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Versions: (draft-nadeau-pwe3-vccv) 00 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 RFC 5085

Network Working Group                                     T. Nadeau (Ed)
Internet Draft                                         C. Pignataro (Ed)
Expiration Date: July 2007                           Cisco Systems, Inc.

                                                        R. Aggarwal (Ed)
                                                        Juniper Networks




                                                           January 2007

      Pseudo Wire Virtual Circuit Connectivity Verification (VCCV)


                      draft-ietf-pwe3-vccv-12.txt



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Abstract

   This document describes Virtual Circuit Connection Verification
   (VCCV) which provides a control channel that is associated
   with a Pseudowire (PW), as well as the corresponding
   operations and management functions such as connectivity
   verification to be used over that control channel. VCCV
   applies to all supported access circuit and transport types
   currently defined for PWs.




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Table of Contents

 1     Specification of requirements  ..........................   4
 2     Introduction  ...........................................   4
 3     Overview of VCCV  .......................................   5
 4     CC Types and CV Types ...................................   5
 4.1   Bidirectional Forwarding Detection ......................   7
 4.1.1 BFD Encapsulation .......................................   7
 5     VCCV Control Channel for MPLS PSN .......................   7
 5.1   Inband VCCV (Type 1) ....................................   7
 5.2   Out-of-Band VCCV (Type 2) ...............................   8
 5.3   TTL Expiry VCCV (Type 3) ................................   8
 5.4   VCCV Connectivity Verification Types ....................   8
 5.4.1 MPLS LSP Ping ...........................................   9
 5.5   VCCV Capability Advertisement for MPLS PSN ..............  10
 5.5.1 VCCV Capability Advertisement LDP Sub-TLV ...............  11
 6     VCCV Control Channel for L2TPv3/IP PSN  .................  12
 6.1   L2TPv3 VCCV Message  ....................................  13
 6.1.1 L2TPv3 VCCV using ICMP Ping  ............................  13
 6.1.2 L2TPv3 VCCV using BFD  ..................................  13
 6.2   L2TPv3 VCCV Capability Indication  ......................  13
 6.2.1 L2TPv3 VCCV Capability AVP  .............................  13
 6.3   L2TPv3 VCCV Operation  ..................................  14
 7.    Capability Advertisement Preference Order ...............  14
 8.    IANA Considerations  ....................................  14
 8.1   VCCV Parameter ID  ......................................  14
 8.1.1 Control Channel Types (CC Types) ........................  15
 8.1.2 Connectivity Verification Types (CV Types) ..............  15
 8.1.3 Channel Type  ............................ ..............  15
 8.2   L2TPv3 Assignments  .....................................  15
 8.2.1 Control Message Attribute Value Pairs (AVPs)  ...........  15
 8.2.2 Default L2-Specific Sublayer bits  ......................  15
 8.2.3 ATM-Specific Sublayer bits  .............................  15
 8.2.4 VCCV Capability AVP Values  .............................  15
 9     Security Considerations  ................................  15
 10    Acknowledgements  .......................................  17
 11    References  .............................................  17
 11.1  Normative References  ...................................  17
 11.2  Informative References  .................................  18
 12    Editor Information ......................................  18
 13    Contributor Information  ................................  19
 14    Intellectual Property Statement  ........................  20
 15    Full Copyright Statement  ...............................  20


1. Specification of requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",



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   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in [RFC2119].

2. Introduction

   As network operators deploy Pseudowire (PW) services, fault detec-
   tion and diagnostic mechanisms particularly for the PSN portion of
   the network are pivotal. Specifically, the ability to provide end-to-
   end fault detection and diagnostics for an emulated PW service is
   critical for the network operator. Operators have indicated in
   [RFC4377][RFC3916] that such a tool is required for PW deployments.
   This document describes procedures for a PSN-agnostic fault
   detection and diagnostics tool called Virtual Circuit Connection
   Verification (VCCV).

            |<-------------- Emulated Service ---------------->|
            |          |<---------- VCCV ---------->           |
            |          |<------- Pseudowire ------->|          |
            |          |                            |          |
            |          |    |<-- PSN Tunnel -->|    |          |
            |          V    V                  V    V          |
            V    AC    +----+                  +----+     AC   V
      +-----+    |     | PE1|==================| PE2|     |    +-----+
      |     |----------|............PW1.............|----------|     |
      | CE1 |    |     |    |                  |    |     |    | CE2 |
      |     |----------|............PW2.............|----------|     |
      +-----+  ^ |     |    |==================|    |     | ^  +-----+
            ^  |       +----+                  +----+     | |  ^
            |  |   Provider Edge 1         Provider Edge 2  |  |
            |  |                                            |  |
      Customer |                                            | Customer
      Edge 1   |                                            | Edge 2
               |                                            |
               |                                            |
         Native service                               Native service

               Figure 1: PWE3 VCCV Operation Reference Model

   Figure 1 depicts the basic functionality of VCCV, and where it
   resides within the PWE3 VCCV Operation Reference Model [RFC3985].
   Customer Edge (CE) routers CE1 and CE2 are attached to the emulated
   service via Access Circuits (ACs) to each of the Provider Edge (PE)
   Routers (PE1 and PE2). These PEs are in-turn, connected via a
   Pseudowire (PW) that traverses the provider network. VCCV provides
   several means of creating a control channel between PE routers that
   attach the PW.





