the evaluator awards "P".

   1.2.5 Reauthentication on demand - The document [1] indicates that
   RADIUS may accomplish re-authentication on demand by means of an
   Access-Challenge message sent from a server to a client.  The
   evaluator disagrees that this is likely to work for a given session
   once an Access-Accept message has been received by the client.  The
   document claims "T", and the evaluator awards "F".

   1.2.6 Authorization w/o Authentication - This requirement, as applied
   to the protocol specification, mandates that non- necessary
   authentication credentials not be required in a request for
   authorization.  The actual decision to provide authorization in the



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   absence of any authentication resides in the application (e.g. AAA
   server).  RADIUS does require some form of credential in request
   messages.  The document [1] claims "F", and the evaluator concurs.

   1.3 Authorization Requirements

   1.3.1 Static and Dynamic IP Addr Assignment - The document [1]
   indicates that RADIUS can assign IPv4 addresses, and can easily be
   extended to assign IPv6 addresses (see section 1.1.10).  Of greater
   concern, however, is the issue of static vs. dynamic addresses.  If
   dynamic address has the same meaning as it does for DHCP, then there
   are issues of resource management that RADIUS has traditionally not
   addressed.  The document claims "P", and the evaluator concurs.

   1.3.2 RADIUS Gateway Capability - The document [1] maintains that a
   RADIUS++ to RADIUS gateway is pretty much a tautology.  The document
   claims "T", and the evaluator concurs.

   1.3.3 Reject Capability - The document [1] maintains that RADIUS
   Proxy Servers, and potentially RADIUS++ Routing Brokers, have the
   ability to reject requests based on local policy.  The document
   claims "T" and the evaluator concurs.

   1.3.4 Preclude Layer 2 Tunneling - The document [1] indicates that
   [6] defines support for layer two tunneling in RADIUS.  The document
   claims "T", and the evaluator concurs.

   1.3.5 Reauth on Demand - The document [1] indicates that RADIUS
   provides this feature by means of the Session-Timeout and
   Termination- Action attributes.  While this may, in fact, be
   sufficient to provide periodic re-authorization, it would not provide
   re- authorization on demand.  The protocol [2] does not address this
   further.  The document claims "P", and the evaluator awards "F".

   1.3.6 Support for ACLs - The document [1] describes the attributes in
   RADIUS that are used to convey the access controls described in [3].
   Certain of these (e.g. QoS) are not currently defined in RADIUS, but
   could easily be defined as new RADIUS attributes.  The document
   claims "P", and the evaluator concurs.

   1.3.7 State Reconciliation - The document [1] addresses each of the
   sub- items, as listed in the original AAA requirements document.  In
   reviewing the document against the modified requirements of [3],
   there is still an issue with server-initiated state reconciliation
   messages.  While the protocol [2] makes provision for such messages,
   as servers are allowed to initiate protocol dialogs, no detailed





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   message formats are provided.  This is an area that has traditionally
   been a short coming of RADIUS.  The document claims "P", and the
   evaluator awards "F".

   1.3.8 Unsolicited Disconnect - Much of the discussion from the
   previous section applies to this section.  The document [1] claims
   "F", and the evaluator concurs.

   1.4 Accounting Requirements

   1.4.1 Real Time Accounting - RADIUS Accounting is widely deployed and
   functions within the definition of real time contained in [3].  The
   document [1] claims "T", and the evaluator concurs.

   1.4.2 Mandatory Compact Encoding - RADIUS Accounting contains TLVs
   for relevant accounting information, each of which is fairly compact.
   Note that the term "bloated" in [3] is somewhat subjective.  The
   document [1] claims "T", and the evaluator concurs.

   1.4.3 Accounting Record Extensibility - RADIUS Accounting may be
   extended by means of new attributes or by using the Vendor-Specific
   attribute.  While it has been argued that the existing attribute
   number space is too small for the required expansion capabilities,
   the protocol [2] addresses this problem in section 3.0, and its
   subsections, of [2].  The document [1] claims "T", and the evaluator
   concurs.

   1.4.4 Batch Accounting - RADIUS has no explicit provisions for batch
   accounting, nor does the protocol [2] address how this feature might
   be accomplished.  The document [1] claims "F", and the evaluator
   concurs.

   1.4.5 Guaranteed Delivery - RADIUS Accounting is widely deployed and
   provides guaranteed delivery within the context of the required
   application-level acknowledgment.  The document [1] claims "T", and
   the evaluator concurs.

   1.4.6 Accounting Timestamps - The document [1] indicates that this
   feature is specified in [4] as the Event-Timestamp attribute.  The
   document claims [1] "T", and the evaluator concurs.

   1.4.7 Dynamic Accounting - The document [1] indicates that this
   requirement is partially met using the accounting interim update
   message as specified in [4].  In addition, there was work in the
   RADIUS WG regarding session accounting extensions that has not been
   included in [4], i.e., some expired works in progress.  The document
   claims [1] "P", and the evaluator concurs.




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   1.5 MOBILE IP Requirements

   1.5.1 Encoding of MOBILE IP Registration Messages - The document [1]
   claims "F", and the evaluator concurs.

   1.5.2 Firewall Friendly - The document [1] indicates that RADIUS
   deployment is know to have occurred in fire-walled environments.  The
   document claims "T", and the evaluator concurs.

   1.5.3 Allocation of Local Home Agent - The document [1] claims "F",
   and the evaluator concurs.

   2. Summary Discussion

   The document [1] and the protocol [2] suffer from having been written
   in a short time frame.  While the protocol does provide specific
   guidance on certain issues, citing other relevant documents, it is
   not a polished protocol specification, with detailed packet format
   diagrams.  There is a pool of prior work upon which the RADIUS++
   protocol may draw, in that many of the concepts of Diameter were
   first postulated as works in progress within the RADIUS WG, in an
   attempt to "improve" the RADIUS protocol.  All of these works in
   progress have long since expired, however.

   3. General Requirements

   RADIUS++ meets many of the requirements of an AAA protocol, as it is
   the current de facto and de jure standard for AAA.  There are long-
   standing deficiencies in RADIUS, which have been well documented in
   the RADIUS and NASREQ WG proceedings.  It is technically possible to
   revamp RADIUS to solve these problems.  One question that will be
   asked, however, is:  "What significant differences would there be
   between a finished RADIUS++ protocol and the Diameter protocol?".

   4. Summary Recommendation

   Recommended in part.  What may possibly be learned from this
   submission is that it is feasible to have a more RADIUS-compliant
   RADIUS-compatibility mode in Diameter.












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C.5 Diameter PRO Evaluation

   Evaluation of Diameter against the AAA Requirements
   PRO Evaluation
   Evaluator - Basavaraj Patil

   Ref [1] is "Diameter Framework Document".
   Ref [2] is "Diameter NASREQ Extensions".
   Ref [3] is the AAA evaluation criteria as modified by us.
   Ref [4] is "Diameter Accounting Extensions".
   Ref [5] is "Diameter Mobile IP Extensions".
   Ref [6] is "Diameter Base Protocol".
   Ref [7] is "Diameter Strong Security Extension".
   Ref [8] is "Comparison of Diameter Against AAA Network Access
   Requirements".

   The document uses T to indicate total compliance, P to indicate
   partial compliance and F to indicate no compliance.

   Evaluator's note : The Diameter compliance document [8] claims Total
   "T" compliance with all the requirements except :  - 1.2.5 - 1.5.2

   Section 1 - Per item discussion

   1.1 General Requirements

   1.1.1 Scalability

   Diameter is an evolution of RADIUS and has taken into consideration
   all the lessons learned over many years that RADIUS has been in
   service.  The use of SCTP as the transport protocol reduces the need
   for multiple proxy servers (Sec 3.1.1 Proxy Support of [1]) as well
   as removing the need for application level acks.  The use and support
   of forwarding and redirect brokers enhances  scalability.  Evaluator
   concurs with the "T" compliance on this requirement.

   1.1.2 Fail-over

   Again with the use of SCTP, Diameter is able to detect disconnect
   indications upon which it switches to an alternate server (Sec 4.0
   [6]).  Also Requests and Responses do not have to follow the same
   path and this increases the reliability.  Evaluator concurs with the
   "T" compliance on this requirement.








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   1.1.3 Mutual Authentication

   The compliance document quotes the use of symmetric transforms for
   mutual authentication between the client and server (Sec 7.1 of
   [6]).  The use of IPSec as an underlying security mechanism and
   thereby use the characteristics of IPSec itself to satisfy this
   requirement is also quoted.  Evaluator concurs with the "T"
   compliance on this requirement.

