path: root/doc/rfc/rfc7391.txt

Internet Engineering Task Force (IETF)                     J. Hadi Salim
Request for Comments: 7391                             Mojatatu Networks
Updates: 5810, 7121                                         October 2014
Category: Standards Track
ISSN: 2070-1721


 Forwarding and Control Element Separation (ForCES) Protocol Extensions

Abstract

   Experience in implementing and deploying the Forwarding and Control
   Element Separation (ForCES) architecture has demonstrated the need
   for a few small extensions both to ease programmability and to
   improve wire efficiency of some transactions.  The ForCES protocol is
   extended with a table range operation and a new extension for error
   handling.  This document updates the semantics in RFCs 5810 and 7121
   to achieve that end goal.

Status of This Memo

   This is an Internet Standards Track document.

   This document is a product of the Internet Engineering Task Force
   (IETF).  It represents the consensus of the IETF community.  It has
   received public review and has been approved for publication by the
   Internet Engineering Steering Group (IESG).  Further information on
   Internet Standards is available in Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7391.

Copyright Notice

   Copyright (c) 2014 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.




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Table of Contents

   1. Introduction ....................................................2
      1.1. Terminology and Conventions ................................3
           1.1.1. Requirements Language ...............................3
           1.1.2. Terminology .........................................3
   2. Problem Overview ................................................4
      2.1. Table Ranges ...............................................4
      2.2. Error Codes ................................................4
   3. Protocol Update .................................................5
      3.1. Table Ranges ...............................................5
      3.2. Error Codes ................................................6
           3.2.1. New Codes ...........................................7
           3.2.2. Private Vendor Codes ................................8
           3.2.3. Extended Result TLV .................................8
                  3.2.3.1. Extended Result Backward Compatibility .....9
      3.3. Large Table Dumping ........................................9
   4. IANA Considerations ............................................11
   5. Security Considerations ........................................12
   6. References .....................................................12
      6.1. Normative References ......................................12
      6.2. Informative References ....................................12
   Appendix A. New FEPO Version ......................................13
   Acknowledgments ...................................................23
   Author's Address ..................................................23

1.  Introduction

   Experience in implementing and deploying the ForCES architecture has
   demonstrated the need for a few small extensions both to ease
   programmability and to improve wire efficiency of some transactions.
   This document describes a few extensions to the semantics in the
   ForCES protocol specification [RFC5810] to achieve that end goal.

   This document describes and justifies the need for two small
   extensions that are backward compatible.  This document also
   clarifies details of how dumping of a large table residing on an FE
   (Forwarding Element) is achieved.  To summarize:

   1.  A table range operation to allow a controller or control
       application to request an arbitrary range of table rows is
       introduced.

   2.  Additional error codes returned to the controller (or control
       application) by an FE are introduced.  Additionally, a new
       extension to carry details on error codes is introduced.  As a
       result, this document updates the definition of the FE Protocol
       Object (FEPO) Logical Functional Block (LFB) in [RFC7121].



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   3.  While already supported, an FE response to a GET request of a
       large table that does not fit in a single Protocol Layer (PL)
       message is not described in [RFC5810].  This document clarifies
       the details.

1.1.  Terminology and Conventions

1.1.1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

1.1.2.  Terminology

   This document reiterates the terminology defined in several ForCES
   documents ([RFC3746], [RFC5810], [RFC5811], and [RFC5812]) for the
   sake of contextual clarity.

      Control Element (CE)

      Forwarding Element (FE)

      FE Model

      LFB (Logical Functional Block) Class (or type)

      LFB Instance

      LFB Model

      LFB Metadata

      ForCES Component

      LFB Component

      ForCES Protocol Layer (ForCES PL)

      ForCES Protocol Transport Mapping Layer (ForCES TML)











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2.  Problem Overview

   In this section, we present sample use cases to illustrate each
   challenge being addressed.

2.1.  Table Ranges

   Consider, for the sake of illustration, an FE table with 1 million
   reasonably sized table rows that are sparsely populated.  Assume,
   again for the sake of illustration, that there are 2000 table rows
   sparsely populated between the row indices 23-10023.

   Implementation experience has shown that existing approaches for
   retrieving or deleting a sizable number of table rows are both
   programmatically tedious and inefficient on utilization of both
   compute and wire resources.

   By definition, ForCES GET and DEL requests sent from a controller (or
   control application) are prepended with a path to a component and
   sent to the FE.  In the case of indexed tables, the component path
   can point to either a table or a table row index.