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      +-------------+                                +-------------+
      |  Layer2     |                                |  Layer2     |
      |  Emulated   |       < Emulated Service >     |  Emulated   |
      |  Services   |                                |  Services   |
      +-------------+                                +-------------+
      |             |            VCCV/PW             |             |
      |Demultiplexer|       < Control Channel >      |Demultiplexer|
      +-------------+                                +-------------+
      |    PSN      |          < PSN Tunnel >        |    PSN      |
      +-------------+                                +-------------+
      |  Physical   |                                |  Physical   |
      +-----+-------+                                +-----+-------+
            |                                              |
            |             ____     ___        ____         |
            |           _/    ___/    \    _/     __       |
            |          /               \__/        _       |
            |         /                              \     |
            ---------|      MPLS or IP Network        |-----
                     |                               /
                     |    ___      ___     __   ___/
                      \_/   ____/   ___/  ____/

         Figure 2: PWE3 Protocol Stack Reference Model
                   including the VCCV control channel.

   Figure 2 depicts how the VCCV control channel is associated with the
   Pseudowire. Ping and other IP messages are encapsulated using the
   PWE3 encapsulation as described below in sections 5 and 6. These mes-
   sages, referred to as VCCV messages, are exchanged only after the
   desire to exchange such traffic has been negotiated between the PEs
   (see Section 7).


3. Overview of VCCV

   VCCV defines a set of messages that are exchanged between PEs to ver-
   ify connectivity of the Pseudowire. To make sure that VCCV packets
   follow the same path as the PW data flow, they SHOULD be encapsulated
   with the same PW demultiplexer and trasported over the same PSN
   tunnel.  For example, if MPLS is the PSN in use, then the same
   label shim header (and label stack) MUST be incorporated.  The only
   cases where this might not be possible is when out-of-band VCCV modes
   are used which require this encapsulation to be altered; however,
   these modes are NOT RECOMMENDED.

   VCCV can be used both as a fault detection and/or a diagnostic
   tool for Pseudowires. An operator can periodically invoke VCCV
   for proactive connectivity verification on an active Pseudowire,



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   or on an ad hoc or as-needed as a means of manual
   connectivity verification.  When invoking VCCV, the operator
   triggers a combination of one of its various Connectivity Check
   types (CC Type) and one of its various Connectivity Verification
   (CV) Types. These include LSP-Ping, L2TPV3, or ICMP Ping [RFC792]
   modes and are applicable depending on the underlying PSN.

   Since a Pseudowire service is bi-directional, the reply MAY be sent
   in-band over the PW in the reverse direction. Responses MUST
   be encapsulated so that they follow the return path of
   the Pseudowire in this case. In-band responses MUST be attempted
   first. If an in-band test fails, the operator is advised to
   then use a subsequent test using an out-of-band reply mode such
   as Reply Mode 4 from [RFC4379], which will return the result
   to the sender via an application level control channel to
   determine the fault's direction.

   The control channel maintained with VCCV can carry fault detection
   status across a Pseudowire and convey this information between
   the endpoints of the Pseudowire. Furthermore, this information
   can then be translated into the native OAM status codes used by
   the native access technologies, such as ATM or Ethernet. The
   specific details of such status interworking is out of the scope
   of this document, and is only noted here to illustrate the
   utility of VCCV for such purposes. More complete details can
   be found in [OAM-MAP].


4. CC Types and CV Types

   VCCV can support several types of connectivity verification types (CV
   types) or protocols within several possible control channel as
   defined by the control channel type (CC types), but it does not
   support the use of more than one combination of both concurrently.
   The specific type or types of VCCV packets accepted by a router are
   indicated during capability advertisement as described in sections
   5.5 and 6.2. The various VCCV CV types supported MUST be used
   only when they apply to the context of the PW demultiplexor in use.
   For example, LSP Ping type should only be used when MPLS is utilized
   as the PSN.

   Once a set of capabilities if advertised, the specific one chosen
   based on the preferred order specified below in section 7. Once
   a specific CC and CV type combination has been chosen, transmitted
   and replied to, this type combination MUST be the only one used
   until such time as the Pseudowire is re-signaled. Based on these
   rules and the procedures defined in [RFC4447], the Pseudowire MUST
   be re-signaled if a different set of capabilities types is desired.



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   The CC and CV type indicator fields are defined as a bitmasks
   used to indicate the specific CC or CV type or types (i.e.: none,
   one or more) of control channel packets that may be sent on
   the VCCV control channel. These values represent the numerical
   value corresponding to the actual bit being set in the
   bitfield. The definintion of each CC and CV Type is dependent
   on the context within which it is defined; please refer to
   the specific MPLS or L2TPv3 sections below.