   1.1.4 Transmission Level Security

   Although this requirement has been deprecated by the AAA evaluation
   team the document complies with it based on the definition (referring
   to hop-by-hop security).  Section 7.1 of [6] provides the details of
   how this is accomplished in Diameter.  Evaluator concurs with the "T"
   compliance on this requirement.

   1.1.5 Data Object Confidentiality

   This requirement seems to have come from Diameter.  Ref [7] explains
   in detail the use of Cryptographic Message Syntax (CMS) to achieve
   data object confidentiality.  A CMS-Data AVP is defined in [7].
   Evaluator concurs with the "T" compliance on this requirement.

   1.1.6 Data Object Integrity

   Using the same argument as above and the hop-by-hop security feature
   in the protocol this requirement is completely met by Diameter.
   Evaluator concurs with the "T" compliance on this requirement.

   1.1.7 Certificate Transport

   Again with the use of the CMS-Data AVP, objects defined as these
   types of attributes allow the transport of certificates.  Evaluator
   concurs with the "T" compliance on this requirement.

   1.1.8 Reliable AAA Transport

   Diameter recommends that the protocol be run over SCTP.  SCTP
   provides the features described for a reliable AAA transport.
   Although the compliance is not a perfect fit for the definition of
   this tag item, it is close enough and the functionality achieved by
   using SCTP is  the same.  Evaluator concurs with the "T" compliance
   on this requirement.







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   1.1.9 Run over IPv4

   Is an application layer protocol and does not depend on the
   underlying version of IP.  Evaluator concurs with the "T" compliance
   on this requirement.

   1.1.10 Run over IPv6

   Is an application layer protocol and does not depend on the
   underlying version of IP.  Evaluator concurs with the "T" compliance
   on this requirement.

   1.1.11 Support Proxy and Routing Brokers

   Section 3.1.1/2 of the framework document [1] provides an explanation
   of how Diameter supports proxy and routing brokers.  In fact it
   almost appears as though the requirement for a routing broker came
   from Diameter.  Evaluator concurs with the "T" compliance on this
   requirement.

   1.1.12 Auditability

   With the use of CMS-Data AVP [7] a trail is created when proxies are
   involved in the transaction.  This trail can provide auditability.
   Evaluator concurs with the "T" compliance on this requirement.

   1.1.13 Shared Secret Not Required

   With the use of IPSec as the underlying security mechanism, Diameter
   does not require the use of shared secrets for message
   authentication.  Evaluator concurs with the "T" compliance on this
   requirement.

   1.1.14 Ability to Carry Service Specific Attributes

   The base protocol [6] is defined by Diameter and any one else can
   define specific extensions on top of it.  Other WGs in the IETF can
   design an extension on the base protocol with specific attributes and
   have them registered by IANA.  Evaluator concurs with the "T"
   compliance on this requirement.











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   1.2 Authentication Requirements

   1.2.1 NAI Support

   The base protocol [6] defines an AVP that can be used to support
   NAIs.  Diameter goes one step further by doing Message forwarding
   based on destination NAI AVPs.  Evaluator concurs with the "T"
   compliance on this requirement.

   1.2.2 CHAP Support

   Reference [2] section 3.0 describes the support for CHAP.  Evaluator
   concurs with the "T" compliance on this requirement.

   1.2.3 EAP Support

   Reference [2] section 4.0 describes the support for EAP.  Evaluator
   concurs with the "T" compliance on this requirement.

   1.2.4 PAP/Clear-text Passwords

   Reference [2] section 3.1.1.1 describes the support for PAP.
   Evaluator concurs with the "T" compliance on this requirement.

   1.2.5 Reauthentication on demand

   The use of Session-Timeout AVP as the mechanism for reauthentication
   is claimed by the compliance document.  However no direct references
   explaining this in the base protocol [6] document were found.

   Evaluator deprecates the compliance on this to a "P"

   Note: However this is a trivial issue.

   1.2.6 Authorization w/o Authentication

   Diameter allows requests to be sent without having any authentication
   information included.  A Request-type AVP is defined in [2] and it
   can specify authorization only without containing any authentication.
   Evaluator concurs with the "T" compliance on this requirement.











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   1.3 Authorization Requirements

   1.3.1 Static and Dynamic IP Addr Assignment

   The base protocol includes an AVP for carrying the  address.
   References [6.2.2 of 2] and [4.5 of 5] provide detailed  explanations
   of how this can be done.  Evaluator concurs with the "T" compliance
   on this requirement.

   1.3.2 RADIUS Gateway Capability

   One of the basic facets of Diameter is to support backward
   compatibility and act as a RADIUS gateway in certain environments.
   Evaluator concurs with the "T" compliance on this requirement.

   1.3.3 Reject Capability

   Based on the explanation provided in the compliance document for this
   requirement evaluator concurs with the "T" compliance on this
   requirement.

   1.3.4 Preclude Layer 2 Tunneling

   Ref [2] defines AVPs supporting L2 tunnels  Evaluator concurs with
   the "T" compliance on this requirement.

   1.3.5 Reauth on Demand

   A session timer defined in [6] is used for reauthorization.  However
   Diameter allows reauthorization at any time.  Since this is a peer-
   to-peer type of protocol any entity can initiate a reauthorization
   request.  Evaluator concurs with the "T" compliance on this
   requirement.

   1.3.6 Support for ACLs

   Diameter defines two methods.  One that supports backward
   compatibility for RADIUS and another one with the use of a standard
   AVP with the filters encoded in it.  Evaluator concurs with the "T"
   compliance on this requirement.

   1.3.7 State Reconciliation

   A long explanation on each of the points defined for this tag item in
   the requirements document.  Evaluator concurs with the "T" compliance
   for this requirement.





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   1.3.8 Unsolicited Disconnect

   The base protocol [6] defines a set of session termination messages
   which can be used for unsolicited disconnects.  Evaluator concurs
   with the "T" compliance on this requirement.

   1.4 Accounting Requirements

   1.4.1 Real Time Accounting

   Evaluator concurs with the "T" compliance based on explanations in
   [4].

   1.4.2 Mandatory Compact Encoding

   Use of Accounting Data Interchange Format (ADIF)-Record-AVP for
   compact encoding of accounting data.  Evaluator concurs with the "T"
   compliance.

   1.4.3 Accounting Record Extensibility

   ADIF can be extended.  Evaluator concurs with the "T" compliance.

   1.4.4 Batch Accounting

   Sec 1.2 of [4] provides support for batch accounting.

   1.4.5 Guaranteed Delivery

   Sections 2.1/2 of [4] describe messages that are used to guarantee
   delivery of accounting records.  Evaluator concurs with the "T"
   compliance.

   1.4.6 Accounting Timestamps

   Timestamp AVP [6] is present in all accounting messages.  Evaluator
   concurs with the "T" compliance.

   1.4.7 Dynamic Accounting

   Interim accounting records equivalent to a call-in-progress can be
   sent periodically.  Evaluator concurs with the "T" compliance.









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   1.5 MOBILE IP Requirements

   1.5.1 Encoding of MOBILE IP Registration Messages

   Ref [5] provides details of how Diameter can encode MIP messages.
   Evaluator concurs with the "T" compliance.

   1.5.2 Firewall Friendly

   Some handwaving here and a possible way of solving the firewall
   problem with a Diameter proxy server.  Document claims "T", evaluator
   deprecates it to a "P"

   1.5.3 Allocation of Local Home Agent

   Diameter can assign a local home agent in a visited network in
   conjunction with the FA in that network.  Evaluator concurs with the
   "T"

   Summary Recommendation

   Diameter is strongly recommended as the AAA protocol.  The experience
   gained from RADIUS deployments has been put to good use in the design
   of this protocol.  It has also been designed with extensibility in
   mind thereby allowing different WGs to develop their own specific
   extension to satisfy their requirements.  With the use of SCTP as the
   transport protocol, reliability is built in.  Security has been
   addressed in the design of the protocol and  issues that were
   discovered in RADIUS have been fixed.  Diameter also  is a session
   based protocol which makes it more scalable.  The support for
   forwarding and redirect brokers is well defined and  this greatly
   improves the scalability aspect of the protocol.

   Lastly the protocol has been implemented by at least a few people and
   interop testing done.  This in itself is a significant step and a
   positive point for Diameter to be the AAA protocol.

C.6 Diameter CON Evaluation

   Evaluation of Diameter against the AAA Requirements
   CON Brief
   Evaluator: Barney Wolff









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   Section 1 - Per item discussion

   1.1 General Requirements

   1.1.1 Scalability - P (was T)  The evaluator is concerned with
   scalability to the small, not to the large.  Diameter/SCTP may prove
   difficult to retrofit to existing NAS equipment.

