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+Independent Submission S. Iino
+Request for Comments: 5414 S. Govindan
+Obsoleted by: 5415 M. Sugiura
+Category: Historic H. Cheng
+ISSN: 2070-1721 Panasonic
+ February 2010
+
+
+ Wireless LAN Control Protocol (WiCoP)
+
+Abstract
+
+ The popularity of wireless local area networks (WLANs) has led to
+ widespread deployments across different establishments. It has also
+ translated into an increasing scale of the WLANs. Large-scale
+ deployments made of large numbers of wireless termination points
+ (WTPs) and covering substantial areas are increasingly common.
+
+ The Wireless LAN Control Protocol (WiCoP) described in this document
+ allows for the control and provisioning of large-scale WLANs. It
+ enables central management of these networks and realizes the
+ objectives set forth for the Control And Provisioning of Wireless
+ Access Points (CAPWAP).
+
+Status of This Memo
+
+ This document is not an Internet Standards Track specification; it is
+ published for the historical record.
+
+ This document defines a Historic Document for the Internet community.
+ This is a contribution to the RFC Series, independently of any other
+ RFC stream. The RFC Editor has chosen to publish this document at
+ its discretion and makes no statement about its value for
+ implementation or deployment. Documents approved for publication by
+ the RFC Editor are not a candidate for any level of Internet
+ Standard; see 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/rfc5414.
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+Iino, et al. Historic [Page 1]
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+RFC 5414 WiCoP February 2010
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+
+IESG Note
+
+ This RFC documents the WiCoP protocol as it was when submitted to the
+ IETF as a basis for further work in the CAPWAP Working Group, and
+ therefore it may resemble the CAPWAP protocol specification in RFC
+ 5415, as well as other IETF work. This RFC is being published solely
+ for the historical record. The protocol described in this RFC has
+ not been thoroughly reviewed and may contain errors and omissions.
+
+ RFC 5415 documents the standards track solution for the CAPWAP
+ Working Group and obsoletes any and all mechanisms defined in this
+ RFC. This RFC itself is not a candidate for any level of Internet
+ Standard and should not be used as a basis for any sort of Internet
+ deployment.
+
+Copyright Notice
+
+ Copyright (c) 2010 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.
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+Iino, et al. Historic [Page 2]
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+RFC 5414 WiCoP February 2010
+
+
+Table of Contents
+
+ 1. Introduction ....................................................4
+ 2. Terminology .....................................................6
+ 3. Protocol Overview ...............................................6
+ 4. WiCoP Format ....................................................7
+ 4.1. WiCoP Header ...............................................8
+ 4.2. WiCoP Control Packet ......................................11
+ 4.2.1. WiCoP Control Messages .............................12
+ 4.2.2. WiCoP Control Message Elements .....................12
+ 4.2.3. WiCoP Control Message Description ..................27
+ 4.3. WiCoP Data Packet .........................................36
+ 4.4. WiCoP Timers ..............................................37
+ 4.4.1. Active Presence Timer ..............................37
+ 4.4.2. Feedback Interval ..................................37
+ 4.4.3. Response Timer .....................................37
+ 4.4.4. Wireless Connectivity Timer ........................38
+ 5. WiCoP Processes ................................................38
+ 5.1. Initialization ............................................38
+ 5.2. Capabilities Exchange .....................................38
+ 5.3. Connection ................................................39
+ 5.4. Configuration .............................................40
+ 5.4.1. Logical Groups .....................................41
+ 5.4.2. Resource Control ...................................41
+ 5.5. Operation .................................................41
+ 5.5.1. Updates ............................................42
+ 5.5.2. Feedback and Statistics ............................42
+ 5.5.3. Non-Periodic Events ................................43
+ 5.5.4. Firmware Trigger ...................................43
+ 5.5.5. Wireless Terminal Management .......................43
+ 5.5.6. Key Configuration ..................................46
+ 6. WiCoP Performance ..............................................51
+ 6.1. Operational Efficiency ....................................51
+ 6.2. Semantic Efficiency .......................................51
+ 7. Summary and Conclusion .........................................51
+ 8. Security Considerations ........................................52
+ 9. Informative References .........................................53
+
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+Iino, et al. Historic [Page 3]
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+RFC 5414 WiCoP February 2010
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+
+1. Introduction
+
+ The popularity of wireless local area networks (WLANs) has led to
+ numerous but incompatible designs and solutions. The CAPWAP
+ Architecture Taxonomy [RFC4118] describes major variations of these
+ designs. Among them, the Local MAC (Media Access Control) and Split
+ MAC architecture designs are notable categories.
+
+ Wireless LAN Control Protocol (WiCoP) recognizes the major
+ architecture designs and presents a common platform on which WLAN
+ entities of different designs can be accommodated. This enables
+ interoperability among wireless termination points (WTPs) and WLAN
+ access controllers (ACs) of distinct architecture designs. WiCoP
+ therefore allows for cost-effective WLAN expansions. It can also
+ accommodate future developments in WLAN technologies. Figure 1
+ illustrates the WiCoP operational structure in which distinct control
+ elements are utilized for Local MAC and Split MAC WTPs.
+
+ WiCoP also addresses the increasing trend of shared infrastructure
+ WLANs. Here, WLAN management needs to distinguish and isolate
+ control for the different logical groups sharing a single physical
+ WLAN. WiCoP manages WLANs through a series of tunnels that separate
+ traffic based on logical groups.
+
+ The WiCoP operational structure in Figure 1 shows that each WTP uses
+ a number of tunnels to distinguish and separate traffic for control
+ and for each logical group. The protocol allows for managing WLANs
+ in a manner consistent with the logical groups that share the
+ physical infrastructure.
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+ Local MAC WTP
+
+ +-------+ +-------+
+ | | | | Logical Groups
+ | (=====Control Tunnel======) |
+ | | | | ~~~~~~~
+ | | | | / /
+ | <=====Logical Group A=====> | / A /~~~~
+ | | | | / / /
+ | <=====Logical Group B=====> | ~~~~~~~ /~~~~
+ | | | | / B / /
+ | <=====Logical Group C=====> | ~~~~~~~ /
+ | | | | / C /
+ | | +-------+ ~~~~~~~
+ | |
+ | |
+ | AC |
+ | |
+ | | Split MAC WTP
+ | |
+ | | +-------+ Logical Groups
+ | | | |
+ | [=====Control Tunnel======] | ~~~~~~~
+ | | | | / /
+ | | | | / 1 /~~~~
+ | <=====Logical Group 1=====> | / / /
+ | | | | ~~~~~~~ /
+ | <=====Logical Group 2=====> | / 2 /
+ | | | | ~~~~~~~
+ +-------+ +-------+
+
+ Figure 1
+
+ In Figure 1, WiCoP establishes and operates control tunnels and
+ logical group tunnels between the AC and two types of WTPs. The
+ control tunnels are used to transport WiCoP messages dealing with the
+ configuration, monitoring, and management of WTPs as a physical
+ whole. The logical group tunnels serve to separate traffic among
+ each of the logical groups constituting a physical WTP.
+
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+Iino, et al. Historic [Page 5]
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+RFC 5414 WiCoP February 2010
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+
+2. Terminology
+
+ This document follows the terminologies of [RFC4118] and [RFC4564].
+
+3. Protocol Overview
+
+ The Wireless LAN Control Protocol (WiCoP) focuses on enabling
+ interoperability in shared infrastructure WLANs. It is designed for
+ use with different wireless technologies. This document provides
+ both the general operations of WiCoP and also specific use-cases with
+ respect to IEEE 802.11-based systems.
+
+ The state machine for WiCoP is illustrated in Figure 2.
+
+ +--------------------------------+
+ | |
+ | +------------------+ |
+ V V | |
+ +-------------+ +-------------+ +-------------+ |
+ | | | | | | |
+ | Initial- |-------->| Capabilities|-------->| Connection | |
+ | ization | | Exchange | | | |
+ | | | | | | |
+ +-------------+ +-------------+ +-------------+ |
+ A A | |
+ | | | |
+ | | | |
+ | | | |
+ | | V |
+ | | +-------------+ |
+ | | | | |
+ | +----------------| Configur- | |
+ | | ation | |
+ | | | |
+ | +-------------+ |
+ | | |
+ | | |
+ | | |
+ | | |
+ | V |
+ | +--------------+ |
+ | | | |
+ +----------------------------------------| |-+
+ | Operation |
+ | |
+ +--------------+
+ Figure 2
+
+
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+Iino, et al. Historic [Page 6]
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+RFC 5414 WiCoP February 2010
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+
+ The Initialization state represents the initial states of WTPs and
+ AC. A WTP or AC in this state powers on, clears internal registers,
+ runs hardware self-tests, and resets network interfaces.
+
+ The Capabilities Exchange state represents initial protocol exchange
+ between a WTP and AC. A WTP in this state determines possible ACs
+ from which it can receive management services. An AC in this state
+ determines the capabilities of the WTP and the WTP's compatibility
+ with the management services it offers.
+
+ The Connection state represents the creation of a security
+ infrastructure between a WTP and AC. This involves mutual
+ authentication and the establishment of a secure connection between
+ the WiCoP entities.
+
+ The Configuration state represents the exchange of long-term
+ operational parameters and settings between a WTP and AC. A WTP in
+ this state receives configuration information to allow it to operate
+ consistently within the WLAN managed by the AC. An AC in this state
+ provides configuration information to the WTP based on the WTP's
+ capabilities and network policies.
+
+ The Operation state represents the active exchange of WiCoP
+ monitoring and management messages. WTPs send regular status updates
+ to and receive corresponding management instructions from the AC.
+ This state also involves firmware and configuration updates arising
+ from changes in network conditions and administrative policies.
+
+4. WiCoP Format
+
+ WiCoP uses separate packets for control and data message transfer
+ between the AC and WTPs. A common header is used for both types of
+ packets in which a single-bit flag distinguishes between them. This
+ section presents the packet formats for WiCoP packets.
+
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+4.1. WiCoP Header
+
+ Figure 3 illustrates the WiCoP common header for control and data
+ packets.