   The defined values for CC Types are for MPLS PWs are:

       Bit 0 (0x01) - Type 1: PWE3 control word with 0001b
                      as first nibble as defined in [RFC4385].
       Bit 1 (0x02) - Type 2: MPLS Router Alert Label.
       Bit 2 (0x04) - Type 3: MPLS PW Demultiplexor Label
                      TTL = 1 (Type 3).
       Bit 3 (0x08) - Reserved
       Bit 4 (0x10) - Reserved
       Bit 5 (0x20) - Reserved
       Bit 6 (0x40) - Reserved
       Bit 7 (0x80) - Reserved

   The defined values for CC Types are for L2TPv3 PWs are:

       Bit 0 (0x01) - L2-Specific Sublayer with V-bit set.
       Bit 1 (0x02) - Reserved
       Bit 2 (0x04) - Reserved
       Bit 3 (0x08) - Reserved
       Bit 4 (0x10) - Reserved
       Bit 5 (0x20) - Reserved
       Bit 6 (0x40) - Reserved
       Bit 7 (0x80) - Reserved

   The defined values for CV Types are for MPLS PWs are:

       Bit 0 (0x01) - ICMP Ping.
       Bit 1 (0x02) - LSP Ping.
       Bit 2 (0x04) - BFD for PW Fault Detection Only.
       Bit 3 (0x08) - BFD for PW Fault Detection and AC/PW Fault
                      Status Signaling.
       Bit 4 (0x10) - BFD for PW Fault Detection Only. Carrying
                      BFD payload without IP headers.
       Bit 5 (0x20) - BFD for PW Fault Detection and AC/PW Fault
                      Status Signaling. Carrying BFD payload
                      without IP headers.
       Bit 6 (0x40) - Reserved
       Bit 7 (0x80) - Reserved



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   The defined values for CV Types are for L2TPv3 PWs are:

       Bit 0 (0x01) - ICMP Ping.
       Bit 1 (0x02) - Reserved
       Bit 2 (0x04) - BFD for PW Fault Detection Only.
       Bit 3 (0x08) - BFD for PW Fault Detection and AC/PW Fault
                      Status Signaling.
       Bit 4 (0x10) - BFD for PW Fault Detection Only. Carrying BFD
                      payload without IP headers.
       Bit 5 (0x20) - BFD for PW Fault Detection and AC/PW Fault
                      Status Signaling. Carrying BFD payload without
                      IP headers.
       Bit 6 (0x40) - Reserved
       Bit 7 (0x80) - Reserved

   It should be noted that two different pairs of CV Types have been
   defined when BFD is used. If a capability advertisement is received
   with both 0x04 and 0x08 types indicated, the receiving PE MUST ignore
   the 0x04 bit as if it were set to 0 unless it cannot support the
   transmission of type 0x08. If a capability advertisement is
   received with both 0x10 and 0x20 types indicated, the PE MUST ignore
   the 0x20 bit as if it were set to 0. In the case of type 0x08 or
   0x20, the AC and PW status SHOULD be conveyed via BFD status codes
   as specified in [OAM-MAP].  However, this type SHOULD NOT be used
   when a control protocol such as LDP or L2TPV3 is available that can
   signal the AC/PW status to the remote endpoint of the PW
   In the case of type 0x04 or 0x10, BFD is used exclusively to detect
   faults on the PW and the status of those faults should be conveyed
   using some means other than BFD, such as using LDP status messages
   when using MPLS as a transport, or the Circuit Status
   AVP in an L2TPv3 SLI message for L2TPv3 (see [RFC3931]).
   If none of the types above are supported, the entire CC and CV Type
   Indicator fields SHOULD be transmitted as 0x00 (i.e.: all bits in
   the bitfield set to 0) to indicate this to the peer.

   If no capability is signaled, then the peer MUST assume that
   the peer has no VCCV capability and follow the procedures
   specified in this document for this case.

4.1 Bidirectional Forwarding Detection

   When heart-beat indication is necessary for one or more PWs, the
   Bidirectional Forwarding Detection (BFD) [BFD] provides a
   means of continuous monitoring of the PW data path and
   propagation of forward and reverse defect indications.

   In order to use BFD, both ends of the PW connection must have



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   signaled the existence of a control channel and the ability to run
   BFD on it. Once a node has both signaled and received signaling from
   its peer of these capabilities, it MUST begin sending BFD control
   packets. The packets MUST be sent on the control channel. The use
   of the control channel provides the context required to bind and
   bootstrap the BFD session, thus single-hop BFD initialization
   procedures are followed [BFD], and BFD MUST be run in asynchronous
   mode [BFD].

   When one of the PEs (PE2 from Figure 1) does not receive control
   messages from its peer PE (PE1 from Figure 1) during a certain
   number of transmission intervals (a number provisioned by the
   operator) PE2 declares that the PW in its receive direction is down.
   In other words, PE1 enters the "forward defect" state for this PW.
   PE1 then sends a message to PE2 with H=0 (i.e. "I do not hear you")
   and with Diagnostic code 1. In turn, PE2 declares the PW is down in
   its transmit direction and it uses Diagnostic code 3 in its control
   messages to PE1. PE2 enters the "reverse defect" state for this PW.
   How it further processes this error condition, and conveys this
   status the attachment circuits is out of the scope of this
   specification, and is instead defined in [OAM-MAP].

   The VCCV message comprises a BFD packet [BFD] encapsulated
   as specified by the CV Type (see Section 4.1.1).

4.1.1 BFD Encapsulation

   VCCV defines two pairs of CV Types (see above) which specify
   two ways in which the VCCV control channel may be encapsualted
   when carrying a BFD payload. When the CV Type is either 0x04 or
   0x08, the VCCV encapsulation includes the IP/UDP encapsulation
   as defined in Section 4 of [BFDV4V61HOP]. However, when CV Type
   0x10 or 0x20 is employed, the IP/UDP headers are omitted.
   In these cases the corresponding PW CW's or L2SS'
   Channel Type field MUST use the value defined in Section
   8.1.3 as a means of allowing the data plane to demultiplex
   the control channel and identify the encased BFD payload.