   1.1.2 Fail-over - P (was T)  SCTP gives an indication of peer
   failure, but nothing in any Diameter or SCTP document the evaluator
   was able to find even mentions how or when to switch back to a
   primary server to which communication was lost.  After a failure, the
   state machines end in a CLOSED state and nothing seems to trigger
   exit from that state.  It was not clear whether a server, on
   rebooting, would initiate an SCTP connection to all its configured
   clients.  If not, and in any case when the communication failure was
   in the network rather than in the server, the client must itself,
   after some interval, attempt to re-establish communication.  But no
   such guidance is given.

   Of course, the requirement itself fails to mention the notion of
   returning to a recovered primary.  That is a defect in the
   requirement.  The evaluator has had unfortunate experience with a
   vendor's RADIUS implementation that had exactly the defect that it
   often failed to notice recovery of the primary.

   1.1.3 Mutual Authentication - T

   1.1.4 Transmission Level Security - T

   1.1.5 Data Object Confidentiality - P (was T).  Yes, the CMS data
   type is supported.  But the work in progress, "Diameter Strong
   Security Extension", says:

      Given that asymmetric transform operations are expensive, Diameter
      servers MAY wish to use them only when dealing with inter-domain
      servers, as shown in Figure 3.  This configuration is normally
      desirable since Diameter entities within a given administrative
      domain MAY inherently trust each other.  Further, it is desirable
      to move this functionality to the edges, since NASes do not
      necessarily have the CPU power to perform expensive cryptographic
      operations.

   Given all the fuss that has been made about "end-to-end"
   confidentiality (which really means "NAS-to-home_server"), the
   evaluator finds it absurd that the proposed solution is acknowledged
   to be unsuited to the NAS.




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   1.1.6 Data Object Integrity - P (was T).  See above.

   1.1.7 Certificate Transport - T

   1.1.8 Reliable AAA Transport - T

   1.1.9 Run over IPv4 - T

   1.1.10 Run over IPv6 - T

   1.1.11 Support Proxy and Routing Brokers - T

   1.1.12 Auditability - T (based on our interpretation as non-
   repudiation, rather than the definition given in reqts)

   1.1.13 Shared Secret Not Required - T

   1.1.14 Ability to Carry Service Specific Attributes - T

   1.2 Authentication Requirements

   1.2.1 NAI Support - T

   1.2.2 CHAP Support - T

   1.2.3 EAP Support - T

   1.2.4 PAP/Clear-text Passwords - T

   1.2.5 Reauthentication on demand - P (was T).  No mechanism was
   evident for the server to demand a reauthentication, based for
   example on detection of suspicious behavior by the user.  Session-
   timeout is not sufficient, as it must be specified at the start.

   1.2.6 Authorization w/o Authentication - T

   1.3 Authorization Requirements

   1.3.1 Static and Dynamic IP Addr Assignment - T

   1.3.2 RADIUS Gateway Capability - P (was T).  RADIUS has evolved from
   the version on which Diameter was based.  EAP is a notable case where
   the convention that the Diameter attribute number duplicates the
   RADIUS one is violated.  No protocol, not even RADIUS++, can claim a
   T on this.

   1.3.3 Reject Capability - T (The evaluator fails to understand how
   any AAA protocol could rate anything other than T on this.)



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   1.3.4 Preclude Layer 2 Tunneling - T

   1.3.5 Reauth on Demand - P (was T).  As with reauthentication, there
   is no evident mechanism for the server to initiate this based on
   conditions subsequent to the start of the session.

   1.3.6 Support for ACLs - P (was T).  The evaluator finds the Filter-
   Rule AVP laughably inadequate to describe filters.  For example, how
   would it deal with restricting SMTP to a given server, unless all IP
   options are forbidden so the IP header length is known?  No real NAS
   could have such an impoverished filter capability, or it would not
   survive as a product.

   1.3.7 State Reconciliation - P (was T).  It is difficult for the
   evaluator to understand how this is to work in a multi-administration
   situation, or indeed in any proxy situation.  Furthermore, SRQ with
   no session-id is defined to ask for info on all sessions, not just
   those "owned" by the requester.

   1.3.8 Unsolicited Disconnect - T

   1.4 Accounting Requirements

   1.4.1 Real Time Accounting - T

   1.4.2 Mandatory Compact Encoding - T

   1.4.3 Accounting Record Extensibility - T

   1.4.4 Batch Accounting - P (was T).  The evaluator suspects that
   simply sending multiple accounting records in a single request is not
   how batch accounting should or will be done.

   1.4.5 Guaranteed Delivery - T

   1.4.6 Accounting Timestamps - T  (The evaluator notes with amusement
   that NTP time cycles in 2036, not 2038 as claimed in the Diameter
   drafts.  It's Unix time that will set the sign bit in 2038.)

   1.4.7 Dynamic Accounting - T

   1.5 MOBILE IP Requirements

   1.5.1 Encoding of MOBILE IP Registration Messages - T

   1.5.2 Firewall Friendly - F (was T).  Until such time as firewalls
   are extended to know about or proxy SCTP, it is very unlikely that
   SCTP will be passed.  Even then, the convenient feature of being able



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   to send a request from any port, and get the reply back to that port,
   means that a simple port filter will not be sufficient, and
   statefulness will be required.  Real friendship would require that
   both source and dest ports be 1812.

   1.5.3 Allocation of Local Home Agent - T

   2. Summary Discussion

   In some areas, Diameter is not completely thought through.  In
   general, real effort has gone into satisfying a stupendous range of
   requirements.

   3. General Requirements

   Diameter certainly fails the KISS test.  With SCTP, the drafts add up
   to 382 pages - well over double the size of RADIUS even with
   extensions.  The evaluator sympathizes with the political instinct
   when faced with a new requirement no matter how bizarre, to say "we
   can do that" and add another piece of filigree.  But the major places
   where Diameter claims advantage over RADIUS, namely "end-to-end"
   confidentiality and resource management, are just the places where
   some hard work remains, if the problems are not indeed intractable.

   More specifically, the evaluator sees no indication that specifying
   the separate transport protocol provided any advantage to defray the
   large increase in complexity.  Application acks are still required,
   and no benefit from the transport acks was evident to the evaluator.
   Nor was there any obvious discussion of why "sequenced in-order"
   delivery is required, when AAA requests are typically independent.
   SCTP offers out-of-order delivery, but Diameter seems to have chosen
   not to use that feature.

   Whether TLV encoding or ASN.1/BER is superior is a religious
   question, but Diameter manages to require both, if the "strong"
   extension is implemented.  The evaluator has a pet peeve with length
   fields that include the header, making small length values invalid,
   but that is a minor point.

   Finally, interoperability would be greatly aided by defining a
   standard "dictionary" format by which an implementation could adopt
   wholesale a set of attributes, perhaps from another vendor, and at
   least know how to display them.  That is one of the advantages of
   MIBs.







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   4. Summary Recommendation

   Diameter is clearly close enough to meeting the myriad requirements
   that it is an acceptable candidate, though needing some polishing.
   Whether the vast increase in complexity is worth the increase in
   functionality over RADIUS is debatable.

C.7 COPS PRO Evaluation

   Evaluation of COPS AAA Requirements
   PRO Evaluation
   Evaluator - David Nelson

   Ref [1] is "Comparison of COPS Against the AAA NA Requirements", work
   in progress, a.k.a. 'the document'
   Ref [2] is RFC 2748 a.k.a. 'the protocol'
   Ref [3] is the AAA evaluation criteria as modified by us.
   Ref [4] is "AAA Protocols: Comparison between RADIUS, Diameter, and
   COPS"  work in progress.
   Ref [5] is "COPS Usage for AAA", work in progress.

   This document uses T to indicate total compliance, P to indicate
   partial compliance and F to indicate no compliance.

   Section 1 - Per item discussion

   1.1 General Requirements

   1.1.1 Scalability - The document [1] claims "T", and the evaluator
   concurs.

   1.1.2 Fail-over - The document [1] claims "T", and the evaluator
   concurs.

   1.1.3 Mutual Authentication - The document claims "T", and the
   evaluator concurs.

   1.1.4 Transmission Level Security - The document [1] indicates that
   transmission layer security, as defined in [3], is provided in the
   protocol, using the mechanisms described in [2].  It should be noted
   that this requirement is now a SHOULD in [3].  The document claims
   "T", and the evaluator concurs.

   1.1.5 Data Object Confidentiality - The document [1] indicates that
   end-to-end confidentiality is provided using a CMS-data attribute,
   based in large part upon RFC 2630.  The evaluator has not, at this
   time, investigated the applicability of RFC 2630 to the AAA work.
   The document claims "T", and the evaluator concurs.