   As an example, a control application attempting to retrieve the first
   2000 table rows appearing between row indices 23 and 10023 can
   achieve its goal in one of the following ways:

   o  Dump the whole table and filter for the needed 2000 table rows.

   o  Send up to 10000 ForCES PL requests, incrementing the index by one
      each time, and stop when the needed 2000 entries are retrieved.

   o  If the application had knowledge of which table rows existed (not
      unreasonable given the controller is supposed to be aware of state
      within a Network Element (NE)), then the application could take
      advantage of ForCES batching to send fewer large messages (each
      with different path entries for a total of 2000).

   As argued, while the above options exist, all are tedious.

2.2.  Error Codes

   [RFC5810] has defined a generic set of error codes that are to be
   returned to the CE from an FE.  Deployment experience has shown that
   it would be useful to have more fine-grained error codes.  As an
   example, the error code E_NOT_SUPPORTED could be mapped to many FE
   error source possibilities that need to then be interpreted by the
   caller based on some understanding of the nature of the sent request.
   This makes debugging more time consuming.



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3.  Protocol Update

   This section describes a normative update to the ForCES protocol to
   address the issues discussed in Section 2.

3.1.  Table Ranges

   We define a new TLV, TABLERANGE-TLV (type ID 0x0117), that will be
   associated with the PATH-DATA-TLV in the same manner the KEYINFO-TLV
   is.  Figure 1 shows how this new TLV is constructed.

      0                   1                   2                   3
      0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |  Type (0x0117)              |     Length                      |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         Start Index                           |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |                         End Index                             |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                Figure 1: ForCES Table Range Request Layout

   Figure 2 illustrates a GET request for a range of rows 11 to 23 of a
   table with a component path of "1/6".

      OPER = GET-TLV
             PATH-DATA-TLV:
               flags = F_SELTABRANGE, IDCount = 2, IDs = {1,6}
               TABLERANGE-TLV content = {11,23}

               Figure 2: ForCES Table Range Request Example

   The path flag F_SELTABRANGE (0x2, i.e., bit 1, where bit 0 is
   F_SELKEY as defined in [RFC5810]) MUST be set to indicate the
   presence of the TABLERANGE-TLV.  The path flag bit F_SELTABRANGE can
   only be used in a GET or DEL and is mutually exclusive with F_SELKEY.
   The FE MUST enforce the path flag constraints and ensure that the
   selected path belongs to a defined, indexed table component.  Any
   violation of these constraints MUST be rejected with an error code of
   E_INVALID_TFLAGS with a description of what the problem is when using
   extended error reporting (refer to Section 3.2).

   It should be noted that there are combinations of path selection
   mechanisms that should not appear together for the sake of simplicity
   of operations.  These include TABLERANGE-TLV and KEYINFO-TLV as well
   as multiple nested TABLERANGE-TLVs.




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   The TABLERANGE-TLV contents constitute:

   o  A 32-bit start index.  An index of 0 implies the beginning of the
      table row.

   o  A 32-bit end index.  A value of 0xFFFFFFFF implies the last entry.

   The response for a table range query will either be:

   o  The requested table data returned (when at least one referenced
      row is available); in such a case, a response with a path pointing
      to the table and whose data content contains the row(s) will be
      sent to the CE.  The data content MUST be encapsulated in a
      SPARSEDATA-TLV.  The SPARSEDATA-TLV content will have the "I" (in
      Index-Length-Value (ILV)) for each table row indicating the table
      indices.

   o  An EXTENDEDRESULT-TLV (refer to Section 3.2.3) when:

      *  the response is to a range delete request.  The result will
         either be:

         +  a success if any of the rows that were requested are
            deleted; or

         +  a proper error code if none of the rows that were requested
            can be deleted.

      *  data is absent and an error code of E_EMPTY with an optional
         content string describing the nature of the error is used
         (refer to Section 3.2).

      *  both a path key and path table range were stated on the path
         flags of the original request.  In such a case, an error code
         of E_INVALID_TFLAGS with an optional content string describing
         the nature of the error is used (refer to Section 3.2).

      *  other standard ForCES errors (such as Access Control List (ACL)
         constraints trying to retrieve contents of an unreadable table,
         accessing unknown components, etc.) occur.

3.2.  Error Codes

   We define the following:

   1.  A new set of error codes.

   2.  Allocation of some reserved codes for private use.



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   3.  A new TLV, EXTENDEDRESULT-TLV (0x0118), that will carry a code
       (which will be a superset of what is currently specified in
       [RFC5810]) as well as an optional cause content.  This is
       illustrated in Figure 3.