5. VCCV Control Channel for MPLS PSN

   When MPLS is used to transport PW packets, VCCV packets are
   carried over the MPLS LSP as defined in this section.
   In order to apply IP monitoring tools a PWE3 PW, an operator
   may configure VCCV as a control channel for the PW between
   the PEs endpoints [RFC3985].  Packets sent across this channel
   from the source PE towards the destination PE either as in-band
   traffic with the PW's data, or out-of-band. In all cases, the



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   control channel traffic MUST NOT be forwarded past the PE
   endpoints towards the Customer Edge (CE) devices; instead,
   they must be intercepted at the PE endpoints for exception
   processing.

   The capability of which control channel type (CC Type) to
   use is advertised by a PE to indicate which of the various
   control channel types are supported. Once the receiving PE
   has chosen a mode to use, it MUST continue using this mode
   until such time as the PW is re-signaled. Thus, if a new CC
   type is desired, the PW must be torn-down and re-established.

   Ideally such a control channel would be completely inband. When
   a control word is present on the PW, it is possible to indi-
   cate the control channel by setting a bit in the control word
   header.

   The following subsections define each of
   the currently defined VCCV Control Channel Types (CC Types).

5.1. Inband VCCV (Type 1)

   The PW set-up protocol [RFC4447] determines whether a PW uses a
   control word. When a control word is used, it SHOULD have the
   following form for the purpose of indicating VCCV control
   channel messages. Note that for data, one uses the control
   word defined just above the MPLS payload [RFC4385].

   The PW Associated Channel for VCCV control channel traffic is
   defined as follows in [RFC4385]:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0 0 0 1|Version|   Reserved    |         Channel Type          |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

                  Figure 3: PW Associated Channel Header

   The first nibble is set to 0001b to indicate a channel associated
   with a Pseudowire [RFC4385][RFC4446]. The Version and the Reserved
   fields are set to 0, and the Channel Type is set to 0x0021 for
   IPv4 and 0x0056 for IPv6 payloads. If the payload contains
   BFD without IP/UDP headers, it MUST use 0x0007 as the Channel Type
   (see Section 8.1.3).

   For example, the following is an example of how the ethernet
   ACH would be received [RFC4448] containing an LSP Ping payload



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   corresponding to a choice of CC Type of 0x01 and a CV Type of
   0x02:

       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
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |0 0 0 1|0 0 0 0|0 0 0 0 0 0 0 0|    0x21 (IPv4) 0x56 (IPv6)    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

        Figure 4: PW Associated Channel Header for VCCV


   It should be noted that although some PW types are not required
   to carry the control word, this type of VCCV MUST only be used
   for those PW types that do employ the control word when it is
   in use.

   This is the preferred mode of VCCV operation when the control word
   is present.


5.2. Out-of-Band VCCV (Type 2)

   A VCCV control channel can alternatively be created by using the
   MPLS router alert label [RFC3032] immediately above the PW label.
   It should be noted that this approach MAY result in a differnt
   equal cost multi-path (ECMP) hashing behavior than Pseudowire
   PDUs and thus result in the VCCV control channel traffic taking
   a path which differs from that of the actual data traffic under
   test.

   This is the preferred mode of VCCV operation when the control word
   is not present.

5.3. TTL Expiry VCCV (Type 3)

   The TTL of the PW label can be set to 1 to force the packet to be
   processed within the destination router's control plane. This is
   an inband control channel identification mechanism that is an
   alternate to Section 5.1.

   To use this type, the control word MUST be used.

5.4 VCCV Connectivity Verification Types

5.4.1 MPLS LSP Ping

   The LSP Ping header MUST be used in accordance with [RFC4379]



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   and MUST also contain the target FEC Stack containing the
   sub-TLV of 8 for the "L2 VPN endpoint", 9 (deprecated) or 10 for
   "FEC 128 Pseudowire" or 11 for the "FEC 129 Pseudowire". The
   sub-TLV indicates the PW to be verified.


5.5 VCCV Capability Advertisement for MPLS PSN

   To permit the indication of the type or types of PW control chan-
   nel(s), and connectivity verification mode or modes over a particular
   PW, a VCCV parameter is defined below that is used as part of the PW
   establishment signaling.  When a PE signals a PW and desires PW OAM
   for that PW, it MUST indicate this during PW establishment using the
   messages defined below. Specifically, for PE MUST include the VCCV
   interface parameter sub-TLV (0x0C) in the PW setup message [RFC4447].

   The decision of the type of VCCV control channel is left completely
   to the receiving control entity, although the set of choices is
   given by the sender in that it indicates the type or types of
   control channels that it can understand.  The receiver SHOULD
   chose a single control channel type from the choices indicated
   based on the order of preference rules specified below in
   Section 7 and it MUST continue to use this type for
   the duration of the life of the control channel. Changing control
   channel types after one has been established to be in use
   could potentially cause problems at the receiving end, and
   could also lead to interoperability issues, thus it is NOT
   RECOMMENDED.

   When a PE sends a label mapping message for a PW, it uses
   the VCCV parameter to indicate the type of OAM control channels
   and connectivity verification type or types it is willing to
   receive on that PW. The capablity of supporting a control
   channel or channels, and connectivity type or types used
   over that control channel or channels MUST be signaled before
   the remote PE may send VCCV messages, and then only on the
   control channel or channels, and using the connectivity
   verification type or types indicated.