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   1.1.6 Data Object Integrity - The document [1] indicates that data
   object integrity is provided using a CMS-data attribute, based in
   large part upon RFC 2630.  The evaluator has not, at this time,
   investigated the applicability of RFC 2630 to the AAA work.  The
   document claims "T", and the evaluator concurs.

   1.1.7 Certificate Transport - The document [1] indicates that
   certificate transport is provided using a CMS-data attribute, based
   in large part upon RFC 2630 and RFC 1510.  The evaluator has not, at
   this time, investigated the applicability of RFC 2630 to the AAA
   work.  The document claims "T", and the evaluator concurs.

   1.1.8 Reliable AAA Transport - The document [1] indicates that COPS
   uses TCP, which certainly meets the requirements for a reliable
   transport.  The document claims "T", and the evaluator concurs.

   1.1.9 Run over IPv4 - The document [1] claims "T", and the evaluator
   concurs.

   1.1.10 Run over IPv6 - The document [1] claims "T", and the evaluator
   concurs.

   1.1.11 Support Proxy and Routing Brokers - Reasonable detail of proxy
   operations is provided in [5].  The document [1] claims "T", and the
   evaluator concurs.

   1.1.12 Auditability - The document [1] alludes to a History PIB that
   would enable auditing without explaining how it would work.  The AAA
   Extension [5] does not provide additional insight.  The document
   claims "T", and the evaluator awards "P".

   1.1.13 Shared Secret Not Required - The document [1] claims "T" and
   the evaluator concurs.

   1.1.14 Ability to Carry Service Specific Attributes -  The document
   [1] claims "T", and the evaluator concurs.

   1.2 Authentication Requirements

   1.2.1 NAI Support - The document [1] indicates that NAI is to be
   supported in the Information Model, but notes that for cases where
   certificates are in use, the more restrictive syntax of RFC 2459
   applies.  The document claims "T", and the evaluator awards "P".

   1.2.2 CHAP Support - The document [1] claims "T", and the evaluator
   concurs.





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   1.2.3 EAP Support - The document [1] claims "T", and the evaluator
   concurs.

   1.2.4 PAP/Clear-text Passwords - The document [1] indicates
   compliance, presumably using a CMS-data attribute, based in large
   part upon RFC 2630.  The evaluator has not, at this time,
   investigated the applicability of RFC 2630 to the AAA work.  The
   document claims "T", and the evaluator concurs.

   1.2.5 Reauthentication on demand - The document [1] claims "T", and
   the evaluator concurs.

   1.2.6 Authorization w/o Authentication - This requirement, as applied
   to the protocol specification, mandates that non- necessary
   authentication credentials not be required in a request for
   authorization.  The actual decision to provide authorization in the
   absence of any authentication resides in the application (e.g. AAA
   server).  The document [1] claims "T", and the evaluator concurs.

   1.3 Authorization Requirements

   1.3.1 Static and Dynamic IP Addr Assignment -  The document [1]
   claims "T", and the evaluator concurs.

   1.3.2 RADIUS Gateway Capability - The document [1] claims "T", and in
   the absence of any detailed discussion of how this is accomplished,
   in either [1] or [5], the evaluator awards "P".

   1.3.3 Reject Capability - The document claims [1] "T" and the
   evaluator concurs.

   1.3.4 Preclude Layer 2 Tunneling - The document [1] claims "T", and
   in the absence of any detailed discussion of how this is
   accomplished, in either [1] or [5], the evaluator awards "P".

   1.3.5 Reauth on Demand -  The document [1] claims "T", and the
   evaluator concurs.

   1.3.6 Support for ACLs - The document [1] "T", and the evaluator
   concurs.

   1.3.7 State Reconciliation - The document [1] "T", and the evaluator
   concurs.

   1.3.8 Unsolicited Disconnect - The document [1] claims "T", and the
   evaluator concurs.





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   1.4 Accounting Requirements

   1.4.1 Real Time Accounting -  The document [1] claims "T", and the
   evaluator concurs.

   1.4.2 Mandatory Compact Encoding - Note that the term "bloated" in
   [3] is somewhat subjective.  The document [1] claims "T", and the
   evaluator concurs.

   1.4.3 Accounting Record Extensibility -  The document [1] claims "T",
   and the evaluator concurs.

   1.4.4 Batch Accounting - The protocol [2] [5] does not address how in
   detail this feature might be accomplished.  The document [1] claims
   "T", and the awards "P".

   1.4.5 Guaranteed Delivery - Guaranteed delivery is provided by TCP.
   The document [1] claims "T", and the evaluator concurs.

   1.4.6 Accounting Timestamps - The document [1] claims "T", and the
   evaluator concurs.

   1.4.7 Dynamic Accounting - The document [1] claims "T", and the
   evaluator concurs.

   1.5 MOBILE IP Requirements

   1.5.1 Encoding of MOBILE IP Registration Messages - The document [1]
   claims "T", and the evaluator concurs.

   1.5.2 Firewall Friendly - The document [1] claims "T", and the
   evaluator concurs.

   1.5.3 Allocation of Local Home Agent - The document [1] claims "T",
   and the evaluator concurs.

   2. Summary Discussion

   It may appear, upon initial inspection, that the evaluator has not
   lent a critical eye to the compliance assertions of the document [1].
   First, this memo is a "PRO" brief, and as such reasonable benefit of
   doubt is to be given in favor of the protocol submission.  Second,
   there is a fundamental conceptual issue at play.  The COPS-PR model
   provides a sufficient set of basic operations and commands, a
   stateful model, the ability for either "peer" to initiate certain
   kinds of requests, as well as an extensible command set, to be able
   to support a wide variety of network and resource management
   protocols.  The details of protocol specific messages is left to



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   Policy Information Base (PIB) data objects.  Since no AAA PIB has
   been written, the evacuator can only (optimistically) assess the
   inherent capabilities of the base protocol to accomplish the intended
   requirements of [3], given a reasonable set of assumptions about what
   an AAA PIB might look like.

   In some sense, this akin to asserting that a given algorithm can be
   correctly implemented in a specific programming language, without
   actually providing the code.

   The PIB model used by COPS is a powerful and flexible model.  The
   protocol document [5] spends a considerable amount of time
   enumerating and describing the benefits of this data model, and
   explaining its roots in Object Oriented (OO) design methodology.
   Analogies are made to class inheritance and class containment, among
   others.  It's always hard to say bad things about OO.

   3. General Requirements

   COPS-AAA would appear to meet (totally or partially) all of the
   requirements of [3], at least as can be determined without the
   benefit of an AAA PIB.

   4. Summary Recommendation

   Recommended with reservation.  Before final acceptance of COPS-AAA,
   someone is going to have to write the AAA PIB and evaluate its
   details.

C.8 COPS CON Evaluation

   Evaluation of COPS against the AAA Requirements
   CON Evaluation
   Evaluator - David Mitton

   The Primary document discussed here is [COPSComp] and the arguments
   therein based on the proposal [COPSAAA].

   [COPSComp] "Comparison of COPS Against the AAA NA Requirements", Work
   in Progress.
   [COPSAAA] "COPS Usage for AAA", Work in Progress.
   [EksteinProtoComp] "AAA Protocols: Comparison between RADIUS,
   Diameter, and COPS", Work in Progress.








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   References: (in order of relevancy)

   [COPSBase]  Durham, D., Boyle, J., Cohen, R., Herzog, S., Rajan, R.
               and A. Sastry, "The Common Open Policy Service Protocol",
               RFC 2748, January 2000.

   [COPSFwork] Yavatkar, R., Pendarakis, D. and R. Guerin, "A Framework
               for Policy-based Admission Control", RFC 2753, January
               2000.

   [COPSPR]    "COPS Usage for Policy Provisioning", Work in Progress.

   [COPSSPPI]  "Structure of Policy Provisioning Information (SPPI)",
               Work in Progress.

   [COPSCMS]   "COPS Over CMS", Work in Progress.

   [COPSTLS]   "COPS Over TLS", Work in Progress.

   [COPSGSS]   "COPS Extension for GSS-API based Authentication
               Support", Work in Progress.

   Other COPS & RSVP RFCs & drafts not listed as not directly relevant.

   Compliance: T==Total, P==Partial, F=Failed

   Section 1 - Per item discussion

   Initial Note: [COPSComp] claims "unconditional compliance" with all
   requirements.

   1.1 General Requirements

   1.1.1 Scalability - P (was T) The evaluator is concerned with
   scalability of many always-on TCP connections to a server supporting
   a lot of clients, particularly with the heartbeat messages.  The
   claim that the request handle is "unbounded" sounds fishy.