3.2.1.  New Codes

   The EXTENDEDRESULT-TLV Result Value is 32 bits and is a superset of
   the RESULT-TLV Result Value defined in [RFC5810].  The new version
   code space is 32 bits as opposed to the code size of 8 bits in
   [RFC5810].  The first 8-bit values (256 codes) are common to both
   code spaces.

   +------------+-------------------------+----------------------------+
   | Code       | Mnemonic                | Details                    |
   +------------+-------------------------+----------------------------+
   | 0x18       | E_TIMED_OUT             | A timeout occurred while   |
   |            |                         | processing the message     |
   |            |                         |                            |
   | 0x19       | E_INVALID_TFLAGS        | Invalid table flags        |
   |            |                         |                            |
   | 0x1A       | E_INVALID_OP            | Requested operation is     |
   |            |                         | invalid                    |
   |            |                         |                            |
   | 0x1B       | E_CONGEST_NT            | Node congestion            |
   |            |                         | notification               |
   |            |                         |                            |
   | 0x1C       | E_COMPONENT_NOT_A_TABLE | Component not a table      |
   |            |                         |                            |
   | 0x1D       | E_PERM                  | Operation not permitted    |
   |            |                         |                            |
   | 0x1E       | E_BUSY                  | System is busy             |
   |            |                         |                            |
   | 0x1F       | E_EMPTY                 | Table is empty             |
   |            |                         |                            |
   | 0x20       | E_UNKNOWN               | A generic catch-all error  |
   |            |                         | code.  Carries a string to |
   |            |                         | further extrapolate what   |
   |            |                         | the error implies.         |
   +------------+-------------------------+----------------------------+

                            Table 1: New Codes









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3.2.2.  Private Vendor Codes

   Codes 0x100-0x200 are reserved for use as private codes.  Since these
   are freely available, it is expected that the FE and CE side
   implementations will both understand/interpret the semantics of any
   used codes and avoid any conflicts.

3.2.3.  Extended Result TLV

        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   Type = EXTENDEDRESULT-TLV   |              Length           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                        Result Value                           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                    Optional Cause Content                     |
       .                                                               .
       |                                                               |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                       Figure 3: EXTENDEDRESULT-TLV

   o  Like all other ForCES TLVs, the EXTENDEDRESULT-TLV is expected to
      be 32-bit aligned.

   o  The EXTENDEDRESULT-TLV Result Value derives and extends from the
      same current namespace that is used by the RESULT-TLV Result Value
      as specified in Section 7.1.7 of [RFC5810].  The main difference
      is that there is now a 32-bit Result Value (as opposed to the old
      8-bit).

   o  The Optional Cause Content is defined to further disambiguate the
      Result Value.  It is expected that UTF-8 string values will be
      used.  The content Result Value is intended to be consumed by the
      (human) operator, and implementations may choose to specify
      different content for the same error code.  Additionally, future
      codes may specify cause content to be of types other than string.

   o  It is recommended that the maximum size of the cause string should
      not exceed 32 bytes.  The cause string is not standardized by this
      document.









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3.2.3.1.  Extended Result Backward Compatibility

   To support backward compatibility, we update the FEPO LFB (in
   Appendix A) to version 1.2.  We also add a new component ID 16 (named
   EResultAdmin), and a capability component ID 32 (named EResultCapab).

   An FE will advertise its capability to support extended TLVs via the
   EResultCapab table.  When an FE is capable of responding with both
   extended results and older result TLVs, it will have two table rows,
   one for each supported value.  By default, an FE capable of
   supporting both modes will assume the lowest common denominator
   (i.e., EResultAdmin will be EResultNotSupported) and will issue
   responses using RESULT-TLVs.  It should be noted that an FE
   advertising FEPO version 1.2 MUST support EXTENDEDRESULT-TLVs at
   minimum.

   On an FE that supports both RESULT-TLVs and EXTENDEDRESULT-TLVs, a
   master CE can turn on support for extended results by setting the
   EResultAdmin value to 2, in which case the FE MUST switch over to
   sending only EXTENDEDRESULT-TLVs.  Likewise, a master CE can turn off
   extended result responses by writing a 1 to the EResultAdmin.  An FE
   that does not support one mode or the other MUST reject setting
   EResultAdmin to a value it does not support by responding with an
   error code of E_NOT_SUPPORTED.  It is expected that all CEs
   participating in a high availability (HA) mode be capable of
   supporting FEPO version 1.2 whenever EResultAdmin is set to strict
   support of EXTENDEDRESULT-TLVs.  The consensus between CEs in an HA
   set up to set strict support of EXTENDEDRESULT-TLVs is out of scope
   for this document.