   If a PE receives VCCV messages prior to advertising capability for
   this message, it MUST discard these messages and not reply to them.
   In this case, the PE SHOULD increment an error counter and optionally
   issue a system and/or SNMP notification to indicate to the system
   administrator that this condition exists.

   When LDP is used as the PW signaling protocol the requesting PE
   indicates its configured VCCV capability or capabilities to the
   remote PE by including the VCCV parameter with appropriate options



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   indicating which control channel types it supports in the VCCV
   interface parameter sub-TLV field of the PW ID FEC TLV (FEC 128) or
   in the interface parameter sub-TLV of the Genralized PW ID FEC TLV
   (FEC 129). The requesting PE MAY indicate that it supports
   multiple control channel options, and in doing so agrees to support
   any and all indicated types if transmitted to it, but MUST do so
   in accordance with the rules stipulated in Section 5.5.1 (VCCV
   Capability Advertisement Sub-TLV).

   Local policy may direct the PE to support certain OAM capability and
   to indicate it. The absence of the VCCV parameter indicates that no
   OAM functions are supported by the requesting PE, and thus the
   receiving PE MUST NOT send any VCCV control channel traffic to it.
   The reception of a VCCV parameter with no options set MUST be
   ignored as if one is not transmitted at all.

   The receiving PE similarly indicates its supported control channel
   types in the response.  These may or may not be the same as the
   ones that were sent to it.  The sender should examine the set that
   is returned to understand which control channels it may establish
   with the remote peer. Similarly, it MUST NOT send control channel
   traffic to the remove PE for which the remote PE has not indicated
   it supports.

   The exception to the rules given in the last two paragraphs above
   is when one side of the PW indicates no support for VCCV while the
   other indicates support for at least one control channel type. This
   case can be realized because the peer advertising 0x00 (None) to
   indicate that it has no desire to accept VCCV request messages
   for policy reasons, or because the functionality is incomplete on
   that device. In the case where it is configured due to policy
   reasons to not accept VCCV requests, it is still free to generate
   them to its peer if it received a capability advertisement
   from its peer advertising such capability. In this case, based on
   the rules already stated, it is allowed to generate VCCV request
   messages to which the peer will reply (as it has advertised the
   capability to accept VCCV messages of that type). However, the
   peer will not generate requests to it, as it has advertised no
   capabilities as stated earlier.


5.5.1 VCCV Capability Advertisement LDP Sub-TLV

   [RFC4447] defines an Interface Parameter Sub-TLV in the LDP PW ID
   FEC (FEC 128) and an Interface Parameters TLV in the LDP Generalized
   PW ID FEC (FEC 129) to signal different capabilities for specific
   PWs. An optional sub-TLV parameter is defined to indicate the
   capability of supporting none, one or more control channel types



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   for VCCV. This is the VCCV parameter field. If FEC 128 is used the
   VCCV parameter field is carried in the Interface Parameter sub-TLV.
   field If FEC 129 is used it is carried as an Interface Parameter
   sub-TLV in the Interface Parameters TLV.

   The VCCV parameter ID is defined as follows in [RFC4446]:

        Parameter ID   Length     Description
          0x0c           4           VCCV

   The format of the VCCV parameter field is as follows:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      0x0c     |       0x04    |   CC Types    |   CV Types    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Control Channel (CC Types) type field defines a bitmask used to
   indicate the type of control channel(s) (i.e.: none, one or more)
   that a router is capable of receiving control channel traffic on.
   If more than one control channel is specified, the router agrees
   to accept control traffic over either control channel; however,
   see the rules specified in Section 7 for more details.
   If none of the types are supported, a CC Type Indicator of 0x00
   SHOULD be transmitted to indicate this to the peer. However,
   if no capability is signaled, then the PE MUST assume that its
   peer is incapable of receiving any of the VCCV CC Types and
   MUST NOT send any OAM control channel traffic to it. Note that
   the CC and CV types definitions are consistent regardless of
   the PW's transport or access circuit type. The CC and CV values
   are defined in Section 4.

6. VCCV Control Channel for L2TPv3/IP PSN

   When L2TPv3 is used to setup a PW over an IP PSN, VCCV packets are
   carried over the L2TPv3 session as defined in this section.  L2TPv3
   provides a "Hello" keepalive mechanism for the L2TPv3 control plane
   that operates in-band over IP or UDP (see Section 4.4 of [RFC3931]).
   This built-in Hello facility provides dead peer and path detection
   only for the group of sessions associated with the L2TP Control
   Connection. VCCV, however, allows individual L2TP sessions to be
   tested. This provides a more granular mechanism which can be used to
   troubleshoot potential problems within the dataplane of L2TP
   endpoints themselves, or to provide additional connection status of
   individual Pseudowires.

   The capability of which control channel type (CC Type) to use is



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   advertised by a PE to indicate which of the potentially various
   control channel types are supported. Once the receiving PE
   has chosen a mode to use, it MUST continue using this mode
   until such time as the PW is re-signaled. Thus, if a new CC
   type is desired, the PW must be torn-down and re-established.