   1.1.2 Fail-over - P (was T) COPS gives an indication of peer failure,
   and has mechanisms to restart state, but there seems to be a bias
   toward a single state server.  COPS has decided that synchronizing
   state between multiple hot servers is out of scope.

   Because COPS uses TCP, it is at the mercy of the TCP timers of the
   implementation which can be significant.  Connection timeout
   reporting to the application may be delayed beyond the client
   authentication timeouts.  Tuning the Keep-Alive message to a tighter
   period will increase the session and system overhead.



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   1.1.3 Mutual Authentication - P (was T) The explanation is sort of
   for message object integrity.  It does not describe authentication
   techniques.  The evaluator assumes that COPS peers would authenticate
   each other at Client-Open time.  But cannot understand how this would
   work if proxies are involved.

   1.1.4 Transmission Level Security - T

   1.1.5 Data Object Confidentiality - T  Seems almost a carbon copy of
   the Diameter capabilities.  This evaluator echoes the high overhead
   concerns of the Diameter evaluator for the CMS capability.  TLS is
   not mentioned here, but is piled on later.

   1.1.6 Data Object Integrity - T  See above.

   1.1.7 Certificate Transport - T

   1.1.8 Reliable AAA Transport - T (maybe P) COPS meets this
   requirement as well as any other protocol we've evaluated.  That is
   it does have one application level ACK.  Statements such as "TCP
   provides guaranteed delivery" are incorrect.  COPS does attempt to
   identify outages by using a keep-alive message between TCP peers.

   1.1.9 Run over IPv4 - T

   1.1.10 Run over IPv6 - T

   1.1.11 Support Proxy and Routing Brokers - P (was T)  How client
   types are supported forward is not well understood by this evaluator.
   Does each client type require the Broker to make a different client
   Open request to it's upstream servers?  What about routing brokers?

   1.1.12 Auditability - P (was T)  (based on our interpretation as
   non-repudiation, rather than the definition given in reqts) The
   explanation of a History PIB is incomplete and therefore
   inconclusive.

   1.1.13 Shared Secret Not Required - T  Except this clause in
   [COPSAAA] 6.2 page 14 "COPS MUST be capable of supporting TLS"

   1.1.14 Ability to Carry Service Specific Attributes - P (was T)

   a) COPS only allows a small number of unique objects to be added.
      256 Object "classes" or types, with 256 subtypes or versions.
      Client types are 16 bits long, where the high bit indicates
      "enterprise" specific values.  But pertain to a COPS peer-





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      connection session.  The client type seems to just identify the
      information model for the message. eg. it will be fixed to one
      value for AAA.

   b) Service specific objects are not the same as Vendor Specific
      Objects.  They pertain to objects within a client type.

   c) The PIB model leads to a different model interoperability.
      Because most vendor product differ in some way, each PIB will be
      different, and sharing common provisioning profiles will be a
      rather difficult mapping problem on the server.

   d) It's not clear the different client types can be mixed or that
      other objects definitions can be used from other defined client
      types.  It's really unclear how the client type of a connection
      propagates in a proxy situation.

   1.2 Authentication Requirements

   1.2.1 NAI Support - T  The requirement that RFC 2459 (X.509 profiles)
   be met presumes that Auth servers would not have a mapping or local
   transformation.

   1.2.2 CHAP Support - T  An Information Model is being invoked, which
   I don't see really fleshed out anywhere.  [COPSAAA] does a bit of
   handwaving and definitions but doesn't deliver much meat.
   Nonetheless, this could be handled ala RADIUS.

   1.2.3 EAP Support - P (was T)  Again with the non-existent
   Information Model.  To do EAP, this evaluator thinks another Request
   or Decision type is needed here to indicate to proxies that an
   extended message exchange is in progress.

   1.2.4 PAP/Clear-text Passwords - T

   1.2.5 Reauthentication on demand - T

   1.2.6 Authorization w/o Authentication - T

   The comment "Please note: with existing algorithms, any authorization
   scheme not based on prior authentication is meaningless" is
   meaningless out of application context.

   1.3 Authorization Requirements

   1.3.1 Static and Dynamic IP Addr Assignment - T





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   1.3.2 RADIUS Gateway Capability - P (was T).  It would be interesting
   to see RADIUS attributes wrapped in some COPS "Information Model".

   1.3.3 Reject Capability - T

   1.3.4 Preclude Layer 2 Tunneling - T

   More work for the "Information Model" author!

   1.3.5 Reauthorization on Demand - T

   1.3.6 Support for Access Rules & Filters - P (was T)  Yet more work
   for the "Information Model" author, including some design issues
   which alluded the RADIUS and Diameter designers.  At least an attempt
   was made in Diameter.  There is nothing here.

   1.3.7 State Reconciliation - P (was T).  It is difficult for the
   evaluator to understand how well the COPS mechanisms work in a
   multi-administration situation, or in any proxy situation.  Multi-
   server coordination, if allowed, seems to be lacking a description.

   1.3.8 Unsolicited Disconnect - T

   1.4 Accounting Requirements

   1.4.1 Real Time Accounting - T

   1.4.2 Mandatory Compact Encoding - T  This evaluator does not believe
   that ADIF is a compact format.  But does believe that the Information
   Model author can design a PIB with accounting statistics that will
   satisfy this requirement.

   1.4.3 Accounting Record Extensibility - P (was T)  By defining a
   vendor/device specific PIB for additional elements.

   1.4.4 Batch Accounting - P (was T)  Offered description does not seem
   to match the requirement.

   1.4.5 Guaranteed Delivery - P (was T)  TCP does NOT "guarantee
   delivery", only application Acks can do that.  If these acks can be
   generated similar to the description here, then this requirement is
   met.









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   1.4.6 Accounting Timestamps - T  Another item for the "Information
   Model" author.

   1.4.7 Dynamic Accounting - T  Event and interim accounting can be
   supported.

   1.5 MOBILE IP Requirements

   1.5.1 Encoding of MOBILE IP Registration Messages - P (was T)  Yet
   more work for the "Information Model" author.  Hope he can handle it.

   1.5.2 Firewall Friendly - P (was T)  I guess.  Because it uses TCP
   and can be identified by known connection port.  But there is an
   issue with respect to the impact level of mixed COPS traffic coming
   through a common firewall port.

   1.5.3 Allocation of Local Home Agent - P (was T)  Just add another
   element to that "Information Model" definition.

   2. Summary Discussion

   COPS was designed to do some things similar to what we want and be
   somewhat flexible, but with a totally different set of assumptions on
   how many clients and requests would be funneled through the
   infrastructure and the acceptable overhead.  This evaluator is not
   sure that it scales well to the fast evolving access market where
   every product doesn't implement a small set of common features, but a
   large set of overlapping ones.

   3. General Requirements

   COPS started out with small and easily met set of design goals for
   RSVP and DiffServe, and is evolving as a new hammer to hit other
   nails [COPSPR].  As COPS implementors get more operational
   experience, it is interesting to see more reliability fixes/features
   quickly get patched in.

   Understanding COPS requires that you read a number RFCs and drafts
   which do not readily integrate well together.  Each application of
   COPS has spawned a number of drafts.  It's not clear if one wants to
   or can implement a single COPS server that can service AAA and other
   application clients.

   The COPS authors seem to overly believe in the goodness of TCP, and
   rely on it to solve all their transport problems, with concessions to
   application keep-alive messages to probe the connection status and
   sequence numbers to prevent replay attacks.  This evaluator believes
   this type of approach may work for many networks but really doesn't



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   scale well in larger configurations.  End-to-end application acks are
   the only guaranteed delivery solution, particularly where distributed
   state is involved.

   COPS falls into an in between place on encoding.  It has small number
   of simple data object blobs which are concatenated ala
   RADIUS/Diameter TLVs to form a flexible message layout.  However,
   they attempt to limit the number of objects by making them
   arbitrarily complex ala SNMP MIBs, and defining yet another data
   structuring language for these PIBs.  There is a lot of computer
   science style grandstanding in [COPSAAA] Section 1.2, but no
   translation into how a set of data objects can be used to meet these
   wonderful features in operation.  (or even if we needed them) This
   will be the crux of the interoperability issue.  RADIUS
   implementations interoperate because they at least, understand a
   common set of functional attributes from the RFCs.  And vendor extent
   ions can be simply customized in as needed via dictionaries.  If PIB
   definitions are needed for every piece and version of access
   equipment, before you can use it, then the bar for ease of
   configuration and use has been raised quite high.

   Support for PIB definition and vendor extensions will be on the same
   order as MIB integration in SNMP management products and put the
   supposed complexity of Diameter to shame.