+
+ 0 31
+ | 7 15 23 |
+ |-------|-------|-------|-------|-------|-------|-------|-------|
+ | |
+
+ +---------------+-+-+-+-+-+-+-+-+-------------------------------+
+ | Version |M|D|C|R|E|F|L| | Reserve |
+ +---------------+-+-+-+-+-+-+-+-+-------------------------------+
+ | Fragment ID | Fragment No. | Length |
+ +---------------+---------------+-------------------------------+
+
+ Figure 3
+
+ Version Field
+
+ This field indicates the protocol version.
+
+ 'M' Field
+
+ The MAC-type field, 'M', distinguishes between Local MAC WTPs and
+ Split MAC WTPs. It is used to efficiently realize interoperability
+ between WTPs of the two different designs. A '0' value indicates
+ WiCoP exchanges with a Split MAC WTP while a '1' value indicates
+ WiCoP exchanges with a Local MAC WTP.
+
+ The presence of this classification bit in the WiCoP common header
+ serves to expedite processing of WiCoP and WLAN traffic at the AC.
+ With a single parsing of the WiCoP common header once, the AC will be
+ able to determine the appropriate processing required for the
+ particular WiCoP packet.
+
+ 'D' Field
+
+ The differentiator field, 'D', is used to distinguish between WTP
+ variants within a type of WTP design. The CAPWAP Architecture
+ Taxonomy [RFC4118] illustrates that the Split MAC design allows
+ encryption/decryption to be performed at either the WTP or the AC.
+ The Architecture Taxonomy also indicates that the Local MAC design
+ allows authentication to take place at either the WTP or the AC.
+
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+ WiCoP acknowledges these major variants and accommodates them using
+ the 'D' field in conjunction with the 'M' field. For a Split MAC
+ WTP, the 'D' field is used to indicate location of
+ encryption/decryption while for a Local MAC WTP, the 'D' field is
+ used to indicate location of authentication. The following table
+ highlights their usage.
+
+ 'M' 'D' Description
+
+ 0 0 Split MAC WTP - Encryption/decryption
+ is performed at WTP
+ 0 1 Split MAC WTP - Encryption/decryption
+ is performed at AC
+ 1 0 Local MAC WTP - Authentication is
+ performed by WTP
+ 1 1 Local MAC WTP - Authentication is
+ performed by AC
+
+ Similar to the 'M' field, the presence of this classification in the
+ WiCoP common header helps expedite processing at the AC with a single
+ parsing. By incorporating the classification bits in the WiCoP
+ common header, where it is available for all packets of a session,
+ the AC processing can be expedited. Alternatively, the AC would have
+ to check each arriving packet against an internal register and
+ consequently delay processing.
+
+ 'C' Field
+
+ This field distinguishes between a WiCoP control and WiCoP data
+ packet. Each type of information is tunneled separately across the
+ WiCoP tunnel interfaces between WTPs and the AC. A '0' value for the
+ 'C' field indicates a data packet, while a '1' value indicates a
+ control packet.
+
+ The 'C' field is also used to assign WiCoP packets to distinct data
+ and control tunnels between the AC and WTP. WiCoP also maintains
+ logical groups in WLANs with the 'C' field.
+
+ 'R' Field
+
+ The retransmission field, 'R', is used to differentiate between the
+ first and subsequent transmissions of WiCoP packets. The 'R' field
+ is used for critical WiCoP packets such as those relating to security
+ key exchanges. A '0' value for the 'R' field indicates the first
+ transmission of a WiCoP packet, while a '1' value indicates a
+ retransmission.
+
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+ 'E' Field
+
+ The encryption field, 'E', is used to indicate if the WiCoP packet is
+ encrypted between the AC and WTPs. The 'E' field is used for those
+ WiCoP packets that are exchanged during initialization. A '0' value
+ indicates the WiCoP packet is unencrypted, while a '1' value
+ indicates the packet is encrypted.
+
+ 'F' Field
+
+ The fragmentation field indicates if the packet is a fragment of a
+ larger packet. A '0' value indicates a non-fragmented packet while a
+ '1' value indicates a fragmented packet. The 'F', 'L', 'Fragment
+ ID', and 'Fragment No.' fields are used together.
+
+ 'L' Field
+
+ This field is used to indicate the last fragment of a larger packet.
+ It is only valid when the 'F' field has a '1' value. A '0' value for
+ the 'L' field indicates the last fragment of a larger packet while a
+ '1' value indicates an intermediate fragment of a larger packet. The
+ 'F', 'L', 'Fragment ID', and 'Fragment No.' fields are used together.
+
+ Fragment ID Field
+
+ The Fragment ID identifies the larger packet that has been
+ fragmented. It is used to distinguish between fragments of different
+ large packets. This field is valid only when the 'F' field has a '1'
+ value. The 'F', 'L', 'Fragment ID', and 'Fragment No.' fields are
+ used together.
+
+ Fragment No. Field
+
+ The fragment number field identifies the sequence of fragments of a
+ larger packet. The value of the Fragment No. field is incremented
+ for each fragment of a larger packet so as to show the order of
+ fragments. This field is valid only when the 'F' field has a '1'
+ value. The 'F', 'L', 'Fragment ID', and 'Fragment No.' fields are
+ used together.
+
+ Length Field
+
+ This field specifies the length of the WiCoP payload following the
+ header.
+
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+4.2. WiCoP Control Packet
+
+ The WiCoP control header follows the WiCoP common header. It is
+ highlighted in Figure 5.
+
+ 0 31
+ | 7 15 23 |
+ |-------|-------|-------|-------|-------|-------|-------|-------|
+ | |
+
+ +---------------+---------------+-------------------------------+
+ | Msg Type | Reserve | Seq Num |
+ +---------------+---------------+-------------------------------+
+ | Msg Element Length |
+ +-------------------------------+
+
+ Figure 5
+
+ The control packet adds four additional fields to the common header.
+ These are described below:
+
+ Msg Type Field
+
+ The message type field specifies the type of control message
+ transported in the packet. The list of control messages is presented
+ in Section 5.2.1.
+
+ Seq Num Field
+
+ The sequence number field is used to map WiCoP request and response
+ sequences. The initiator of a WiCoP request message increments the
+ Seq Num field for each new request message. The responder then uses
+ these values of the Seq Num fields in its corresponding response
+ messages.
+
+ Msg Element Length Field
+
+ This field specifies the length in bytes of the subsequent WiCoP
+ control message element.
+
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+4.2.1. WiCoP Control Messages
+
+ The list of WiCoP control messages is shown below:
+
+ Message Msg Type
+ ------------------------------------------------------------
+
+ Capabilities 1
+ Capabilities Response 2
+ Connection 3
+ Connection Response 4
+ Configuration Request 5
+ Configuration Response 6
+ Configuration Data 7
+ Configuration Data Response 8
+ Configuration Trigger 9
+ Configuration Trigger Response 10
+ Feedback 11
+ Feedback Response 12
+ Reset 13
+ Reset Response 14
+ Firmware Download 15
+ Firmware Download Response 16
+ Terminal Addition 17
+ Terminal Addition Response 18
+ Terminal Deletion 19
+ Terminal Deletion Response 20
+ Key Configuration 21
+ Key Configuration Response 22
+ Notification 23
+ Notification Response 24
+
+4.2.2. WiCoP Control Message Elements
+
+ WiCoP control messages each include a control message header followed
+ by one or more message elements. The message elements are shown in
+ the following table:
+
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+ +-----------------+-----------+-------------------------------------+
+ | Message Element | Type | Description |
+ +-----------------+-----------+-------------------------------------+
+ | WTP-Info | 1 | Information regarding WTPs, such as |
+ | | | manufacturer ID, MAC address, etc. |
+ | | | |
+ | Cap-from-WTP | 2 | Quality-of-Service (QoS) abilities |
+ | | | (WME-Wireless Multimedia Extension) |
+ | | | and security abilities |
+ | | | (IEEE 802.11i) are included |
+ | | | |
+ | Conf-If-Data | 3 | Physical Layer (PHY) information for|
+ | | | each wireless interface |
+ | | | |
+ | Conf-WTP-Data | 4 | Information regarding logical |
+ | | | groups on a per-logical group basis |
+ | | | (e.g., per-virtual AP) |
+ | | | |
+ | Cap-to-WTP | 5 | Setup data sent to WTPs by an AC on |
+ | | | a per-logical group basis |
+ | | | |
+ | QoS-Value | 6 | QoS setup (access categories) |
+ | | | |
+ |Timer-Init-Value | 7 | Initial values of timers such as |
+ | | | aging, echo interval, etc. |
+ | | | |
+ | Terminal-Data | 8 | Information relevant to wireless |
+ | | | terminals - Basic Service Set |
+ | | | Identifier (BSSID), association ID, |
+ | | | etc. |
+ | | | |
+ | BSSID | 9 | BSSID, and terminal MAC address |
+ | | | |
+ | Encryption-Data | 10 | Details of the security framework - |
+ | | | cipher suit, operation mode, etc. |
+ | | | |
+ | EAP-Frame | 11 | Extensible Authentication Protocol |
+ | | | (EAP) frame |
+ | | | |
+ | Statistics | 12 | Various statistics information - |
+ | | | transmission attempts, Frame Check |
+ | | | Sequence (FCS) errors, etc. |
+ | | | |
+ | Interface-Error | 13 | Type of wireless interface failure |
+ | | | |
+ | FROM-Error | 14 | Flash ROM Error information |
+ | | | |
+ | QoS-Capability | 15 | Network congestion information |
+
+
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+ | | | |
+ | TFTP-Data | 16 | Firmware-related details |
+ | | | |
+ | Result | 17 | Result of protocol operations - |
+ | | | success or failure |
+ | | | |
+ | OID | 18 | Simple Network Management Protocol |
+ | | | (SNMP) Object Identifiers (OIDs) |
+ | | | |
+ | GTK-Flag | 19 | Determines type of Group Temporal |
+ | | | Key (GTK) - new or existing |
+ +-----------------+-----------+-------------------------------------+
+
+ Each message element comprises a number of information items that are
+ detailed below. The length of each information item is specified in
+ bytes.