   In order to carry VCCV messages within an L2TPv3 session data packet,
   the PW MUST be established such that an L2-Specific Sublayer (L2SS)
   that defines the V-bit is present.  This document defines the V-bit
   for the Default L2-Specific Sublayer [RFC3931] and the ATM-Specific
   Sublayer [RFC4454] using the Bit 0 position (see Section 8.2.2 and
   Section 8.2.3).  The L2-Specific Sublayer presence and type (either
   the Default or a PW-Specific L2SS) is signaled via the L2-Specific
   Sublayer AVP, Attribute Type 69, as defined in [RFC3931].  The V-bit
   within the L2-Specific Sublayer is used to identify that a VCCV
   message follows, and when the V-bit is set the L2SS has the following
   format:

     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
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
    |1|0 0 0|Version|   Reserved    |         Channel Type          |
    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

          L2-Specific Sublayer Format when the V-bit (bit 0) is set

   The VCCV messages are distinguished from user data by the V-bit.  The
   V-bit is set to 1, indicating that a VCCV session message follows.
   The next three bits MUST be set to 0 when sending and ignored upon
   receipt. The remaining fields comprising 28 bits (i.e., Version,
   Reserved and Channel Type) follow the same definition, format and
   number registry from Section 5 of [RFC4385].

   Depending on the CV Type in use, the Channel Type can indicate IPv4,
   IPv6 (see [RFC4385]) or BFD (see Section 8.1.3) as VCCV payload
   directly following the L2SS. For CV Types of 0x01, 0x04 and 0x08,
   the Channel Type can indicate IPv4 (0x21) or IPv6 (0x56); for CV
   Types of 0x10 and 0x20, the Channel Type indicates BFD Without
   IP/UDP Header (0x07).


6.1. L2TPv3 VCCV Message

   The VCCV message over L2TPv3 directly follows the L2-Specific
   Sublayer with the V-bit set.  It could either contain an ICMP Echo
   packet as described in Section 6.1.1, or a BFD packet as described in
   Section 6.1.2.




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6.1.1. L2TPv3 VCCV using ICMP Ping

   When this connectivity verification mode is used, an ICMP Echo packet
   [RFC792] achieves connectivity verification.  The ICMP Ping packet
   directly follows the L2SS with the V-bit set.  In the ICMP Echo
   request, the IP Header fields MUST have the following values: the
   destination IP address is set to the remote LCCE's IP address for the
   tunnel endpoint, the source IP address is set to the local LCCE's IP
   address for the tunnel endpoint, and the TTL is set to 1.


6.1.2. L2TPv3 VCCV using BFD

   The L2TPv3 Session ID provides the context to demultiplex the first
   BFD control packet. See Section 4.1 and Section 4.1.1 for additional
   details on BFD usage and BFD encapsulation.

6.2. L2TPv3 VCCV Capability Indication

   A new optional AVP is defined in Section 6.2.1 to indicate the
   VCCV capabilities during session establishment.  An LCCE MUST signal
   its desire to use connectivity verification for a particular L2TPv3
   session and its VCCV capabilities using the VCCV Capability AVP.


6.2.1. L2TPv3 VCCV Capability AVP

   The "VCCV Capability AVP", Attribute type AVP-TBD, specifies the VCCV
   capabilities as a pair of bitflags for the Control Channel (CC) and
   Connectifity Verification (CV) Types.  This AVP is exchanged during
   session establishment (in ICRQ, ICRP, OCRQ or OCRP messages). The
   value field has the following format:

   VCCV Capability AVP (ICRQ, ICRP, OCRQ, OCRP)

       0                   1
       0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      |   CC Types    |   CV Types    |
      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   CC Types:

      The Control Channel (CC) Types field defines a bitmask used to
      indicate the type of control channel(s) that may be used to
      receive OAM traffic on for the given Session.  The router agrees
      to accept VCCV traffic at any time over any of the signaled VCCV



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      control channel types.  CC Type values are defined in Section 4.
      Although there is only one value defined in this document, the CC
      Types field is included for forward compatibility should further
      CC Types need to be defined in the future.

      A CC Type of 0x01 may only be requested when there is an
      L2-Specific Sublayer that defines the V-bit present. If a CC Type
      of 0x01 is requested without requesting an L2-Specific Sublayer
      AVP with an L2SS type that defines the V-bit, the session MUST be
      disconnected with a CDN message.

      If no CC Type is supported, a CC Type Indicator of 0x00 SHOULD be
      sent.

   CV Types:

      The Connectifity Verification (CV) Types field defines a bitmask
      used to indicate the specific type or types (i.e.: none, one or
      more) of control packets that may be sent on the specified VCCV
      control channel. CV Type values are defined in Section 4.


   If no VCCV Capability AVP is signaled, then the LCCE MUST assume that
   the peer is incapable of receiving VCCV and MUST NOT send any OAM
   control channel traffic to it.

   All L2TP AVPs have an M (Mandatory) bit, H (Hidden) bit, Length, and
   Vendor ID. The Vendor ID for the VCCV Capability AVP MUST be 0,
   indicating that this is an IETF-defined AVP.  This AVP MAY be hidden
   (the H bit MAY be 0 or 1).  The M bit for this AVP SHOULD be set to
   0.  The Length (before hiding) of this AVP is 8.


6.3. L2TPv3 VCCV Operation

   An LCCE sends VCCV messages on an L2TPv3 signaled Pseudowire for
   fault detection and diagnostic of the L2TPv3 session.  The VCCV
   message travels inband with the Session and follows the exact same
   path as the user data for the session, because the IP header and
   L2TPv3 Session header are identical.  The egress LCCE of the L2TPv3
   session intercepts and processes the VCCV message, and verifies the
   signaling and forwarding state of the Pseudowire on reception of the
   VCCV message. Any faults detected can be signaled in the VCCV
   response. It is to be noted that the VCCV mechanism for L2TPv3 is
   primarily targeted at verifying the Pseudowire forwarding and
   signaling state at the egress LCCE. It also helps when L2TPv3 Control
   Connection and Session paths are not identical.