   4. Summary Recommendation

   COPS has a structure that could be made to serve as a AAA protocol,
   perhaps by just copying the features of RADIUS and Diameter into it.
   The author of [COPSAAA] and [COPSComp] has not done the whole job yet
   and some of the missing pieces are vexing even for those already in
   the field.

   While some of the synergy with other COPS services is attractive,
   this evaluator is concerned about the liabilities of combining AAA
   services with the new emerging COPS applications in a single server
   entity will introduce more complexity than needed and opportunities
   to have progress pulled into other rat-holes. (eg. Policy Frameworks)













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Appendix D - Meeting Notes

   The minutes of the team meetings as recorded by various members.

D.1  Minutes of 22-Jun-2000 Teleconference

   Recorded by: Mark Stevens

   Arguments for and against SNMP as an AAA protocol were given.  Stuart
   Barkley gave a summary of the pro argument.  Mike St. Johns gave a
   summary of the con argument.  Dave Nelson asked for "instructions to
   the jury" in an effort to determine what evidence could and could not
   be used in making decisions.

   The AAA evaluation criteria is weak in some areas and in others it
   appears to be written with what might be interpreted as undue
   influence from the NASREQ working group.

   Mike St. Johns offered that we must restrict ourselves to considering
   only the evidence provided in the compliance documents and any
   supporting documents to which they may refer.

   In summary: AAA evaluation criteria document, AAA evaluation criteria
   source documents, protocol response documents and reference
   documents.

   The question as to what the group should do with malformed
   requirements came up.  The consensus seemed to be that we would use
   the requirements as adjusted in our last meeting where the
   requirements made no sense.

   The floor was then given to Stuart Barkley for the pro SNMP argument.

   Highlights:

   *  In most areas the requirements are met by SNMP.
   *  Confidentiality and Certificate transport mechanisms may be weak,
      but workable.
   *  With regard to Authentication, every technique can be supported
      although support for PAP or cleartext passwords is weak.
   *  With regard to Authorization, there is nothing in the requirements
      that cannot be supported.
   *  Accounting everything supported, although there is no specific
      consideration for compact encoding.  SNMP not as bloated as ASCII
      or XML based encoding schemes.  Requirement for compact encoding
      weakly indicated in requirements anyway.  Server-specific
      attributes needed, but compact encoding preclude w/o tradeoffs.




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   *  With regard to mobile IP requirement, everything works well,
      although firewall friendliness is a judgment call.
   *  Proxy mechanisms of SNMPv3 mitigates problems w/ firewalls.
   *  Scalability is ok.
   *  Overall, meets most requirements and shortfalls are minor.
   *  In some cases requirements seemed to expressed in a manner that
      "stacks" the odds against SNMP.
   *  SNMP is deployed everywhere already.

   *  The protocol has a well-understood behavior despite the tedium of
      MIB definition, so it has the advantage of not requiring the
      creation of a new infrastructure.
   *  AAA response document is silent on architecture and MIB
      definition, but there is too much work to do at this stage of
      evaluation.  Not having done the MIB definitions and architecture
      is not a limitation of the protocol.
   *  SNMP is a good candidate.

   Mike St. Johns took the floor to give a summary of the con argument.

   *  Neither the requirements, core documents nor response document
      specify the mechanism of operation.
   *  Liberties were taken in the assertion that the server to server
      interaction requirements were met.
   *  The scaling arguments are weak.
   *  Fail-over arguments are weak.
   *  Security aspects work well with the manager/server paradigm, but
      not well in bidirectional interactions among peers.
   *  The authentication requirements not understood by authors of the
      response document.  *  SNMP is just data moving protocol.
   *  Message formats not specified.
   *  What is the method for supporting authentication? Storing the
      information is handled, but what do the nodes do with it?

   *  The protocol certainly shined in the area of meeting accounting
      requirements.
   *  Although SNMP could certainly play a role in the accounting space,
      it is unusable in the areas of Authorization and Authentication.
   *  The response document does not address how the problem will be
      solved.
   *  It does not address the scalability issues that may arise in the
      transition from a manager-agent mode of operation to a client-
      server model.

   The group then examined each requirement against SNMP in a line-by-
   line exercise.





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D.2  Minutes of 27-Jun-2000 Teleconference

   Attendees - All (Mike St. John, Dave Mitton, Dave Nelson, Mark
   Stevens, Barney Wolff, Stuart Barkley, Steven Crain, Basavaraj Patil)

   Minutes recorded by : Basavaraj Patil

   Evaluation of RADIUS++ AAA Requirements

   Pro : Mark Stevens
   Con : Dave Nelson

   -  Question raised on if all meetings held so far have been recorded.
      Last week's meeting was recorded by Mark.  Previous meetings have
      been recorded by Mike.  All of these minutes should be available
      in the archive.

   -  Dave Nelson mentioned that Pat Calhoun has responded on the AAA WG
      mailing list to the changes made to the requirements document by
      the evaluation team.  Pat's response includes arguments for
      inclusion of some of the requirements that were deleted by the
      eval team.

   -  Mike concluded that we can reinstate these requirements after
      reviewing Pat's comments in detail and the RFCs referenced.  The
      intent is to take Pat's comments/document and review it between
      now and next Thursday (July 6th) and integrate the comments based
      on the findings at that time.

   Voting Procedure for evaluation : No voting during the discussion.
   All votes MUST be submitted to Mike by COB, June 28th, 00.

   -  Dave Nelson's summary of the Con statement for RADIUS++.
      Overview of the points on which the evaluator disagrees with the
      compliance statement.

      Conclusion from Dave : Not recommended (Details in the con
      statement).

      Q: Is it possible to use it for accounting?
      A: Authentication and Authorization could be separated, but
      Accounting is the weak link in this protocol and hence is not
      suitable.

   -  Mark Steven's summary of the Pro statement
      Agreed with most of the observations made by Dave Nelson.  The
      biggest thing going for it is that it has been running in this
      environment for a while and it does meet most of the requirements



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      in the document.  Transition will be easy and backwards
      compatibility is a key plus point.

   Point-by-point Discussion:

   General (1.1):

   1.1.1 Scalability

   BW - There is no actual limit on the number of outstanding requests.
   The protocol itself does not limit the number.

   DN -Simultaneous requests is not the same as outstanding requests.

   Discussion of workarounds that have been implemented to overcome this
   problem.

   1.1.2 Fail-over

   DN - This is an application layer protocol and uses application level
   time-outs to provide fail-over solutions.  Analogy and discussion on
   the use of round-trip-timer in TCP.

   Example of how robust a network can be based on a machine at MIT that
   was decommissioned and a new one with the same name installed in the
   network.

   Discussion of environments where proxies for primary, secondary and
   tertiaries exist and the possible effect of flooding messages in the
   event of a fail-over detection.

   1.1.3 Mutual Authentication

   No Discussion.  Accepted as stated.

   1.1.4 Transmission level security

   This requirement was deleted from the list by the evaluation team.
   It was deleted because it is an overgeneralization of Roam Ops.

   DN - There is a concern regarding what this really means.  Referred
   to what Pat is saying about this on the list and the need for it to
   be reinstated.

   Suggestion to change the tag in the requirements document to hop-by-
   hop security.





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   Does the Roamops group use transmission level security to imply hop-
   by-hop security?

   1.1.5 Data Object Confidentiality

   Mike explained the concept of Cryptographic Message Syntax (CMS -
   RFC2630).  There are some issues regarding the use of CMS at an end
   point.  Symmetric or Asymmetric keys can be used.

   There does not seem to be a problem with the suggested usage of CMS
   in RADIUS++.

   1.1.6/7 Data Object Integrity/Certificate Transport

   No discussion.  (I guess everyone concurs with the statement in the
   compliance document and the reviewers comments).

   1.1.8 Reliable AAA Transport

   BW - Radius provides reliability at the application layer by doing
   retransmissions.  So why is there a need for a reliable AAA transport
   protocol?

   - Is it packet loss that the protocol needs to be concerned about?

   DN - This requirement is tied to the failover issue.  Explanation of
   the negative impact of retransmissions in a network, especially in
   the case of a web of proxies.

   Conclusion is that this requirement deals with packet loss.

   1.1.9/10 Run over IPv4/6

   Running over IPv6 should be a trivial issue.

   1.1.11 Support Proxy and Routing Brokers

   -  Discussion on what this requirement means and analogy to DNS
      servers in a network.

   -  RADIUS can be extended to support this requirement and from the
      compliance document this does not appear to be fully cooked yet.

   1.1.12 Auditability

   No Discussion





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   1.1.13 Shared Secret Not Required

   This seems to be a trivial issue to be addressed in RADIUS++.