+
+ WTP-Info:
+
+ Information included in the WTP-Info message element is provided on a
+ per-WTP basis, i.e., each WTP exchanges one WTP-Info message element.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | Manufacturer | 8 | DisplayString | Manufacturer ID |
+ | ID | | | |
+ | | | | |
+ | MAC Address | 6 | PhyAddress | WTP MAC Address |
+ | | | | |
+ | Firmware | 8 | DisplayString | Firmware version of |
+ | Version | | | WTP |
+ | | | | |
+ | Start Time | 4 | TimeTicks | Starting time of WTP |
+ | | | | (UNIX Time) |
+ +--------------+----------+----------------+------------------------+
+
+ Cap-from-WTP:
+
+ Information included in the Cap-from-WTP message element is provided
+ on a per-WTP basis, i.e., each WTP exchanges one Cap-from-WTP message
+ element.
+
+
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+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | 802.11e Cap | 2 | Integer | Length of 802.11e |
+ | Length | | | capabilities |
+ | | | | |
+ | 802.11e | Variable | OCTETString | 802.11e capabilities |
+ | Capabilities | | | of WTP. If WTP does |
+ | | | | not have such |
+ | | | | capabilities, this |
+ | | | | field is filled with |
+ | | | | '0' |
+ | | | | |
+ | 802.11i Cap | 2 | Integer | Length of 802.11i |
+ | Length | | | capabilities |
+ | | | | |
+ | 802.11i | Variable | OCTETString | 802.11i capabilities |
+ | Capabilities | | | of WTP. If WTP does |
+ | | | | not have such |
+ | | | | capabilities,this |
+ | | | | field is filled with |
+ | | | | '0' |
+ | | | | |
+ | AuthType | 2 | OCTETString | Type of authentication |
+ | | | | mechanism used between |
+ | | | | WTPs and the AC |
+ +--------------+----------+----------------+------------------------+
+
+ Conf-If-Data
+
+ The Conf-If-Data message element relates to the wireless interface.
+ A WTP with many interfaces will include corresponding numbers of
+ Conf-If-Data message elements within its control messages to the AC.
+ Conf-If-Data message elements are indexed by the If ID information
+ item.
+
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+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | If ID | 1 | Integer | Denotes identification |
+ | | | | of a wireless |
+ | | | | interface |
+ | | | | |
+ | Current | 1 | Integer | Current Power Level |
+ | Power | | | ('1' = Max; '2' = 1/2; |
+ | | | | '3' = 1/4; '4' = 1/8 |
+ | | | | |
+ | Radio | 1 | Integer | Radio channel of |
+ | Channel | | | operation |
+ | | | | |
+ | 2Dot4Mode | 1 | Integer | Interface mode in |
+ | | | | 2.4GHz. ('1' = IEEE |
+ | | | | 802.11b; '2' = IEEE |
+ | | | | 802.11g; '3' = Both) |
+ +--------------+----------+----------------+------------------------+
+
+ Conf-WTP-Data
+
+ Configuration information is provided on the basis of logical groups
+ such as virtual APs. There are multiple Conf-WTP-Data message
+ elements to address the many logical groups within a WLAN managed by
+ WiCoP. Conf-WTP-Data message elements are indexed by the BSSID
+ information item.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | BSSID | 6 | OCTETString | BSSID |
+ | | | | |
+ | ESSID | 32 | OCTETString | Extended Service Set |
+ | | | | Identifier (ESSID) |
+ | | | | |
+ | BSSID - | 32 | OCTETString | Mapping for logical |
+ | TunnelID | | | groups across BSSID |
+ | | | | and WiCoP tunnels |
+ | | | | |
+ | Beacon | 1 | Integer | Time interval between |
+ | Period | | | Beacon transmissions |
+ | | | | |
+ | DTIM Period | 1 | Integer | Delivery Traffic |
+ | | | | Indication Message |
+ | | | | (DTIM) period of |
+ | | | | Beacon transmissions |
+ | | | | |
+
+
+
+Iino, et al. Historic [Page 16]
+
+RFC 5414 WiCoP February 2010
+
+
+ | AnyRejectFla | 1 | Integer | Flag indicating WTP |
+ | g | | | rejection of any Probe |
+ | | | | Request within any |
+ | | | | SSID - ('1' = |
+ | | | | Rejected; '2' = Not |
+ | | | | Rejected) |
+ | | | | |
+ | SSID Stealth | 1 | Integer | Flag indicating |
+ | Flag | | | inclusion of ESSID |
+ | | | | within Beacon Frames |
+ | | | | ('1' = ESSID included; |
+ | | | | '2' = ESSID not |
+ | | | | included) |
+ | | | | |
+ | Operation | 2 | Integer | Data rates supported |
+ | Rate Set | | | by WTP for terminal |
+ | | | | being added using a |
+ | | | | 12-bit format for 1.1, |
+ | | | | 2.2, 3.55, 4.6, 5.9, |
+ | | | | 6.11, 7.12, 8.18, |
+ | | | | 9.24, 10.36, 11.48, |
+ | | | | and 12.54 Mbps |
+ | | | | |
+ | Encryption | 1 | Integer | Encryption Type - |
+ | Type | | | &#65288;'1' = OFF; '2' |
+ | | | | = WEP40; '3' = WEP104; |
+ | | | | '4' = WEP128) |
+ | | | | |
+ | Encryption | 16 | OCTETString | Static Encryption Key |
+ | Key | | | |
+ +--------------+----------+----------------+------------------------+
+
+ Cap-to-WTP:
+
+ Capabilities information is provided on the basis of logical groups
+ such as virtual APs. So, there are multiple Cap-to-WTP message
+ elements to address the many logical groups within a WLAN managed by
+ WiCoP. Conf-to-WTP message elements are indexed by the BSSID
+ information item. If logical groups are created by other means,
+ their corresponding identifier is used as the index.
+
+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 17]
+
+RFC 5414 WiCoP February 2010
+
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | BSSID | 6 | OCTETString | BSSID |
+ | | | | |
+ | 802.11e Cap | 2 | Integer | Length of 802.11e |
+ | Length | | | capabilities |
+ | | | | |
+ | 802.11e | Variable | OCTETString | 802.11e capabilities |
+ | Capabilities | | | of WTP. If WTP does |
+ | | | | not have such |
+ | | | | capabilities, this |
+ | | | | field is filled with |
+ | | | | '0' |
+ | | | | |
+ | 802.11i Cap | 2 | Integer | Length of 802.11i |
+ | Length | | | capabilities |
+ | | | | |
+ | 802.11i | Variable | OCTETString | 802.11i capabilities |
+ | Capabilities | | | of WTP. If WTP does |
+ | | | | not have such |
+ | | | | capabilities, this |
+ | | | | field is filled with |
+ | | | | '0' |
+ +--------------+----------+----------------+------------------------+
+
+ QoS-Value:
+
+ QoS parameters are assigned for each logical group to address their
+ respective individual conditions and requirements. QoS-Value message
+ elements are provided on a per-logical group basis. They are indexed
+ by the BSSID information item. If logical groups are created by
+ other means, their corresponding identifier is used as the index.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 18]
+
+RFC 5414 WiCoP February 2010
+
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | BSSID | 6 | OCTETString | BSSID |
+ | | | | |
+ | WTP AC_BE | 2 | Integer | AC Parameters Record |
+ | | | | AC_BE in WTP |
+ | | | | |
+ | WTP AC_BK | 2 | Integer | AC Parameters Record |
+ | | | | AC_BK in WTP |
+ | | | | |
+ | WTP AC_VI | 2 | Integer | AC Parameters Record |
+ | | | | AC_VI in WTP |
+ | | | | |
+ | WTP AC_VO | 2 | Integer | AC Parameters Record |
+ | | | | AC_VO in WTP |
+ | | | | |
+ | TE AC_BE | 2 | Integer | AC Parameters Record |
+ | | | | AC_BE in terminals |
+ | | | | |
+ | TE AC_BK | 2 | Integer | AC Parameters Record |
+ | | | | AC_BK in terminals |
+ | | | | |
+ | TE AC_VI | 2 | Integer | AC Parameters Record |
+ | | | | AC_VI in terminals |
+ | | | | |
+ | TE AC_VO | 2 | Integer | AC Parameters Record |
+ | | | | AC_VO in terminals |
+ +--------------+----------+----------------+------------------------+
+
+ Timer-Init-Value:
+
+ WiCoP timers are used for the WTP as a whole. So, the Timer-Init-
+ Value message element is provided on a per-WTP basis.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 19]
+
+RFC 5414 WiCoP February 2010
+
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | BSSID | 6 | OCTETString | BSSID |
+ | | | | |
+ | Response | 4 | Integer | Initial value of |
+ | Timer | | | Response Timer |
+ | | | | |
+ | Active | 4 | Integer | Initial value of |
+ | Presence | | | Active Presence Timer |
+ | Timer | | | |
+ | | | | |
+ | Feedback | 4 | Integer | Initial value of |
+ | Interval | | | Feedback Interval |
+ | Timer | | | Timer |
+ +--------------+----------+----------------+------------------------+
+
+ Terminal-Data:
+
+ The Terminal-Data message element is applicable for both Local MAC
+ and Split MAC WTP designs. In the case of Local MAC, Terminal-Data
+ is sent from WTPs to the AC. In the case of Split MAC, Terminal-Data
+ is sent from the AC to WTPs. So, the direction of usage depends on
+ the type of WTP at which wireless terminal operations are performed.