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   An LCCE MUST NOT send VCCV packets on an L2TPv3 session unless it has
   received VCCV capability by means of the VCCV Capability AVP from the
   remote end.  If an LCCE receives VCCV packets and its not VCCV
   capable or it has not sent VCCV capability indication to the remote
   end, it MUST discard these messages.  It should also increment an
   error counter. In this case the LCCE MAY optionally issue a system
   and/or SNMP notification.

   Additionally, because BFD is bidirectional in nature, when using BFD
   as the connectivity verification type, an LCCE must send VCCV packets
   on an L2TPv3 session only if it has signaled VCCV capability with a
   BFD CV Type to the remote end and received VCCV capability with a
   matching BFD CV Type from the remote end.


7. Capability Advertisement Preference Order

   When a PE receives a VCCV capability advertisement,
   the advertisement may potentially contain more than one CC or
   CV Type. In this case, it MUST use the following rules when
   choosing which CC or CV type to use. It may only choose one mode
   based on the rules stipulated in sections 4 and 5 above. In
   particular, once a valid CC Type is used by a PE (traffic
   sent using that encapsulation), the PE MUST NOT send any
   traffic down another CC Type encapsulation.

   CC Types:

   0x01 - PWE3 control word with 0001b as first nibble
   0x02 - MPLS Router Alert Label
   0x04 - MPLS PW Demultiplexor Label TTL = 1

   For cases were multiple CC Types are advertised,
   the following precedence rules apply when choosing:

   0x01 - PWE3 control word with 0001b as first nibble
   0x04 - MPLS PW Demultiplexor Label TTL = 1
   0x02 - MPLS Router Alert Label

   The following precedence rules are used for choosing
   CV Type to use:

   0x02 -  LSP Ping.
   0x04 -  BFD for PW Fault Detection only.
   0x01 -  ICMP Ping.
   0x08 -  BFD for PW Fault Detection and AC/PW Fault.
           Status Signaling.
   0x10 -  BFD for PW Fault Detection Only. Carrying BFD payload



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           without IP headers.
   0x20 -  BFD for PW Fault Detection and AC/PW Fault
           Status Signaling. Carrying BFD payload without IP headers.


8. IANA Considerations

8.1. VCCV Parameter ID

   The VCCC parameter ID codepoint is defined in [RFC4446]. IANA
   is requested to create and maintain registries for the CC Types
   and CV Types (bitmasks in the VCCV Parameter ID). The CC Type and
   CV Type new registries (see Section 8.1.1 and 8.1.2 respectively)
   are to be created in the Pseudo Wires Name Spaces. The allocations
   must be done using the "Expert Review" policy defined in RFC2434.

8.1.1. Control Channel Types (CC Types)

   IANA is requested to set up a registry of "VCCV Control Channel
   Types". These are 8 bitfield values. CC Type values 0x01, 0x02, and
   0x04 are specified in Section 4 of this document. The remaining
   bitfield values (0x08, 0x10, 0x20, 0x40 and 0x80) are to be assigned
   by IANA using the "Expert Review" policy defined in [RFC2434].
   A VCCV Control Channel Type description is required for any
   assignment from this registry.  A document reference should also be
   provided.

       Bit 0 (0x01) - Type 1: PWE3 control word with 0001b
                      as first nibble as defined in [RFC4385].
       Bit 1 (0x02) - Type 2: MPLS Router Alert Label.
       Bit 2 (0x04) - Type 3: MPLS PW Demultiplexor Label
                      TTL = 1 (Type 3).
       Bit 3 (0x08) - Reserved
       Bit 4 (0x10) - Reserved
       Bit 5 (0x20) - Reserved
       Bit 6 (0x40) - Reserved
       Bit 7 (0x80) - Reserved

8.1.2. Connectivity Verification Types (CV Types)

   IANA is requested to set up a registry of "VCCV Control Verification
   Types".  These are 8 bitfield values. CV Type values 0x01, 0x02, 0x04
   0x08, 0x10 and 0x20 are specified in Section 4 of this document. The
   remaining bitfield values (0x40 and 0x80) are to be assigned by IANA
   using the "Expert Review" policy defined in [RFC2434]. A VCCV Control
   Verification Type description is required for any assignment from
   this registry.  A document reference should also be provided.




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       Bit 0 (0x01) - ICMP Ping.
       Bit 1 (0x02) - LSP Ping.
       Bit 2 (0x04) - BFD for PW Fault Detection Only.
       Bit 3 (0x08) - BFD for PW Fault Detection and AC/PW Fault
                      Status Signaling.
       Bit 4 (0x10) - BFD for PW Fault Detection Only. Carrying
                      BFD payload without IP headers.
       Bit 5 (0x20) - BFD for PW Fault Detection and AC/PW Fault
                      Status Signaling. Carrying BFD payload
                      without IP headers.
       Bit 6 (0x40) - Reserved
       Bit 7 (0x80) - Reserved

8.1.3  Channel Type

   The Channel Types used by VCCV as defined above in sections
   4.1, 4.2 and 4.3 rely on previously allocated numbers
   from the Pseudowire Associated Channel Types Registry
   [RFC4385] in the Pseudo Wires Name Spaces. In particular,
   0x21 (Internet Protocol version 4) MUST be used whenever an
   IPv4 payload follows the Pseudowire control word, or 0x57 MUST
   be used when an IPv6 payload follows the Pseudowire control word.