3.3.  Large Table Dumping

   Imagine a GET request to a path that is a table, i.e., a table dump.
   Such a request is sent to the FE with a specific correlator, say X.
   Imagine this table to have a large number of entries at the FE.  For
   the sake of illustration, let's say millions of rows.  This requires
   that the FE delivers the response over multiple messages, all using
   the same correlator X.

   The ForCES protocol document [RFC5810] does not adequately describe
   how a large multi-part GET response message is delivered; the text in
   this section clarifies.  We limit the discussion to a table object
   only.

   Implementation experience of dumping large tables shows that we can
   use transaction flags to indicate that a GET response is the
   beginning, middle, or end of a multi-part message.  In other words,
   we mirror the effect of an atomic transaction sent by a CE to an FE.



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       CE PL                                                  FE PL

         |                                                      |
         | (0) Query, Path-to-a-large-table, OP=GET             |
         |----------------------------------------------------->|
         |                correlator = X                        |
         |                                                      |
         | (1) Query-Response, SOT,AT, OP=GET-RESPONSE, DATA    |
         |<-----------------------------------------------------|
         |                correlator = X                        |
         |             DATA TLV (SPARSE/FULL)                   |
         |                                                      |
         | (2) Query-Response, MOT,AT, OP=GET-RESPONSE, DATA    |
         |<-----------------------------------------------------|
         |                correlator = X                        |
         |             DATA TLV (SPARSE/FULL)                   |
         |                                                      |
         | (3) Query-Response, MOT,AT, OP=GET-RESPONSE, DATA    |
         |<-----------------------------------------------------|
         |                correlator = X                        |
         |             DATA TLV (SPARSE/FULL)                   |
         .                                                      .
         .                                                      .
         .                                                      .
         .                                                      .
         |                                                      |
         | (N) Query-Response, MOT,AT, OP=GET-RESPONSE, DATA    |
         |<-----------------------------------------------------|
         |                correlator = X                        |
         |             DATA TLV (SPARSE/FULL)                   |
         |                                                      |
         | (N) Query-Response, EOT,AT, OP=GET-RESPONSE          |
         |<-----------------------------------------------------|
         |                correlator = X                        |
         |             RESULT-TLV (SUCCESS)                     |
         |                                                      |

                 Figure 4: Large Table Dump Time Sequence

   The last message to go to the CE, which carries the End Of
   Transaction (EOT) flag, MUST NOT carry any data.  This allows us to
   mirror ForCES two-phase commit (2PC) messaging [RFC5810] where the
   last message is an empty commit message.  A GET response will carry a
   RESULT-TLV in such a case.







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4.  IANA Considerations

   This document updates <https://www.iana.org/assignments/forces>
   as follows:

   This document registers two new top-level TLVs and two new path
   flags; it also updates an IANA-registered FE Protocol Object Logical
   Functional Block (LFB).

   Appendix A defines an update to the FE Protocol Object LFB to
   version 1.2.  An entry for FE Protocol Object LFB version 1.2 has
   been added to the "Logical Functional Block (LFB) Class Names and
   Class Identifiers" sub-registry.

   The following new TLVs have been defined and added to the "TLV Types"
   sub-registry:

   o  TABLERANGE-TLV (type ID 0x0117)

   o  EXTENDEDRESULT-TLV (type ID 0x0118)

   The "RESULT-TLV Result Values" sub-registry has been updated
   as follows:

   o  Codes 0x21-0xFE are marked as Unassigned.

   o  Codes 0x18-0x20 are defined by this document in Section 3.2.1.

   o  Codes 0x100-0x200 are reserved for private use.

   A new "EXTENDEDRESULT-TLV Result Values" sub-registry has been
   created.  The codes 0x00-0xFF are mirrored from the "RESULT-TLV
   Result Values" sub-registry.  Any future allocations of this code
   range (in the range 0x21-0xFE) must be made only in the new
   "EXTENDEDRESULT-TLV Result Values" sub-registry and not in the
   "RESULT-TLV Result Values" sub-registry.  The codes 0x100-0x200 are
   reserved for private use as described earlier, and the code ranges
   0x21-0xFE and 0x201-0xFFFFFFFF are marked as Unassigned with the IANA
   allocation policy of Specification Required [RFC5226].  The
   Designated Expert (DE) needs to ensure that existing deployments are
   not broken by any specified request.  The DE should post a given code
   request to the ForCES WG mailing list (or a successor designated by
   the Area Director) for comment and review.  The DE should then either
   approve or deny the registration request, publish a notice of the
   decision to the ForCES WG mailing list or its successor, and inform
   IANA of his/her decision.  A denial notice must be justified by an





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   explanation and, in the cases where it is possible, concrete
   suggestions on how the request can be modified so as to become
   acceptable.