+ Some information items may be optional for use with specific WTP
+ designs.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 20]
+
+RFC 5414 WiCoP February 2010
+
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | BSSID | 6 | PhyAddress | BSSID in which |
+ | | | | terminal is being |
+ | | | | added |
+ | | | | |
+ | MAC Address | 6 | PhyAddress | MAC address of |
+ | | | | terminal being added |
+ | | | | |
+ | Association | 2 | Integer | Association ID of |
+ | ID | | | terminal being added |
+ | | | | |
+ | Operation | 2 | Integer | Data rates supported |
+ | Rate Set | | | by WTP for terminal |
+ | | | | being added using a |
+ | | | | 12-bit format for 1.1, |
+ | | | | 2.2, 3.55, 4.6, 5.9, |
+ | | | | 6.11, 7.12, 8.18, |
+ | | | | 9.24, 10.36, 11.48, |
+ | | | | and 12.54 Mbps |
+ | | | | |
+ | Listen | 2 | Integer | Listen period |
+ | Period | | | |
+ +--------------+----------+----------------+------------------------+
+
+ BSSID:
+
+ The BSSID message element is used to identify logical groups within a
+ WLAN. WiCoP may be extended for other types of logical groups by
+ simply including additional message elements.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | BSSID | 6 | PhyAddress | BSSID in which |
+ | | | | terminal is being |
+ | | | | added |
+ | | | | |
+ | MAC Address | 6 | PhyAddress | MAC address of |
+ | | | | terminal being added |
+ +--------------+----------+----------------+------------------------+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 21]
+
+RFC 5414 WiCoP February 2010
+
+
+ Encryption-Data:
+
+ The Encryption-Data message element contains information relevant for
+ configuring security keys at WTPs. It is used in architectures in
+ which the authentication and encryption points are located in
+ distinct WLAN entities.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | MAC Address | 6 | PhyAddress | MAC address of |
+ | | | | terminal |
+ | | | | |
+ | Operation | 1 | Integer | Operational Mode ('1' |
+ | | | | = Set Key; '2' = |
+ | | | | Delete Key) |
+ | | | | |
+ | Key Index | 1 | Integer | Key Index - valid when |
+ | | | | Operational Mode = Set |
+ | | | | Key |
+ | | | | |
+ | Key Flag | 1 | Integer | Key Flag ('1' = |
+ | | | | Unicast Key or PTK; |
+ | | | | '2' = Broadcast Key or |
+ | | | | GTK) - valid only when |
+ | | | | Operational Mode = Set |
+ | | | | Key |
+ | | | | |
+ | Cipher Suit | 1 | Integer | Encryption Type ('1' = |
+ | | | | WEP40; '2' = WEP104; |
+ | | | | '3' = WEP128; '4' = |
+ | | | | TKIP; '5' = AES) - |
+ | | | | valid only when |
+ | | | | Operational Mode = Set |
+ | | | | Key |
+ | | | | |
+ | Key | 32 | OCTETString | Key body - valid only |
+ | | | | when Operational Mode |
+ | | | | = Set Key |
+ +--------------+----------+----------------+------------------------+
+
+ EAP-Frame:
+
+ The EAP-Frame message element is used to carry EAP frames used in the
+ configuration and management of the WLAN.
+
+
+
+
+
+
+Iino, et al. Historic [Page 22]
+
+RFC 5414 WiCoP February 2010
+
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | MAC Address | 6 | PhyAddress | MAC address of |
+ | | | | terminal |
+ | | | | |
+ | EAP | Variable | OCTETString | EAP Frames |
+ +--------------+----------+----------------+------------------------+
+
+ Statistics:
+
+ Statistics information covers all aspects of WTPs. As such, this
+ message element is provided on a per-WTP basis. WiCoP messages
+ containing the Statistics message element simultaneously serve as
+ keepalive signals between WTPs and the AC.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | OutOctet | 4 | Counter 32 | Octet number of frame |
+ | | | | WTP transmits |
+ | | | | |
+ | Transmit | 4 | Counter 32 | Total number of frames |
+ | Count | | | transmitted by WTP |
+ | | | | |
+ | Successful | 4 | Counter 32 | Total number of ACKs |
+ | Transmit | | | received |
+ | Count | | | |
+ | | | | |
+ | ACK Failure | 4 | Counter 32 | Total number of failed |
+ | Count | | | ACKs |
+ | | | | |
+ | InOctets | 4 | Counter 32 | Octet number of frame |
+ | | | | WTP receives |
+ | | | | |
+ | Receive | 4 | Counter 32 | Total number of frames |
+ | Count | | | received by WTP |
+ | | | | |
+ | Receive | 4 | Counter 32 | Total number of |
+ | Discard | | | received frames that |
+ | | | | are discarded |
+ | | | | |
+ | Retransmissi | 4 | Counter 32 | Number of WTP |
+ | on Count | | | retransmission |
+ | | | | attempts" |
+ | | | | |
+
+
+
+
+
+Iino, et al. Historic [Page 23]
+
+RFC 5414 WiCoP February 2010
+
+
+ | Duplicate | 4 | Counter 32 | Number of duplicate |
+ | Receive | | | frames received by WTP |
+ | Count | | | |
+ | | | | |
+ | FCS Error | 4 | Counter32 | Number of frames |
+ | Receive | | | received with FCS |
+ | Count | | | errors |
+ | | | | |
+ | Unknown | 4 | Counter 32 | Number of unknown |
+ | Frame | | | protocol frames |
+ | Receive | | | received |
+ | Count | | | |
+ | | | | |
+ | Beacon | 4 | Counter 32 | Number of transmitted |
+ | Transmit | | | Beacon frames |
+ | Count | | | |
+ | | | | |
+ | Probe | 4 | Counter 32 | Number of transmitted |
+ | Transmit | | | Probe Response frames |
+ | Count | | | |
+ | | | | |
+ | Probe | 4 | Counter 32 | Number of received |
+ | Receive | | | Probe Response frames |
+ | Count | | | |
+ | | | | |
+ | Decrypt CRC | 4 | Counter 32 | Number of received |
+ | Error Count | | | frames that cannot |
+ | | | | decrypt |
+ +--------------+----------+----------------+------------------------+
+
+ Interface-Error:
+
+ This message element is used to exchange information on error
+ conditions related to the wireless interface.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | Interface | 1 | Integer | Interface ID |
+ | Index | | | |
+ | | | | |
+ | Error Type | 1 | Integer | Type of error ('1' = |
+ | | | | Unrecoverable; '2' = |
+ | | | | Recoverable) |
+ +--------------+----------+----------------+------------------------+
+
+
+
+
+
+
+Iino, et al. Historic [Page 24]
+
+RFC 5414 WiCoP February 2010
+
+
+ FROM-Error:
+
+ The FROM-Error message element is used to exchange information on
+ error conditions related to flash ROMs in WTPs or the AC.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | FROM Index | 1 | Integer | FROM ID |
+ | | | | |
+ | Error Type | 1 | Integer | Type of error ('1' = |
+ | | | | Unrecoverable; '2' = |
+ | | | | Recoverable) |
+ +--------------+----------+----------------+------------------------+
+
+ QoS Capability:
+
+ The QoS-Capability message element is used to exchange information
+ concerning the Enhanced Distributed Channel Access (EDCA) and HCF
+ Controlled Channel Access (HCCA) capabilities of WTPs.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | EDCA | 1 | Integer | EDCA Capability ('1' = |
+ | | | | Capable; '2' = Not |
+ | | | | capable) |
+ | | | | |
+ | HCCA | 1 | Integer | HCCA Capability ('1' = |
+ | | | | Capable; '2' = Not |
+ | | | | capable) |
+ +--------------+----------+----------------+------------------------+
+
+ TFTP-Data:
+
+ This message element is for firmware data from an AC to WTPs.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | TFTP Data | Variable | OCTETString | Details of Trivial File|
+ | | | | Transfer Protocol |
+ | | | | (TFTP) |
+ +--------------+----------+----------------+------------------------+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 25]
+
+RFC 5414 WiCoP February 2010
+
+
+ Result:
+
+ The Result message element is used in all WiCoP response messages to
+ indicate the status of WiCoP request messages.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | Result Code | 1 | Integer | '1' = OK; '2' = NG |
+ +--------------+----------+----------------+------------------------+
+
+ OID:
+
+ The OID message element is used for general configuration information
+ specified by OIDs.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | Length | 1 | Integer | Length of OID String |
+ | | | | and OID Value |
+ | | | | |
+ | OID String | Variable | OCTETString | Object Identifier that |
+ | | | | is assigned according |
+ | | | | to Basic Encoding |
+ | | | | Rules (BER) |
+ | | | | |
+ | Value | Variable | OCTETString | Value |
+ +--------------+----------+----------------+------------------------+
+
+ GTK-Flag:
+
+ The GTK-Flag message element is used to inform the WTP on the type of
+ GTK used and correspondingly how the KeyMIC is to be computed.
+
+ +--------------+----------+----------------+------------------------+
+ | Item | Length | Syntax | Description |
+ +--------------+----------+----------------+------------------------+
+ | GTK Flag | 1 | Integer | Determines the type of |
+ | | | | GTK ('1' = New; '2' = |
+ | | | | Existing) |
+ +--------------+----------+----------------+------------------------+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 26]
+
+RFC 5414 WiCoP February 2010
+
+
+4.2.3. WiCoP Control Message Description
+
+ Message: Capabilities
+ Direction: WTP -> AC
+ Type: Request
+
+ Description: WTPs send a Capabilities message upon transitioning from
+ the Initialization state to the Capabilities Exchange state. The
+ message serves to discover and identify the controlling AC of the
+ WLAN and to provide it with identification and capabilities
+ information. In the IEEE 802.11 use-case, the Capabilities message
+ also specifies the WTP's IEEE 802.11e and IEEE 802.11i features.
+
+ TLV: The Capabilities message includes message elements of types 1
+ and 2.
+
+ +----------------+
+ | Capabilities |
+ +----------------+
+ | WTP-Info |
+ | |
+ | Cap-from-WTP |
+ +----------------+
+
+ Message: Capabilities Response
+ Direction: AC -> WTP
+ Type: Response
+
+ Description: This message is sent by an AC after examining the
+ compatibility of the WTP and its capabilities. The compatibility is
+ with respect to the MAC architecture that can be supported by the AC.
+ If the WTP is determined to be compatible, the Capabilities Response
+ message also contains information on the capabilities of the AC.
+
+ TLV: The Capabilities Response message includes message elements of
+ types 5 and 17. The Cap-to-WTP message elements are distinguished
+ based on BSSIDs to represent different logical groups.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 27]
+
+RFC 5414 WiCoP February 2010
+
+
+ +-----------------------+
+ | Capabilities Response |
+ +-----------------------+
+ | Cap-to-WTP 1 |
+ | |
+ | Cap-to-WTP ... |
+ | |
+ | Cap-to-WTP n |
+ | |
+ | Result |
+ +-----------------------+
+
+ Message: Connection
+ Direction: WTP -> AC
+ Type: Request
+
+ Description: The Connection message initiates the mutual security
+ association between an AC and WTPs. This message carries the first
+ message of the chosen security protocol. The specific security
+ mechanism for the authentication is out of scope of the WiCoP
+ specifications.