   1.1.14 Ability to carry Service Specific Attributes

   No Discussion

   Authentication Requirements:

   1.2.1 NAI Support

   Trivial - Total compliance.

   1.2.2 CHAP Support

   Comment : RADIUS support of CHAP could be better and the response
   needs to be encrypted.

   1.2.3/4 EAP/PAP

   No Discussion

   1.2.5 Reauthentication on Demand

   DN - Document claims that the server can reauthenticate by issuing an
   Access-challenge.  There is a change to the state machine and the
   suggested solution is too simplistic.  Also backwards compatibility
   would be an issue.

   1.2.6 Authorization w/o Authentication

   DN - This is trivial to fix, but this is not mentioned in the
   compliance document.

   Authorization Requirements:

   1.3.1 Static and Dynamic IP Addr assignment

   -  RADIUS does not rise to the demands of being a resource manager
   -  RADIUS assigns an address and it stays assigned for the session.
      There is no concept of leasing.

   1.3.2 RADIUS Gateway Capability

   This is a requirement written that is not applicable to RADIUS
   itself.




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   1.3.3/4/5/6/7/8

   Call dropped.  Somebody else needs to fill in here.  (Mike ????)

   Accounting Requirements:

   1.4.1 Real time accounting

   No dissent.  No discussion

   1.4.2 Mandatory compact encoding

   Comment made regarding ASN.1 and XML in this context

   1.4.3 Accounting Record Extensibility

   No discussion

   1.4.4 Batch Accounting

   No specific wording in the document to show how this can be done.
   Basically it is real time accounting without the real time
   constraint.

   It may be a trivial issue.

   1.4.5/6 Guaranteed Delivery/Accounting Timestamps

   No Discussion

   1.4.7 Dynamic Accounting

   There is ongoing discussion in the AAA WG on this requirement.  The
   RADIUS WG is also discussing this (comment).  The idea here is to be
   able to send the equivalent of a phonecall in progress type of
   messages.

   Mobile IP Requirements:

   1.5.1 Encoding of Mobile IP Reg. Messages

   May be trivial.  Discussion on what this requirement really is.  Is
   it just the ability to carry the reg. message as payload? Does the
   AAA protocol have to delve into the reg. message and behave
   differently.






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   1.5.2 Firewall Friendly

   No Discussion

   1.5.3 Allocation of Local Home Agents

   This concept needs to be clarified as the author writing the
   compliance statement did not understand it either.

   If you notice anything that I recorded here as something
   misinterpreted, please feel free to make corrections.

D.3  Minutes of 29-Jun-2000 Teleconference

   Attendees: Mike St. John, Dave Mitton, Dave Nelson, Barney Wolff,
   Stuart Barkley, Steven Crain, Basavaraj Patil.
   Missing: Mark Stevens.

   Minutes recorded by: Stuart Barkley

   Evaluation of Diameter AAA Requirements

   Advocates:

   Pro: Basavaraj Patil
   Con: Barney Wolff

   Summary discussion:

   PRO summary (Basavaraj Patil):

      session based
      lightweight base + extensions
      has implementation experience
      based upon radius
      fixes specific problems with radius,
      interoperates with radius
      looks like requirements are written for diameter

   CON summary (Barney Wolff):

      meets most needs, designed with requirements in mind

   issues:  scalability in small devices (strong crypto specifically)

      failover (need guidance on failover recovery procedures)





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      Data object confidentiality has been expressed as very important,
      diameter glosses over it referring to rfc2630, cost to run on NAS
      device

      ACL: filter style syntax seems inadequate

      state reconciliation: difficult over global multiple
      administrative domains

      batch accounting: implementation doesn't meet intended need

      firewall friendly: until firewalls support SCTP will be failure

   summary very close

   concerns:

   size and complexity needs almost all extensions to actually support
   needs separation of SCTP and data (as per IESG suggestion?)
   application vs transport acks

   Point-by-point Discussion:

   General (1.1):

   1.1.1 Scalability

      Handles large number of requests

      SCTP reduces proxy needs (how? what is justification for this
      statement?)

      Scalability in large

   1.1.2 Fail-over

      Recovery from SCTP failure needs discussion (Note to DM: Include
      in final document considerations)

   1.1.3 Mutual Authentication

      No Discussion

   1.1.4 Transmission level security

      No Discussion





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   1.1.5/6 Data Object Confidentiality/Data Object Integrity

      Crypto in NAS
      NAS needs knowledge of when to use crypto
      One Time Passwords

   1.1.7 Certificate Transport

      No Discussion

   1.1.8 Reliable AAA Transport

      No Discussion

   1.1.9/10 Run over IPv4/6

      No Discussion

   1.1.11 Support Proxy and Routing Brokers

      No Discussion

   1.1.12 Auditability

      No Discussion

   1.1.13 Shared Secret Not Required

      No Discussion

   1.1.14 Ability to carry Service Specific Attributes

      No Discussion

   Authentication Requirements:

   1.2.1 NAI Support

      No Discussion

   1.2.2 CHAP Support

      No Discussion

   1.2.3/4 EAP/PAP

      No Discussion




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   1.2.5 Reauthentication on Demand

      No Discussion

   1.2.6 Authorization w/o Authentication

      No Discussion

   Authorization Requirements:

   1.3.1 Static and Dynamic IP Addr assignment

      No Discussion

   1.3.2 RADIUS Gateway Capability

      Protocol requirement or implementation/application requirement?
      Which RADIUS versions are to be supported?  Which subset?

   1.3.3 Reject Capability

      No Discussion

   1.3.4 Preclude L2TP

      No Discussion

   1.3.5 Reauthorize on demand

      Raj to look at this again

   1.3.6 Support for ACLs

      Standardizes syntax not semantics.
      Standardizes semantics in NASREQ extension, but is very weak

   1.3.7 State reconciliation

      Appears to be weak in that server must "query the world" to
      restore its state
      Just in time reconciliation
      Simultaneous usage limitations
      More discussion needed








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   1.3.8 Unsolicited disconnect

      No Discussion

   Accounting Requirements:

   1.4.1 Real time accounting

      No Discussion

   1.4.2 Mandatory compact encoding

      Is ADIF compact?
      Is ADIF UTF-8 compatible?

   1.4.3 Accounting Record Extensibility

      No Discussion

   1.4.4 Batch Accounting

      Diameter okay for small batches.  Specification doesn't seem
      suitable for large batch transfers (100,000+ records)

   1.4.5 Guaranteed Delivery

      No Discussion

   1.4.6 Accounting Timestamps

      No Discussion

   1.4.7 Dynamic Accounting

      No Discussion

   Mobile IP Requirements:

   1.5.1 Encoding of Mobile IP Reg. Messages

      Taken of faith

   1.5.2 Firewall Friendly

      Issues with SCTP being supported initially through firewalls






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   1.5.3 Allocation of Local Home Agents

      Still lack of understanding of the AAA protocol requirements here
      (versus just being a roaming attribute)

   Overall summary:

   Diameter seems to meet most requirements and is a likely candidate to
   support AAA requirements.

   Other matters:

   Votes on Diameter should be in by Sunday evening.  Same format as
   before.  Mike will tally up as both majority and average votes.

   Should different requirements have different weight?

   Possibility of SNMP reconsideration as per ADs?  To close off our
   task in timeframe allocated, should not reopen submissions or
   discussions.  Could cause to drag on for long time causing us to miss
   our July 15 date.

   Possibility of needing a few extra days to finish report due to
   editing and review needs of the group.  Mike to ask ADs to consider
   slight time extension possibility.

   "No discussion" means that the topic was mentioned but there we no
   objections/issues raised on that requirement being met.

   These are based upon my notes.  Please send any corrections to the
   list.

D.4  Minutes of 06-Jul-2000 Teleconference

   Minutes of AAA-Team Telecon 7/6/00
   By: Barney Wolff

   Pro review of COPS - Dave Nelson

      Likes the object model.
      No apparent showstoppers.
      Will resend review with typos corrected.









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   Con review of COPS - Dave Mitton

      Architecture is mostly there.
      Strong dependency on info model, sceptical of object model.
      Problem with info model in multi-vendor, multi-administration
      environment.
      How does server speak to multiple client flavors?
      Will resend review with typos corrected.

   Comment by Mike StJ "replace SNMP with COPS" - :) I think.

   Per-Item discussion

   1.1.1 Scalability - concern re always-on TCP.  Direction to DM - add
   general issue of number of connections.

   1.1.2 Failover - No hot backup, but true of all protocols.  (ie, no
   explicit mention of server-server protocol that might keep a backup
   server in sync so it could take over instantly.)