5.  Security Considerations

   The security considerations described in the ForCES protocol
   [RFC5810] apply to this document as well.

6.  References

6.1.  Normative References

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC5226]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", BCP 26, RFC 5226,
              May 2008, <http://www.rfc-editor.org/info/rfc5226>.

   [RFC5810]  Doria, A., Hadi Salim, J., Haas, R., Khosravi, H., Wang,
              W., Dong, L., Gopal, R., and J. Halpern, "Forwarding and
              Control Element Separation (ForCES) Protocol
              Specification", RFC 5810, March 2010,
              <http://www.rfc-editor.org/info/rfc5810>.

   [RFC5811]  Hadi Salim, J. and K. Ogawa, "SCTP-Based Transport Mapping
              Layer (TML) for the Forwarding and Control Element
              Separation (ForCES) Protocol", RFC 5811, March 2010,
              <http://www.rfc-editor.org/info/rfc5811>.

   [RFC5812]  Halpern, J. and J. Hadi Salim, "Forwarding and Control
              Element Separation (ForCES) Forwarding Element Model",
              RFC 5812, March 2010, <http://www.rfc-editor.org/
              info/rfc5812>.

   [RFC7121]  Ogawa, K., Wang, W., Haleplidis, E., and J. Hadi Salim,
              "High Availability within a Forwarding and Control Element
              Separation (ForCES) Network Element", RFC 7121,
              February 2014, <http://www.rfc-editor.org/info/rfc7121>.

6.2.  Informative References

   [RFC3746]  Yang, L., Dantu, R., Anderson, T., and R. Gopal,
              "Forwarding and Control Element Separation (ForCES)
              Framework", RFC 3746, April 2004,
              <http://www.rfc-editor.org/info/rfc3746>.



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Appendix A.  New FEPO Version

   This version of FEPO updates the earlier one given in [RFC7121].  The
   XML has been validated against the schema defined in [RFC5812].

  <LFBLibrary xmlns="urn:ietf:params:xml:ns:forces:lfbmodel:1.0"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:noNamespaceSchemaLocation="lfb-schema.xsd" provides="FEPO">
     <!-- XXX -->
     <dataTypeDefs>
        <dataTypeDef>
           <name>CEHBPolicyValues</name>
           <synopsis>
              The possible values of CE heartbeat policy
           </synopsis>
           <atomic>
              <baseType>uchar</baseType>
              <specialValues>
                 <specialValue value="0">
                    <name>CEHBPolicy0</name>
                    <synopsis>
                        The CE will send heartbeats to the FE
                        every CEHDI timeout if no other messages
                        have been sent since.
                    </synopsis>
                 </specialValue>
                 <specialValue value="1">
                    <name>CEHBPolicy1</name>
                    <synopsis>
                        The CE will not send heartbeats to the FE.
                    </synopsis>
                 </specialValue>
              </specialValues>
           </atomic>
        </dataTypeDef>
        <dataTypeDef>
           <name>FEHBPolicyValues</name>
           <synopsis>
               The possible values of FE heartbeat policy
           </synopsis>
           <atomic>
              <baseType>uchar</baseType>
              <specialValues>
                 <specialValue value="0">
                    <name>FEHBPolicy0</name>
                    <synopsis>
                    The FE will not generate any heartbeats to the CE.
                    </synopsis>



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                 </specialValue>
                 <specialValue value="1">
                    <name>FEHBPolicy1</name>
                    <synopsis>
                       The FE generates heartbeats to the CE every
                       FEHI if no other
                       messages have been sent to the CE.
                    </synopsis>
                 </specialValue>
              </specialValues>
           </atomic>
        </dataTypeDef>
        <dataTypeDef>
           <name>FERestartPolicyValues</name>
           <synopsis>
              The possible values of FE restart policy
           </synopsis>
           <atomic>
              <baseType>uchar</baseType>
              <specialValues>
                 <specialValue value="0">
                    <name>FERestartPolicy0</name>
                    <synopsis>
                       The FE restarts its state from scratch.
                    </synopsis>
                 </specialValue>
              </specialValues>
           </atomic>
        </dataTypeDef>
        <dataTypeDef>
           <name>HAModeValues</name>
           <synopsis>
              The possible values of HA modes
           </synopsis>
           <atomic>
              <baseType>uchar</baseType>
              <specialValues>
                 <specialValue value="0">
                    <name>NoHA</name>
                    <synopsis>
                       The FE is not running in HA mode.
                    </synopsis>
                 </specialValue>
                 <specialValue value="1">
                    <name>ColdStandby</name>
                    <synopsis>
                       The FE is running in HA mode cold standby.
                    </synopsis>