+
+ TLV: The Connection message includes message elements of type 2.
+
+ +---------------+
+ | Connection |
+ +---------------+
+ | Cap-from-WTP |
+ +---------------+
+
+ Message: Connection Response
+ Direction: AC -> WTP
+ Type: Response
+
+ Description: After completion of the security protocol exchange, this
+ message indicates the result of the WTP-AC security association. If
+ successful, it also represents the admission of the WTP into the
+ WLAN.
+
+ TLV: Type 17 message element is included.
+
+ +---------------------+
+ | Connection Response |
+ +---------------------+
+ | Result |
+ +---------------------+
+
+
+
+
+
+Iino, et al. Historic [Page 28]
+
+RFC 5414 WiCoP February 2010
+
+
+ Message: Configuration Request
+ Direction: WTP -> AC
+ Type: Request
+
+ Description: This message starts the Configuration state for the WTP.
+ It is a request for configuration information from the WTPs to the
+ AC.
+
+ Message: Configuration Response
+ Direction: AC -> WTP
+ Type: Response
+
+ Description: This is an acknowledgement for the Configuration Request
+ message.
+
+ TLV: Type 17 message element is included.
+
+ +------------------------+
+ | Configuration Response |
+ +------------------------+
+ | Result |
+ +------------------------+
+
+ Message: Configuration Data
+ Direction: AC -> WTP
+ Type: Request
+
+ Description: Configuration information including operational
+ parameters, QoS settings, and timer values is sent using the
+ Configuration Data message. This message is also used for
+ configuration updates in the Operation state of WiCoP.
+
+ TLV: This message includes message elements of types 3, 4, 5, 6, and
+ 7. The Conf-WTP-Data and QoS-Value message elements are identified
+ by BSSIDs to denote logical groups, while the Conf-If-Data message
+ elements are identified by If-IDs to denote multiple wireless radios.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 29]
+
+RFC 5414 WiCoP February 2010
+
+
+ +---------------------+
+ | Configuration Data |
+ +---------------------+
+ | Conf-If-Data 1 |
+ | |
+ | Conf-If-Data ... |
+ | |
+ | Conf-If-Data n |
+ | |
+ | Conf-WTP-Data 1 |
+ | |
+ | Conf-WTP-Data ... |
+ | |
+ | Conf-WTP-Data n |
+ | |
+ | Cap-to-WTP 1 |
+ | |
+ | Cap-to-WTP ... |
+ | |
+ | Cap-to-WTP n |
+ | |
+ | QoS-Value 1 |
+ | |
+ | QoS-Value ... |
+ | |
+ | QoS-Value n |
+ | |
+ | Timer-Init-Value |
+ +---------------------+
+
+ Message: Configuration Data Response
+ Direction: WTP -> AC
+ Type: Response
+
+ Description: This is an acknowledgement for the Configuration Data
+ message.
+
+ TLV: Type 17 message element is included.
+
+ +-----------------------------+
+ | Configuration Data Response |
+ +-----------------------------+
+ | Result |
+ +-----------------------------+
+
+ Message: Configuration Trigger
+ Direction: AC -> WTP
+ Type: Request
+
+
+
+Iino, et al. Historic [Page 30]
+
+RFC 5414 WiCoP February 2010
+
+
+ Description: This message is used to trigger the activation of the
+ configuration information sent in earlier Configuration messages.
+
+ Message: Configuration Trigger Response
+ Direction: WTP -> AC
+ Type: Response
+
+ Description: This is an acknowledgement of the Configuration Trigger.
+ This response message is sent before activation of the configuration
+ information.
+
+ TLV: Message elements of type 17 are included.
+
+ +--------------------------------+
+ | Configuration Trigger Response |
+ +--------------------------------+
+ | Result |
+ +--------------------------------+
+
+ Message: Reset
+ Direction: AC -> WTP
+ Type: Request
+
+ Description: This message from the AC instructs the WTP to clear
+ registers and revert to initial conditions.
+
+ Message: Reset Response
+ Direction: WTP -> AC
+ Type: Response
+
+ Description: This is an acknowledgement for the Reset message to the
+ AC.
+
+ TLV: Message elements of type 17 are included.
+
+ +----------------+
+ | Reset Response |
+ +----------------+
+ | Result |
+ +----------------+
+
+ Message: Feedback
+ Direction: WTP <-> AC
+ Type: Request
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 31]
+
+RFC 5414 WiCoP February 2010
+
+
+ Description:
+ WTP: The Feedback message is used to send regular statistics
+ information to the AC. It also serves as a keepalive
+ indicator used to update the Active Presence Timer
+ maintained by the AC.
+ AC: The Feedback message is used to determine the active state
+ of WTPs.
+
+ TLV: This message includes message elements of type 12.
+
+ +-------------+
+ | Feedback |
+ +-------------+
+ | Statistics |
+ +-------------+
+
+ Message: Feedback Response
+ Direction: WTP <-> AC
+ Type: Response
+
+ Description: This is an acknowledgement for Feedback messages.
+
+ TLV: Message elements of type 17 are included.
+
+ +-------------------+
+ | Feedback Response |
+ +-------------------+
+ | Result |
+ +-------------------+
+
+ Message: Firmware Download
+ Direction: AC -> WTP
+ Type: Request
+
+ Description: This message is used to instruct WTPs to update their
+ firmware. The message element contains information regarding the new
+ firmware.
+
+ TLV: Message elements of type 16 are included.
+
+ +-------------------+
+ | Firmware Download |
+ +-------------------+
+ | TFTP-Data |
+ +-------------------+
+
+
+
+
+
+
+Iino, et al. Historic [Page 32]
+
+RFC 5414 WiCoP February 2010
+
+
+ Message: Firmware Download Response
+ Direction: WTP -> AC
+ Type: Request Response
+
+ Description: This is an acknowledgement for the Firmware Download
+ message.
+
+ TLV: Message elements of type 17 are included.
+
+ +----------------------------+
+ | Firmware Download Response |
+ +----------------------------+
+ | Result |
+ +----------------------------+
+
+ Message: Notification
+ Direction: WTP <-> AC
+ Type: Request
+
+ Description: This message is used to indicate non-periodic events.
+ It may be sent by either WTPs or the AC. Notification messages
+ indicate failures, non-periodic changes, etc.
+
+ TLV: Message elements of types 13 and 14 are included.
+
+ +------------------+
+ | Notification |
+ +------------------+
+ | Interface-Error |
+ | |
+ | FROM-Error |
+ +------------------+
+
+ Message: Notification Response
+ Direction: WTP <-> AC
+ Type: Response
+
+ Description: This is an acknowledgement for the Notification message.
+ It may be followed by Configuration messages to rectify errors.
+
+ TLV: Message elements of type 17 are included.
+
+ +-----------------------+
+ | Notification Response |
+ +-----------------------+
+ | Result |
+ +-----------------------+
+
+
+
+
+Iino, et al. Historic [Page 33]
+
+RFC 5414 WiCoP February 2010
+
+
+ Message: Terminal Addition
+ Direction: WTP <-> AC
+ Type: Request
+
+ Description: This message may be sent from WTPs or the AC, depending
+ on the WTP type in consideration. In both cases, it is sent in
+ response to an IEEE 802.11 association frame.
+
+ For Split MAC WTPs, Terminal Addition is sent from the AC to the WTPs
+ and includes information on the wireless terminal relevant to the
+ WTP.
+
+ For Local MAC WTPs, Terminal Addition is sent from a WTP to the AC
+ and contains information on the wireless terminal relevant to the AC.
+
+ TLV: Message elements of type 8 are included.
+
+ +-------------------+
+ | Terminal Addition |
+ +-------------------+
+ | Terminal-Data |
+ +-------------------+
+
+ Message: Terminal Addition Response
+ Direction: WTP <-> AC
+ Type: Response
+
+ Description: This is an acknowledgement sent from either WTPs or the
+ AC, depending on the WTP type in consideration.
+
+ TLV: Message elements of type 17 are included.
+
+ +----------------------------+
+ | Terminal Addition Response |
+ +----------------------------+
+ | Result |
+ +----------------------------+
+
+ Message: Terminal Deletion
+ Direction: WTP <-> AC
+ Type: Request
+
+ Description: This message is sent in response to a disconnection of a
+ wireless terminal. It can be sent from WTPs or the AC. In both
+ cases, Terminal Deletion instructs the recipient to remove any state
+ information relating to the specific wireless terminal. The message
+
+
+
+
+
+Iino, et al. Historic [Page 34]
+
+RFC 5414 WiCoP February 2010
+
+
+ is sent in response to an IEEE 802.11 disassociation frame, IEEE
+ 802.11 deauthentication frame, or due to the expiration of the Active
+ Presence Timer.
+
+ For Split MAC WTPs, Terminal Deletion is sent from the AC to the
+ WTPs.
+
+ For Local MAC WTPs, Terminal Deletion is sent from the WTPs to the
+ AC.
+
+ TLV: Message elements of type 9 are included.
+
+ +-------------------+
+ | Terminal Deletion |
+ +-------------------+
+ | BSSID |
+ +-------------------+
+
+ Message: Terminal Deletion Response
+ Direction: WTP <-> AC
+ Type: Response
+
+ Description: This is an acknowledgement sent from either WTPs or the
+ AC, depending on the WiCoP interface.
+
+ TLV: Message elements of type 17 are included.
+
+ +----------------------------+
+ | Terminal Addition Response |
+ +----------------------------+
+ | Result |
+ +----------------------------+
+
+ Message: Key Configuration
+ Direction: AC -> WTP
+ Type: Request
+
+ Description: This message is used when authentication and encryption
+ points are located in distinct WLAN entities. WiCoP uses it in cases
+ where 'M' = 0 and 'D' = 0 or where 'M' = 1 and 'D' = 1. It is used
+ to configure security key information from the AC to the WTPs.