   1.1.3 Mutual Authentication - perhaps relies on TLS.  Draft does not
   otherwise support this.

   1.1.8 Reliable AAA Transport - TCP + appl heartbeat.

   1.1.11 Proxy & Routing Brokers - client-type interaction with proxy
   is questionable.  (In later discussion, it appears client-type is a
   field in the request, and perhaps all AAA is one type, so may not be
   an issue.)

   1.1.13 Shared secret not req'd - runs over TLS, no multiple levels of
   security.

   1.2.1 NAI Support - some uncertainty on the impact of RFC 2459 (X.509
   profiles) on this - may restrict NAI in some way?

   1.2.3 EAP Support - multi-pass handshake needs work.

   1.2.6 Authorization without Authentication - Mike comments the
   requirement is broken.  BW comment (post-meeting) - the requirement
   appears intended specifically to chastise RADIUS for requiring User-
   Name and some sort of password in an Access-Request, even if it's
   sent pre-connect, on receipt of DNIS, for example.  Sure it's silly,
   but does it really matter whether an attribute is absent or filled
   with "NONE"?  This was just nasty sniping at RADIUS on somebody's
   part, imho.

   1.3.2 RADIUS Gateway - skepticism was expressed.



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   1.3.4 Preclude L2 Tunnels - too much handwaving.

   1.3.6 Access Rules - lots of work needed.

   1.3.7 State Reconciliation - multi-server coordination is an issue.

   1.4.4 Batch Accounting - for small batches, perhaps.

   1.4.5 Guaranteed Delivery - application acks are an area of mystery.

   1.5.2 Firewall-Friendly - COPS like any Swiss-Army-Knife protocol
   (SNMP) requires the firewall to look inside the packets, because
   passing AAA may be allowed but not other protocol uses.  So it would
   be a big help, for both COPS and SNMP, to define a different port for
   its AAA application.

D.5  Minutes of 11-Jul-2000 Teleconference

   Present:  Mike, Bernard, Paul, Bert, Raj, Dave N., Dave M., Barney,
   Stuart, Mark
   Recorded By: Dave Nelson

   Mike St. Johns set the ground rules.

   An item by item review of the summary results was held.

   1.1.1 Question as to why SNMP and RADIUS++ are "P"?  There are issues
   regarding scaling of retries in a web of proxies (multi-layer proxy;
   primary, secondary tertiary servers at each level).

   1.1.2 No protocol did very well.  Similar issues as above, e.g. web
   of proxies.  Recovery of state from a previously failed primary
   server?

   1.1.3 Question as to how serious is the need for this requirement?
   May be some legitimate requirements from Mobile IP.  Is this
   requirement an AAA-level issue?

   1.1.4 Called hop-by-hop or transmission level?

   1.1.5 Most protocols evaluated used CMS to meet this requirement.
   Question as to applicability of CMS for NASes and other edge devices?
   There is a requirement for object by object confidentiality.
   consider three-party scenarios.







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   1.1.6 Question as to why SNMP did not rate the same as for item
   1.1.5?  The evaluation is based on what was contained in the
   submission documents, rather than capabilities of the protocol
   itself.  Too much hand waving.

   1.1.7 No comments.

   1.1.8 Question as to meaning of "reliable"?  Discussion of transport
   protocols was deferred to later in the meeting.

   1.1.9 No comments.

   1.1.10 SNMP received "P" because of hand waving in the submission
   documents.

   1.1.11 SNMP received "F" because this section of the submission
   document indicated "t.b.d.".  Diameter was the only protocol
   submission to completely address this item.

   1.1.12 We treated this requirement as "non-repudiation".  There is a
   concern that digital signatures are computationally expensive and are
   not globally available.  COPS has more work to do on this item.

   1.1.13 Question that "no shared secrets" should be interpreted to
   mean that an alternative key management mechanism is available?  We
   treated this as meaning that application-layer security could be
   turned off in deference to transport layer security.  There had been
   discussion of the use of IKE in the AAA protocol.

   1.1.14 No comments.

   1.2.1 No comments.

   1.2.2 No comments.

   1.2.3 No comments.

   1.2.4 Is there a need for a clear-text "password" for service such as
   OTP, SecurID, et. al.?   It was noted that all plain passwords are
   exposed in clear-text at the NAS or other edge device, which is no
   more inherently trustworthy than any AAA server or proxy.

   1.2.5 We distinguished event-driven reauthentication from timer-
   driven (or lifetime-driven).  How is this requirement to be met in a
   proxy environment?

   1.2.6 We asserted that this requirement is an oxymoron.




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   1.3.1 We had difficulty in determining what "static" meant, and from
   which reference point it was measured.

   1.3.2 We agreed that NAIs could be handled, possibly with some
   restrictions.

   1.3.3 No comment.

   1.3.4 The SNMP submission documents contained significant hand
   waving.

   1.3.5 Similar comments as to item 1.2.5.  The question was raised as
   to how the server knows when to send this request?

   1.3.6 We found that the notation in Diameter was weak, and of a least
   common denominator nature.  In general, there was concern about
   achieving interoperability when the syntax was standardized but the

   semantics were not.  This area needs further work.

   1.3.7 Question as to how this requirement is achieved via proxies?

   1.4.1 No comment.

   1.4.2 No comment.

   1.4.3 No comment.

   1.4.4 There was significant skepticism regarding batch accounting as
   part of the AAA protocol.  How large are the "batches"?  Should this
   requirement be met using FTP or something similar?

   1.4.5 No comment.

   1.4.6 No comment.

   1.4.7 No comment.

   1.5.1 No comment.

   1.5.2 There was some discussion of what constitutes firewall
   friendly.  It was suggested that the firewall didn't want to look
   into packets much past the application protocol address (e.g. UDP or
   TCP port number).  Protocols such as SNMP and COPS that have usage
   other than AAA are at a disadvantage, since the firewall must look
   deep into the application PDU to determine the intended purpose of
   the packet.  Diameter suffers from reliance of SCTP, which is not
   widely deployed or widely recognized by firewalls.  Should firewalls



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   also be AAA proxy engines?  Has this issue anything to do with
   interoperability with NAT?

   1.5.3 We had some confusion as to what the requirement actually was.
   Raj seemed to be able to explain it, but the rest of us had to take
   it on faith.

   A poll was taken on overall acceptability and effort for each of the
   protocols submitted, for requirements conformance.

   Each member indicated their evaluation in the form of (Acceptable,
   Not-Acceptable) with qualifiers for (Accounting, or effort to change)
   This information will be summarized in the final report.

   A general wrap-up discussion was held.

   It was considered important that as much of the thought processes and
   rationales be placed in the final report as is feasible.  Mike St.
   John will work with Dave Mitton on the ID.  We really need to meet
   the IETF July 14 submission deadline, even if we have to issue an
   update on the AAA WG mailing list.  All agreed that the process went
   fairly well.  In future evaluations of this nature, it would be well
   for the evaluators to follow the requirements documents closely, for
   the submitters to create accurate and complete conformance documents,
   and to allow a "re-spin" cycle to correct errors and omissions in the
   requirements documents and conformance documents.

   A discussion of the transport protocol was held.

   The issue with transport is congestion control.  There has been a
   problem with streams-oriented applications over TCP.  The IESG is
   increasingly sensitive to this issue in new protocols.  It was noted
   that AAA was a transaction-oriented application.  Other request-
   response applications, such as DNS, seem to scale welt to Internet-
   scale using simple application-level retries and UDP transport.  TCP
   has problems with head-of-line blocking, especially when multiple
   sessions are using a single TCP connection.  AAA typically will send
   3 or 4 iterations and then indicate a failure to the upper layers.
   It won't continue retransmissions in the face of congestion, like
   TCP.  It was noted that bulk data transfer may not best be
   implemented in the AAA protocol.  Concern was voiced that SCTP is not
   a widely implemented protocol.  AAA will implement congestion control
   by limiting the number of outstanding requests.  Some RADIUS
   implementations send lots of traffic when they encounter
   misconfigured shared secrets, but this is likely caused by a lack of
   proper error recovery.  Diameter, as currently drafted, relies on
   SCTP.  Can AAA run over UDP?  The IESG didn't say "no"; their issue
   is addressing congestion control.



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Full Copyright Statement

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

   This document and translations of it may be copied and furnished to
   others, and derivative works that comment on or otherwise explain it
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   The limited permissions granted above are perpetual and will not be
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   This document and the information contained herein is provided on an
   "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING
   TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING
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   HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF
   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.

Acknowledgement

   Funding for the RFC Editor function is currently provided by the
   Internet Society.



















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