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                 </specialValue>
                 <specialValue value="2">
                    <name>HotStandby</name>
                    <synopsis>
                       The FE is running in HA mode hot standby.
                    </synopsis>
                 </specialValue>
              </specialValues>
           </atomic>
        </dataTypeDef>
        <dataTypeDef>
           <name>CEFailoverPolicyValues</name>
           <synopsis>
              The possible values of CE failover policy
           </synopsis>
           <atomic>
              <baseType>uchar</baseType>
              <specialValues>
                 <specialValue value="0">
                    <name>CEFailoverPolicy0</name>
                    <synopsis>
                        The FE should stop functioning immediately
                        and transition to FE OperDisable state.
                    </synopsis>
                 </specialValue>
                 <specialValue value="1">
                    <name>CEFailoverPolicy1</name>
                    <synopsis>
                        The FE should continue forwarding even
                        without an associated CE for CEFTI.  The
                        FE goes to FE OperDisable when the CEFTI
                        expires and there is no association.  Requires
                        graceful restart support.
                    </synopsis>
                 </specialValue>
              </specialValues>
           </atomic>
        </dataTypeDef>
        <dataTypeDef>
           <name>FEHACapab</name>
           <synopsis>
              The supported HA features
           </synopsis>
           <atomic>
              <baseType>uchar</baseType>
              <specialValues>
                 <specialValue value="0">
                    <name>GracefullRestart</name>



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                    <synopsis>
                       The FE supports graceful restart.
                    </synopsis>
                 </specialValue>
                 <specialValue value="1">
                    <name>HA</name>
                    <synopsis>
                       The FE supports HA.
                    </synopsis>
                 </specialValue>
              </specialValues>
           </atomic>
        </dataTypeDef>
        <dataTypeDef>
           <name>CEStatusType</name>
           <synopsis>Status values.  Status for each CE</synopsis>
           <atomic>
              <baseType>uchar</baseType>
              <specialValues>
                 <specialValue value="0">
                    <name>Disconnected</name>
                    <synopsis>No connection attempt with the CE yet
                    </synopsis>
                 </specialValue>
                 <specialValue value="1">
                    <name>Connected</name>
                    <synopsis>The FE connection with the CE at the TML
                       has been completed.
                    </synopsis>
                 </specialValue>
                 <specialValue value="2">
                    <name>Associated</name>
                    <synopsis>The FE has associated with the CE.
                    </synopsis>
                 </specialValue>
                 <specialValue value="3">
                    <name>IsMaster</name>
                    <synopsis>The CE is the master (and associated).
                    </synopsis>
                 </specialValue>
                 <specialValue value="4">
                    <name>LostConnection</name>
                    <synopsis>The FE was associated with the CE but
                       lost the connection.
                    </synopsis>
                 </specialValue>
                 <specialValue value="5">
                    <name>Unreachable</name>



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                    <synopsis>The CE is deemed as unreachable by the FE.
                    </synopsis>
                 </specialValue>
              </specialValues>
           </atomic>
        </dataTypeDef>
        <dataTypeDef>
           <name>StatisticsType</name>
           <synopsis>Statistics Definition</synopsis>
           <struct>
              <component componentID="1">
                 <name>RecvPackets</name>
                 <synopsis>Packets received</synopsis>
                 <typeRef>uint64</typeRef>
              </component>
              <component componentID="2">
                 <name>RecvErrPackets</name>
                 <synopsis>Packets received from CE with errors
                 </synopsis>
                 <typeRef>uint64</typeRef>
              </component>
              <component componentID="3">
                 <name>RecvBytes</name>
                 <synopsis>Bytes received from CE</synopsis>
                 <typeRef>uint64</typeRef>
              </component>
              <component componentID="4">
                 <name>RecvErrBytes</name>
                 <synopsis>Bytes received from CE in error</synopsis>
                 <typeRef>uint64</typeRef>
              </component>
              <component componentID="5">
                 <name>TxmitPackets</name>
                 <synopsis>Packets transmitted to CE</synopsis>
                 <typeRef>uint64</typeRef>
              </component>
              <component componentID="6">
                 <name>TxmitErrPackets</name>
                 <synopsis>
                    Packets transmitted to CE that incurred
                    errors
                 </synopsis>
                 <typeRef>uint64</typeRef>
              </component>
              <component componentID="7">
                 <name>TxmitBytes</name>
                 <synopsis>Bytes transmitted to CE</synopsis>
                 <typeRef>uint64</typeRef>