+
+ TLV: The following message elements are included for Key
+ Configuration.
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 35]
+
+RFC 5414 WiCoP February 2010
+
+
+ +-------------------+
+ | Key Configuration |
+ +-------------------+
+ | GTK-Flag |
+ | |
+ | Encryption-Data |
+ | |
+ | EAP-Frame |
+ +-------------------+
+
+ Message: Key Configuration Response
+ Direction: WTP -> AC
+ Type: Response
+
+ Description: This is an acknowledgement for the Key Configuration
+ message.
+
+ TLV: Message elements of type 17 are included.
+
+ +----------------------------+
+ | Key Configuration Response |
+ +----------------------------+
+ | Result |
+ +----------------------------+
+
+4.3. WiCoP Data Packet
+
+ WiCoP data packets include the WiCoP common header followed by a
+ payload. Data packets are used to distinguish traffic from control
+ when both control and data paths are identical. Such a scenario
+ would involve data traffic of the WTPs traversing the AC. However,
+ given the diversity of large-scale WLAN deployments, there are
+ scenarios in which data and control paths are distinct. WiCoP can be
+ used in both cases.
+
+ The WiCoP data packet format is illustrated below in Figure 7,
+ together with the WiCoP common header.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 36]
+
+RFC 5414 WiCoP February 2010
+
+
+ 0 31
+ | 7 15 23 |
+ |-------|-------|-------|-------|-------|-------|-------|-------|
+ | |
+
+ +---------------+-+-+-+-+-+-+-+-+-------------------------------+
+ | Version |M|D|C|R|E|F|L| | Reserve |
+ +---------------+-+-+-+-+-+-+-+-+-------------------------------+
+ | Fragment ID | Fragment No. | Length |
+ +---------------+---------------+-------------------------------+
+ | Payload |
+ +---------------------------------------------------------------+
+
+ Figure 7
+
+4.4. WiCoP Timers
+
+ WiCoP uses a number of timers to determine WLAN status and maintain
+ system performance. Timers are maintained by all WiCoP entities.
+
+4.4.1. Active Presence Timer
+
+ The Active Presence Timer is used by each WiCoP entity -- AC and WTPs
+ -- to verify the presence of each other. The absence of a reply to
+ the Feedback message within the expiration of the Active Presence
+ Timer indicates the corresponding entity is inactive. Contingency
+ operations such as reset are used in this case. The value of the
+ Active Presence Timer ranges from 10 to 300 seconds with a default
+ value of 30 seconds.
+
+4.4.2. Feedback Interval
+
+ Feedback messages are periodic with the frequency defined by the
+ Feedback Interval. The interval is set during WTP configuration. It
+ has a value ranging from 1 to 100 seconds and a default value of 10
+ seconds.
+
+ The Feedback Interval timer sets the periodicity of WLAN system
+ audits. So with this timer, the WLAN controller receives regular
+ information on the state of the WLAN and all its WTPs.
+
+4.4.3. Response Timer
+
+ This is a general-purpose timer used to limit the elapsed time
+ between transmission of a request message and receipt of a
+ corresponding response message. The value of this timer ranges from
+ 1 to 3 seconds with a default value of 1 second.
+
+
+
+
+Iino, et al. Historic [Page 37]
+
+RFC 5414 WiCoP February 2010
+
+
+4.4.4. Wireless Connectivity Timer
+
+ This timer triggers any changes in wireless connectivity. WiCoP uses
+ this timer to send Notification and other messages relating to
+ wireless conditions. It is also used to trigger the disconnection of
+ mobile terminals without disassociation. The value of the Wireless
+ Connectivity Timer ranges from 1 minute to 86,400 minutes with a
+ default value of 10 minutes.
+
+5. WiCoP Processes
+
+ The processes of the Wireless LAN Control Protocol are described in
+ this section with respect to the operational state in which they
+ occur.
+
+5.1. Initialization
+
+ The Initialization state represents the initial conditions of WiCoP
+ entities. WTPs and ACs in this state are powered on, run hardware
+ self-check tests, and reset network interfaces.
+
+ State transition: Initialization -> Capabilities Exchange
+ WTP: Automatically upon detecting an active network interface
+ AC: Upon receiving a Capabilities message from a WTP
+
+5.2. Capabilities Exchange
+
+ The Capabilities Exchange state allows WTPs to first find an AC and
+ then to exchange capabilities information with it.
+
+ WiCoP is designed to control WLANs with both Local MAC and Split MAC
+ WTPs. The differences in their respective functional characteristics
+ are determined in this state.
+
+ The WTP first broadcasts a Capabilities message as soon as it
+ transitions from its Initialization state. The Capabilities message
+ serves to discover ACs and contains information on its identity and
+ capabilities.
+
+ The AC receiving the Capabilities message transitions from its
+ Initialization state. It examines compatibility with respect to the
+ WTP type, its capabilities, and responds with an appropriate
+ Capabilities Response message.
+
+ The WTP continues to send Capabilities messages at an interval
+ specified by the Response Timer until it receives a Capabilities
+ Response message from an AC.
+
+
+
+
+Iino, et al. Historic [Page 38]
+
+RFC 5414 WiCoP February 2010
+
+
+ The AC maintains a count of Capabilities messages received from a
+ given WTP, which it uses to ignore WTPs after a limit. This is to
+ ensure that rogue WTPs that are not compatible with the AC do not
+ repeatedly attempt connections. The limit of connection attempts is
+ 3 within 60 seconds.
+
+ State transition: Capabilities Exchange -> Connection
+ WTP: Upon receiving a positive Capabilities Response message
+ from an AC
+ AC: Upon receiving a Connection Request message from a WTP
+
+5.3. Connection
+
+ The Connection state involves establishing a security infrastructure
+ between WTPs and an AC.
+
+ The WTP sends a Connection message to trigger the authentication and
+ security mechanism, i.e., this message initiates an IPsec security
+ association.
+
+ The AC sends a positive Connection Response message after
+ establishment of the security association or a negative Connection
+ Response message if an error occurs. The AC also monitors the
+ receipt of WiCoP control messages to prevent replay attacks.
+
+ The security association between an AC and WTPs covers mutual
+ authentication and also protection for integrity, confidentiality,
+ and modification protection for subsequent traffic exchanges.
+
+ In order to avoid forceful disconnections of legitimate WTPs after a
+ successful Connection, the AC ignores Capabilities messages received
+ with a previously registered WTP identification.
+
+ State transition: Connection -> Configuration
+ WTP: Upon successful establishment of security infrastructure
+ marked by sending of a Configuration Request message
+ AC: Upon receiving Configuration Request message from a WTP
+ after successful establishment of security infrastructure
+
+ State transition: Connection -> Capabilities Exchange
+ WTP: Upon expiry of the WTP Response Timer before receipt of a
+ positive Connection Response message from an AC or upon
+ receipt of a negative Connection Response message
+ AC: Upon expiry of AC Response Timer before receipt of
+ Configuration Request message from WTP
+
+
+
+
+
+
+Iino, et al. Historic [Page 39]
+
+RFC 5414 WiCoP February 2010
+
+
+5.4. Configuration
+
+ The Configuration state is one in which relatively long-term
+ operational parameters, such as those for identification and logical
+ groups, are exchanged. These parameters are based on previously
+ exchanged capabilities information and network policies.
+
+ The WTP sends a Configuration Request message to the AC.
+
+ The AC first acknowledges the WTP's Configuration Request, after
+ which it sends appropriate configuration information in subsequent
+ Configuration Data messages. WiCoP includes MIB objectives as
+ message elements in some Configuration Data messages so as to
+ simplify WTP configuration.
+
+ The WTP acknowledges Configuration Data messages individually or en
+ bloc with Configuration Data Response messages. The Response Timer
+ is maintained at both WTP and AC to track the exchanges.
+
+ The AC also establishes relevant processing schedules according to
+ the WTP's architecture design. For example, for Split MAC WTPs, the
+ AC arranges its processing schedule to parse IEEE 802.11 control and
+ management messages while for Local MAC WTPs, the AC arranges
+ schedules processing so as to bypass parsing of IEEE 802.11
+ management messages.
+
+ The AC sends a Configure Trigger message after sending all relevant
+ configuration information to the WTP.
+
+ The WTP acknowledges a Configure Trigger message with a Configure
+ Trigger Response message before activating the previously exchanged
+ configuration parameters.
+
+ In order to avoid forceful disconnections of legitimate WTPs after
+ successful Configuration, the AC ignores Capabilities messages
+ received with a previously registered WTP identification.
+
+ State transition: Configuration -> Operation
+ WTP: After receiving final Configuration Data message from the
+ AC marked by receipt of a Configure Trigger message from
+ the AC
+ AC: Upon receiving acknowledgement for Configure Trigger
+ message marked by receipt of a Configure Trigger Response
+ message from WTP
+
+ State transition: Configuration -> Capabilities Exchange
+ WTP: Upon expiry of the WTP Response Timer before receipt of a
+ Configure Trigger message from the AC
+
+
+
+Iino, et al. Historic [Page 40]
+
+RFC 5414 WiCoP February 2010
+
+
+ AC: Upon expiry of the AC Response Timer before receipt of
+ Configure Data Response message or Configure Trigger
+ Response message
+
+ The following describes major configuration aspects of WiCoP.
+
+5.4.1. Logical Groups
+
+ Configuration Data messages are used to establish logical groups in
+ the WLAN and also to separate traffic among them. The logical groups
+ are established based on network administrative policies and other
+ external considerations. In the IEEE 802.11 use-case, logical groups
+ are established with BSSID-based virtual APs and are separated over
+ the WiCoP interface using tunnels.
+
+ The AC assigns particular BSSIDs of the WTP to specific VLAN tunnels.
+ This assignment is specified to the WTP using the BSSID-TunnelID
+ parameter in the Configuration Data message. The logical group
+ mapping therefore works across the wireless and WiCoP interfaces.
+
+ The WTP then identifies the specified BSSID and VLAN tunnel as
+ corresponding to one logical group. It creates internal state such
+ that traffic belonging to the logical group is kept distinct from
+ that of other logical groups.