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              </component>
              <component componentID="8">
                 <name>TxmitErrBytes</name>
                 <synopsis>Bytes transmitted to CE incurring errors
                 </synopsis>
                 <typeRef>uint64</typeRef>
              </component>
           </struct>
        </dataTypeDef>
        <dataTypeDef>
           <name>AllCEType</name>
           <synopsis>Table Type for AllCE component</synopsis>
           <struct>
              <component componentID="1">
                 <name>CEID</name>
                 <synopsis>ID of the CE</synopsis>
                 <typeRef>uint32</typeRef>
              </component>
              <component componentID="2">
                 <name>Statistics</name>
                 <synopsis>Statistics per CE</synopsis>
                 <typeRef>StatisticsType</typeRef>
              </component>
              <component componentID="3">
                 <name>CEStatus</name>
                 <synopsis>Status of the CE</synopsis>
                 <typeRef>CEStatusType</typeRef>
              </component>
           </struct>
        </dataTypeDef>
        <dataTypeDef>
           <name>ExtendedResultType</name>
           <synopsis>
               Possible extended result support
           </synopsis>
           <atomic>
              <baseType>uchar</baseType>
              <rangeRestriction>
                <allowedRange min="1" max="2"/>
              </rangeRestriction>
              <specialValues>
                 <specialValue value="1">
                    <name>EResultNotSupported</name>
                    <synopsis>
                        Extended results are not supported.
                    </synopsis>
                 </specialValue>
                 <specialValue value="2">



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                    <name>EResultSupported</name>
                    <synopsis>
                        Extended results are supported.
                    </synopsis>
                 </specialValue>
              </specialValues>
           </atomic>
        </dataTypeDef>
     </dataTypeDefs>
     <LFBClassDefs>
        <LFBClassDef LFBClassID="2">
           <name>FEPO</name>
           <synopsis>
              The FE Protocol Object, with extended result control
           </synopsis>
           <version>1.2</version>
           <components>
              <component componentID="1" access="read-only">
                 <name>CurrentRunningVersion</name>
                 <synopsis>Currently running ForCES version</synopsis>
                 <typeRef>uchar</typeRef>
              </component>
              <component componentID="2" access="read-only">
                 <name>FEID</name>
                 <synopsis>Unicast FEID</synopsis>
                 <typeRef>uint32</typeRef>
              </component>
              <component componentID="3" access="read-write">
                 <name>MulticastFEIDs</name>
                 <synopsis>
                    The table of all multicast IDs
                 </synopsis>
                 <array type="variable-size">
                    <typeRef>uint32</typeRef>
                 </array>
              </component>
              <component componentID="4" access="read-write">
                 <name>CEHBPolicy</name>
                 <synopsis>
                    The CE Heartbeat Policy
                 </synopsis>
                 <typeRef>CEHBPolicyValues</typeRef>
              </component>
              <component componentID="5" access="read-write">
                 <name>CEHDI</name>
                 <synopsis>
                    The CE Heartbeat Dead Interval in milliseconds
                 </synopsis>



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                 <typeRef>uint32</typeRef>
              </component>
              <component componentID="6" access="read-write">
                 <name>FEHBPolicy</name>
                 <synopsis>
                    The FE Heartbeat Policy
                 </synopsis>
                 <typeRef>FEHBPolicyValues</typeRef>
              </component>
              <component componentID="7" access="read-write">
                 <name>FEHI</name>
                 <synopsis>
                    The FE Heartbeat Interval in milliseconds
                 </synopsis>
                 <typeRef>uint32</typeRef>
              </component>
              <component componentID="8" access="read-write">
                 <name>CEID</name>
                 <synopsis>
                    The Primary CE this FE is associated with
                 </synopsis>
                 <typeRef>uint32</typeRef>
              </component>
              <component componentID="9" access="read-write">
                 <name>BackupCEs</name>
                 <synopsis>
                    The table of all backup CEs other than the
                    primary
                 </synopsis>
                 <array type="variable-size">
                    <typeRef>uint32</typeRef>
                 </array>
              </component>
              <component componentID="10" access="read-write">
                 <name>CEFailoverPolicy</name>
                 <synopsis>
                    The CE Failover Policy
                 </synopsis>
                 <typeRef>CEFailoverPolicyValues</typeRef>
              </component>
              <component componentID="11" access="read-write">
                 <name>CEFTI</name>
                 <synopsis>
                    The CE Failover Timeout Interval in milliseconds
                 </synopsis>
                 <typeRef>uint32</typeRef>
              </component>
              <component componentID="12" access="read-write">



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                 <name>FERestartPolicy</name>
                 <synopsis>
                    The FE Restart Policy
                 </synopsis>
                 <typeRef>FERestartPolicyValues</typeRef>
              </component>
              <component componentID="13" access="read-write">
                 <name>LastCEID</name>
                 <synopsis>
                    The Primary CE this FE was last associated
                    with
                 </synopsis>
                 <typeRef>uint32</typeRef>
              </component>
              <component componentID="14" access="read-write">
                 <name>HAMode</name>
                 <synopsis>
                    The HA mode used
                 </synopsis>
                 <typeRef>HAModeValues</typeRef>
              </component>
              <component componentID="15" access="read-only">
                 <name>AllCEs</name>
                 <synopsis>The table of all CEs</synopsis>
                 <array type="variable-size">
                    <typeRef>AllCEType</typeRef>
                 </array>
               </component>
               <component componentID="16" access="read-write">
                 <name>EResultAdmin</name>
                 <synopsis>
                     Turn extended results off or on,
                     but default to off.
                 </synopsis>
                 <typeRef>ExtendedResultType</typeRef>
                 <defaultValue>1</defaultValue>
              </component>
           </components>
           <capabilities>
              <capability componentID="30">
                 <name>SupportableVersions</name>
                 <synopsis>
                    The table of ForCES versions that FE supports
                 </synopsis>
                 <array type="variable-size">
                    <typeRef>uchar</typeRef>
                 </array>
              </capability>



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              <capability componentID="31">
                 <name>HACapabilities</name>
                 <synopsis>
                    The table of HA capabilities the FE supports
                 </synopsis>
                 <array type="variable-size">
                    <typeRef>FEHACapab</typeRef>
                 </array>
              </capability>
               <capability componentID="32">
                 <name>EResultCapab</name>
                 <synopsis>
                    The table of supported result capabilities
                 </synopsis>
                 <array type="variable-size">
                    <typeRef>ExtendedResultType</typeRef>
                 </array>
             </capability>
           </capabilities>
           <events baseID="61">
              <event eventID="1">
                 <name>PrimaryCEDown</name>
                 <synopsis>
                    The primary CE has changed.
                 </synopsis>
                 <eventTarget>
                    <eventField>LastCEID</eventField>
                 </eventTarget>
                 <eventChanged/>
                 <eventReports>
                    <eventReport>
                       <eventField>LastCEID</eventField>
                    </eventReport>
                 </eventReports>
              </event>
              <event eventID="2">
                 <name>PrimaryCEChanged</name>
                 <synopsis>A new primary CE has been selected.
                 </synopsis>
                 <eventTarget>
                    <eventField>CEID</eventField>
                 </eventTarget>
                 <eventChanged/>
                 <eventReports>
                    <eventReport>
                       <eventField>CEID</eventField>
                    </eventReport>
                 </eventReports>



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              </event>
           </events>
        </LFBClassDef>
     </LFBClassDefs>
  </LFBLibrary>

Acknowledgments

   The author would like to thank Evangelos Haleplidis and Joel Halpern
   for discussions that made this document better.  Adrian Farrel did an
   excellent AD review of the document, which improved the quality of
   this document.  Tobias Gondrom did the Security Directorate review.
   Brian Carpenter did the Gen-ART review.  Nevil Brownlee performed the
   Operations Directorate review.  S. Moonesamy (SM) worked hard to
   review our publication process.  Pearl Liang caught issues in the
   IANA text.

   The author would like to thank the following IESG members who
   reviewed and improved this document: Alia Atlas, Barry Leiba, Brian
   Haberman, Kathleen Moriarty, Richard Barnes, and Spencer Dawkins.

Author's Address

   Jamal Hadi Salim
   Mojatatu Networks
   Suite 400, 303 Moodie Dr.
   Ottawa, Ontario  K2H 9R4
   Canada

   EMail: hadi@mojatatu.com





















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