+
+ The AC and WTP also use distinct VLAN tunnels for data and control
+ traffic. The 'C' field in the WiCoP header is used to distinguish
+ and assign WiCoP packets to particular data and control VLAN tunnels.
+
+5.4.2. Resource Control
+
+ The AC sends QoS information using QoS-Value message elements in
+ Configuration Data messages. The QoS-Value message element contains
+ values for EDCA and HCCA parameters. This information is specified
+ for each of the logical groups. In the IEEE 802.11 use-case, QoS-
+ Value message elements are specified for each BSSID.
+
+ The WTP configures QoS parameters locally and also forwards relevant
+ settings to wireless terminals in appropriate encapsulations. In the
+ IEEE 802.11 use-case, QoS parameters are sent to wireless terminals
+ in corresponding Beacon or Probe Response frames.
+
+5.5. Operation
+
+ This is the active operation state of the WLAN in which short-term
+ dynamics are examined.
+
+
+
+
+
+Iino, et al. Historic [Page 41]
+
+RFC 5414 WiCoP February 2010
+
+
+ The WTP begins operations according to the operational parameters
+ exchanged in the previous Configuration state.
+
+ The AC monitors WTPs according to network administrative policies and
+ configurations.
+
+ In order to avoid forceful disconnections of legitimate WTPs after
+ successful Operation setup, the AC ignores Capabilities messages
+ received with a previously registered WTP identification.
+
+ State transition: Operation -> Capabilities Exchange
+ WTP: Upon expiry of the WTP Active Presence Timer before receipt
+ of a Feedback Response message from the AC
+ AC: Upon expiry of the AC Active Presence Timer before receipt
+ of a Feedback message from the WTP
+
+ State transition: Operation -> Initialization
+ WTP: Upon receipt of a Reset message from an AC
+ AC: Upon receipt of a Reset Response message from a WTP
+
+ The following describes major operation aspects of WiCoP.
+
+5.5.1. Updates
+
+ The dynamic nature of WLAN systems requires regular updates to
+ network operations.
+
+ The AC sends additional configuration information in the
+ Configuration Data messages. This is applicable to establishment of
+ new logical groups, changes to existing logical groups, changes in
+ QoS settings, etc. Configuration information is followed by a
+ Configure Trigger message.
+
+ The WTP sends a Configure Trigger Response before activating the
+ additional configuration information.
+
+ Configuration updates can be used to clear statistics information by
+ reflecting initial values.
+
+ An extreme case of a configuration update involves use of the Reset
+ message from the AC, which instructs the WTP to revert to initial
+ conditions. The WTP replies with a Reset Response message before
+ reverting to its initial state.
+
+5.5.2. Feedback and Statistics
+
+ The Operation state also sees regular feedback being sent by WTPs to
+ the AC.
+
+
+
+Iino, et al. Historic [Page 42]
+
+RFC 5414 WiCoP February 2010
+
+
+ The WTP sends Feedback messages to indicate various statistics and
+ congestion condition information. Feedback also includes information
+ on the state of the WTP and wireless medium such as queue levels and
+ channel interference. Feedback messages are sent with a frequency
+ defined by the Feedback Interval. In addition to statistics, the
+ Feedback message also serves as a WTP keepalive indicator to the AC.
+ Feedback messages combine statistics information together with WTP
+ status information.
+
+ The AC monitors Feedback messages for their statistics value and
+ implicit indication of WTP activity. The AC also tracks the state of
+ congestion at wireless terminals and WTPs. This information enables
+ the AC to adapt its downstream transmissions, such as scheduling
+ transmission away from congested WTPs, so as to relieve congestion.
+
+ The AC additionally uses the Feedback message to randomly determine
+ the active state of WTPs. An active WTP replies with a corresponding
+ Feedback Response message.
+
+5.5.3. Non-Periodic Events
+
+ The WTP and AC use the Notification message for non-periodic events.
+ They send Notification messages to indicate error conditions or
+ drastic changes in congestion state.
+
+ The recipient of the Notification message acknowledges with a
+ Notification Response message. The response may contain information
+ on rectifying the error or may simply be an acknowledgement of the
+ Notification.
+
+5.5.4. Firmware Trigger
+
+ The AC sends a Firmware Download message to update firmware at WTPs.
+ The Firmware Download message contains TFTP information, which the
+ WTP uses to refresh its firmware. This is used when a new version of
+ firmware is available for the WTPs.
+
+ The WTP acknowledges new firmware with a Firmware Download Response
+ message after which it is activated.
+
+5.5.5. Wireless Terminal Management
+
+ The Operation state of WiCoP also involves configuration of WTPs and
+ the AC with wireless terminal-specific information.
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 43]
+
+RFC 5414 WiCoP February 2010
+
+
+ Here the Terminal Addition message is used in response to a new
+ wireless terminal entering the WLAN. This message may be sent by
+ either the WTPs or the AC, depending on the WiCoP interface being
+ used. The recipient of this message replies with the Terminal
+ Addition Response message.
+
+ The Terminal Deletion message is used when a wireless terminal leaves
+ the WLAN. This is used to delete state information that was
+ maintained by either the WTPs or the AC. It is acknowledged with the
+ Terminal Deletion Response message.
+
+ Figure 8 below illustrates the exchange of Terminal Addition and
+ Terminal Deletion messages for both Local-MAC- and Split-MAC-based
+ WiCoP interfaces.
+
+ Here the WiCoP Terminal Addition message is triggered as a response
+ to an IEEE 802.11 Association message. In the case of Local MAC
+ architecture, the WTP sends the message to the AC. However, in the
+ Split MAC architecture, Terminal Addition is sent from an AC to the
+ WTP.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 44]
+
+RFC 5414 WiCoP February 2010
+
+
+ +----------+ +---------------+ +------+
+ | Terminal | | Local MAC WTP | | AC |
+ +----------+ +---------------+ +------+
+ | | |
+ | | |
+ | IEEE 802.11 Association | WiCoP |
+ |------------------------->| Terminal Addition |
+ | |===========================>|
+ | | |
+ | | WiCoP Terminal |
+ | |<===========================|
+ | IEEE 802.11 Association | Addition Response |
+ |<-------------------------| |
+ | Response | |
+ | | |
+ | | |
+ | |
+ | |
+ | |
+ | +---------------+ |
+ | | Split MAC WTP | |
+ | +---------------+ |
+ | | |
+ | | |
+ | IEEE 802.11 Association | |
+ |------------------------->| |
+ | | IEEE 802.11 Association |
+ | |===========================>|
+ | | (Over WiCoP) |
+ | | |
+ | | |
+ | | WiCoP |
+ | | Terminal Addition |
+ | |<===========================|
+ | | |
+ | | |
+ | | WiCoP Terminal |
+ | |===========================>|
+ | | Addition Response |
+ | | |
+ | | |
+ | | IEEE 802.11 Association |
+ | |<===========================|
+ | | Response (Over WiCoP) |
+ | IEEE 802.11 Association | |
+ |<-------------------------| |
+ | Response | |
+ Figure 8
+
+
+
+Iino, et al. Historic [Page 45]
+
+RFC 5414 WiCoP February 2010
+
+
+5.5.6. Key Configuration
+
+ One of the differences between Split MAC and Local MAC WTPs is the
+ location of the over-the-air encryption. Some Split MAC and Local
+ MAC WTPs perform encryption locally while others leave it to the AC.
+ WiCoP accommodates these differences by enabling security key
+ configuration in those cases where encryption is performed at the
+ WTP. The encryption setup process is therefore contingent on the
+ WiCoP protocol interface.
+
+ When dynamic WEP is used, the WiCoP Key Configuration message is used
+ to notify WTPs of encryption keys for each associated wireless
+ terminal. Here, the EAP over LAN (EAPoL) Key frame is encapsulated
+ in the Key Configuration message and sent to a WTP. Upon receiving
+ the Key Configuration message, the WTP sets the encryption key in its
+ local security table, decapsulates the EAPOL Key frame and forwards
+ it to the wireless terminal. This is illustrated in Figure 9.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 46]
+
+RFC 5414 WiCoP February 2010
+
+
+ +----------+ +-----+ +------+
+ | Terminal | | WTP | | AC |
+ +----------+ +-----+ +------+
+ | | |
+ | 802.1x Authentication |
+ |<=====================================================>|
+ | | |
+ | | |
+ PMK | PMK
+ | | |
+ | | |
+ |<-------------------------|<===========================|
+ | EAPoL Packet | WiCoP Control Packet |
+ | | (Key Configuration) |
+ | | | +-----------------------+
+ | | \|- Encryption-Data |
+ | | | Unicast-Key |
+ Set Receive |- EAP-Frame |
+ Unicast-Key Unicast-Key | Key Signature |
+ | | +-----------------------+
+ | | |
+ | |===========================>|
+ | | WiCoP Control Packet |
+ | | (Key Configuration |
+ | | Response ) |
+ | | |
+ | | |
+ | | |
+ | | |
+ |<-------------------------|<===========================|
+ | EAPoL Packet | WiCoP Control Packet |
+ | | (Key Configuration) |
+ | | | +-----------------------+
+ | | \|- Encryption-Data |
+ | | | Broadcast-Key |
+ Set Receive |- EAP-Frame |
+ Broadcast-Key Broadcast-Key | Key Signature |
+ | | | Broadcast Key |
+ | | +-----------------------+
+ | | |
+ | |===========================>|
+ | | WiCoP Control Packet |
+ | | (Key Configuration |
+ | | Response ) |
+
+ Figure 9
+
+
+
+
+
+Iino, et al. Historic [Page 47]
+
+RFC 5414 WiCoP February 2010
+
+
+ When WPA or IEEE 802.11i is used in WLAN architectures in which the
+ authenticator is located at the AC and encryption points at WTPs, the
+ exchanges of the 4-way handshake are managed distinctly. This is
+ because the AC is no longer in a position to calculate the KeyMIC as
+ it is not aware of the KeyRSC sequence counter. So here, a WiCoP Key
+ Configuration message is used to transport the 3rd message of the
+ 4-way handshake -- containing the EAPoL-Key -- with unassigned KeyRSC
+ and KeyMIC fields. When the WTP receives the WiCoP Key Configuration
+ message, it first assigns the sequence number value to the KeyRSC
+ field. Then, the WTP calculates the KeyMIC value using the PTK and
+ KeyRSC. So, the WiCoP Key Configuration message allows the KeyMIC to
+ be calculated at the WTPs instead of the AC. The GTK-Flag message
+ element is used to determine how the KeyMIC is calculated -- in case
+ of a new GTK, KeyMIC is computed with a KeyRSC value of 0 and in case
+ of an existing GTK, KeyMIC is computed with a KeyRSC value
+ corresponding to the actual counter.
+
+ Figure 10 illustrates this case where the WiCoP common header is
+ either 'M' = 0 and 'D' = 0 or 'M' = 1 and 'D' = 1.
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+Iino, et al. Historic [Page 48]
+
+RFC 5414 WiCoP February 2010
+
+
+ +----------+ +-----+ +------+
+ | Terminal | | WTP | | AC |
+ +----------+ +-----+ +------+
+ | | |
+ | 802.1x Authentication |
+ |<=====================================================>|
+ | | |
+ PMK | PMK
+ | | |
+ Generate | Generate
+ SNonce | ANonce
+ | | |
+ | | |
+ | Message 1 |
+ |<-------------------------|<---------------------------|
+ | EAPoL Packet | WiCoP Data Packet |
+ Receive | |
+ ANonce | |
+ Generate | |
+ PTK | |
+ | | |
+ | Message 2 |
+ |------------------------->|--------------------------->|
+ | EAPoL Packet | WiCoP Data Pakcet |
+ | | Receive
+ | | SNonce
+ | | |
+ | | Generate
+ | | PTK
+ | | GTK
+ | Message 3 |
+ |<-------------------------|<===========================|
+ | EAPoL Packet | WiCoP Control Packet |
+ | | (Key Configuration) |
+ | | | +-----------------------+
+ | | \|- GTK-Flag |
+ Receive Receive |- Encryption-Data(PTK) |
+ GTK PTK |- Encryption-Data(GTK) |
+ | GTK |- EAP-Frame |
+ | | +-----------------------+
+ | | |
+ | | |
+ | | |
+ | Message 4 |
+ |------------------------->|--------------------------->|
+ | EAPoL Packet | WiCoP Data Pakcet |
+ | | |
+ Figure 10
+
+
+
+Iino, et al. Historic [Page 49]
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+RFC 5414 WiCoP February 2010
+
+
+ The 1st, 2nd, and 4th messages of the 4-way handshake are transported
+ in WiCoP data packets that are assigned priorities similar to that of
+ WiCoP control packets.
+
+ Similarly, for the group key handshake in WPA and IEEE 802.11i, the
+ 1st message of the handshake is transported using the WiCoP Key
+ Configuration message with unassigned KeyRSC. The WTP again assigns
+ the sequence number value to the KeyRSC and then calculates the
+ KeyMIC. The 2nd message of the handshake however is transported in
+ WiCoP data packets with priorities similar to that of WiCoP control
+ packets. This is illustrated in Figure 11.
+
+ +----------+ +-----+ +------+
+ | Terminal | | WTP | | AC |
+ +----------+ +-----+ +------+
+ | | |
+ | Message 1 |
+ |<-------------------------|<===========================|
+ | EAPoL Packet | WiCoP Control Packet |
+ | | (Key Configuration) |
+ | | | +-----------------------+
+ | | \|- GTK-Flag |
+ Receive Receive |- Encryption-Data(GTK) |
+ GTK GTK |- EAP-Frame |
+ | | +-----------------------+
+ | | |
+ | | |
+ | | |
+ | | |
+ | Message 2 |
+ |------------------------->|--------------------------->|
+ | EAPoL Packet | WiCoP Data Pakcet |
+ | | |
+
+ Figure 11
+
+ The Key Configuration Response message is used by the WTP to notify
+ the AC of the encryption setup process.
+
+
+
+
+
+
+
+
+
+
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+Iino, et al. Historic [Page 50]
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+RFC 5414 WiCoP February 2010
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+
+6. WiCoP Performance
+
+ WiCoP is an efficient protocol. This section illustrates various
+ examples of its efficiency.
+
+6.1. Operational Efficiency
+
+ The fact that WiCoP requires a single operation to distinguish and
+ manage WTPs of different designs makes it operationally efficient.
+ Because WiCoP assigns dedicated classification bits in the common
+ header, an AC needs to parse incoming packets only once to determine
+ the particular manner in which it is to be processed. Without the
+ dedicated classifications in the common header, an AC would have to
+ perform a lookup after parsing every incoming packet, which would
+ result in delaying processing. The scale and sensitivity of large-
+ scale deployments require that WLAN control protocols be efficient in
+ operation.
+
+6.2. Semantic Efficiency
+
+ In certain cases, WiCoP combines utilities in a single operation.
+ One particular case is that of statistics and activity feedback.
+ Here, WTPs regularly send a single Feedback message containing
+ statistics and other state information, which also acts as an
+ implicit keepalive mechanism. This helps to reduce the number of
+ message exchanges and also simplifies protocol implementation.
+ Similarly, the Capabilities messages serve the purpose of finding ACs
+ as well as informing them of WTP capabilities and design.
+
+7. Summary and Conclusion
+
+ The Wireless LAN Control Protocol presents a solution for managing
+ large-scale WLANs with diverse elements. It addresses the challenges
+ presented in the CAPWAP Problem Statement [RFC3990] and realizes the
+ requirements of the CAPWAP Objectives [RFC4564].
+
+ WiCoP enables integral control of Split MAC and Local MAC WTPs by
+ defining appropriate differentiators within the protocol message
+ exchanges and processes. It addresses architecture designs in which
+ the authenticator and encryption points are located on distinct
+ entities. In doing so, WiCoP realizes the interoperability objective
+ and its benefits.
+
+ WiCoP also addresses shared WLAN deployments by configuring and
+ managing WTPs on a logical group basis. It is further provisioned to
+ separate control and data traffic within WLANs. So, the protocol
+ addresses the objectives of logical groups and traffic separation.
+
+
+
+
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+
+ Overall, the specifications presented in this document allow for an
+ effective WLAN control and provisioning protocol.
+
+8. Security Considerations
+
+ Illegitimate WTPs and ACs pose a significant threat to WLAN security.
+ This can be mitigated by requiring all WiCoP entities to be mutually
+ authenticated before initiating critical protocol exchanges. WiCoP
+ includes a trigger for a suitable authentication mechanism. This is
+ to accommodate a different security mechanism that may be used
+ between WTPs and the AC, depending on the nature of the deployment.
+
+ In extension to mutual authentication, the subsequent exchange of
+ protocol information between WTPs and the AC need to be protected.
+ The exchanges have to be protected against alterations of any sort
+ and Denial-of-Service (DoS) attacks. Also, the information should
+ not be accessible to any third party. Encryption of protocol
+ exchanges is therefore necessary. WiCoP includes appropriate
+ procedures to select and establish a security association between
+ WTPs and the AC in the Connection state.
+
+ Architecture designs in which authentication is performed at the AC
+ and encryption at the WTPs can be exposed to the threat of replay
+ attacks. Since the AC will not be aware of the exact value of the
+ sequence counter, it will not make the corresponding assignment
+ within the 4-way handshake. This leaves the wireless terminal to
+ accept all incoming frames, including illegitimate frames, as it
+ cannot verify the sequence counter value. Such a threat needs to
+ protected against by allowing the WTP to assign the correct value of
+ the sequence counter. WiCoP accomplishes this by sending the 3rd
+ message of the 4-way handshake within a control message to the WTP,
+ which then updates the sequence counter field before forwarding it to
+ the wireless terminals.
+
+ Another issue to consider is that of rogue WTPs using identifiers
+ similar to that of legitimate WTPs. In such instances, a rogue WTP
+ can send a Capabilities message to the AC, thereby causing
+ disconnection of the existing legitimate WTP of the same identifier.
+ It is important for the AC to ignore Capabilities messages received
+ with existing identifiers.
+
+
+
+
+
+
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+RFC 5414 WiCoP February 2010
+
+
+9. Informative References
+
+ [RFC4118] Yang, L., Zerfos, P., and E. Sadot, "Architecture Taxonomy
+ for Control and Provisioning of Wireless Access Points
+ (CAPWAP)", RFC 4118, June 2005.
+
+ [RFC4564] Govindan, S., Ed., Cheng, H., Yao, ZH., Zhou, WH., and L.
+ Yang, "Objectives for Control and Provisioning of Wireless
+ Access Points (CAPWAP)", RFC 4564, July 2006.
+
+ [RFC3990] O'Hara, B., Calhoun, P., and J. Kempf, "Configuration and
+ Provisioning for Wireless Access Points (CAPWAP) Problem
+ Statement", RFC 3990, February 2005.
+
+
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+RFC 5414 WiCoP February 2010
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+Authors' Addresses
+
+ Satoshi Iino
+ Panasonic Mobile Communications
+ 600, Saedo-cho
+ Tsuzuki-ku
+ Yokohama 224 8539
+ Japan
+
+ Phone: +81 45 938 3789
+ EMail: iino.satoshi@jp.panasonic.com
+
+
+ Saravanan Govindan
+ Panasonic Singapore Laboratories
+ Block 1022, Tai Seng Industrial Estate
+ #06-3530, Tai Seng Avenue
+ Singapore 534 415
+ Singapore
+
+ Phone: +65 6550 5441
+ EMail: saravanan.govindan@sg.panasonic.com
+
+
+ Mikihito Sugiura
+ Panasonic Mobile Communications
+ 600, Saedo-cho
+ Tsuzuki-ku
+ Yokohama 224 8539
+ Japan
+
+ Phone: +81 45 938 3789
+ EMail: sugiura.mikihito@jp.panasonic.com
+
+
+ Hong Cheng
+ Panasonic Singapore Laboratories
+ Block 1022, Tai Seng Industrial Estate
+ #06-3530, Tai Seng Avenue
+ Singapore 534 415
+ Singapore
+
+ Phone: +65 6550 5447
+ EMail: hong.cheng@sg.panasonic.com
+
+
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+Iino, et al. Historic [Page 54]
+