   In cases where raw BFD follows the Pseudowire control word
   (i.e.: the IP/UDP encapsulation as specified in [BFD]
   will not be present), a new Pseudowire Associated Channel
   Types Registry [RFC4385] entry of 0x07 is used. IANA is
   requested to reserve a new Channel Types value as follows:

  Value (in hex)  Protocol Name                    Reference
  --------------  -------------------------------  ---------

  0007            BFD Without IP/UDP Header        [This document]


8.2. L2TPv3 Assignments

   Sections 8.2.1 through 8.2.3 are registrations of new L2TP values for
   name spaces already managed by IANA.  Section 8.2.4 requests a new
   registry to be added to the existing L2TP registry, and be maintained
   by IANA accordingly.

8.2.1. Control Message Attribute Value Pairs (AVPs)

   An additiona AVP Attribute is specified in Section 6.2.1.  It is
   required to be defined by IANA as described in Section 2.2 of
   [RFC3438].




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      Attribute
      Type        Description
      ---------   ----------------------------------
      AVP-TBD     VCCV Capability AVP

8.2.2. Default L2-Specific Sublayer bits

   The Default L2-Specific Sublayer contains 8 bits in the low-order
   portion of the header.  This document defines one reserved bits in
   the Default L2-Specific Sublayer in Section 6, which may be assigned
   by IETF Consensus [RFC2434]. It is required to be assigned by IANA.

      Default L2-Specific Sublayer bits - per [RFC3931]
      ---------------------------------
      Bit 0 - V (VCCV) bit

8.2.3. ATM-Specific Sublayer bits

   The ATM-Specific Sublayer contains 8 bits in the low-order portion of
   the header.  This document defines one reserved bits in the ATM-
   Specific Sublayer in Section 6, which may be assigned by IETF
   Consensus [RFC2434]. It is required to be assigned by IANA.

      ATM-Specific Sublayer bits - per [RFC4454]
      --------------------------
      Bit 0 - V (VCCV) bit

8.2.4. VCCV Capability AVP Values

   This is a new registry for IANA to maintain.

   IANA is requested to maintain a registry for the CC Types and CV
   Types bitmasks in the VCCV Capability AVP, defined in Section 6.2.1.
   The allocations must be done using the "Expert Review" policy defined
   in [RFC2434].  A VCCV CC or CV Type description is required for any
   assignment from this registry.  A document reference should also be
   provided.

   IANA is requested to reserve the following bits in this registry:

      VCCV Capability AVP (Attribute Type AVP-TBD) Values
      ---------------------------------------------------

      Control Channel (CC) Types

         Bit 0 (0x01) - L2-Specific Sublayer with V-bit set.
         Bit 1 (0x02) - Reserved
         Bit 2 (0x04) - Reserved



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         Bit 3 (0x08) - Reserved
         Bit 4 (0x10) - Reserved
         Bit 5 (0x20) - Reserved
         Bit 6 (0x40) - Reserved
         Bit 7 (0x80) - Reserved

      Connectifity Verification (CV) Types

         Bit 0 (0x01) - ICMP Ping
         Bit 1 (0x02) - Reserved
         Bit 2 (0x04) - BFD for PW Fault Detection Only.
         Bit 3 (0x08) - BFD for PW Fault Detection and AC/PW Fault
                        Status Signaling.
         Bit 4 (0x10) - BFD for PW Fault Detection Only. Carrying
                        BFD payload without IP headers.
         Bit 5 (0x20) - BFD for PW Fault Detection and AC/PW Fault
                        Status Signaling. Carrying BFD payload
                        without IP headers.
         Bit 6 (0x40) - Reserved
         Bit 7 (0x80) - Reserved


9. Security Considerations

   Routers that implement the mechanism described herein are subject to
   to additional denial-of-service attacks as follows:

     An intruder may impersonate an LDP peer in order to
     force a failure and reconnection of the TCP connection.
     Please see the Security Considerations section of
     [RFC3036] details.

     An intruder could intercept or inject VCCV packets effectively
     providing false positives or false negatives.

     An intruder could deliberately flood a peer router with VCCV
     messages to either obtain services without authorization or to
     deny services to others.

     A misconfigured or misbehaving device could inadvertantly flood
     a peer router with VCCV messages which could result in a denial
     of services. In particular, if a router is either implicitly or
     explicitly indicated that it cannot support one or all of the
     types of VCCV, but is sent those messages in sufficient quantity,
     could result in a denial of service.

   All of attacks above which concern the L2TPv3 or LDP control planes
   may be countered by use of a control message authentication scheme



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   between LDP or L2TPv3 peers, such as the MD5-based scheme outlined in
   [RFC3036] or the MD5 or SHA-1 based schemes described in [RFC3931] to
   provide mutual peer authentication and individual control message
   integrity and authenticity checking (see Section 8.1 of [RFC3931]).
   Implementation of IP source address filters may also aid in deterring
   these types of attacks.

   VCCV message throttling mechanisms should be employed, especially in
   distributed implementations which have a centralized control plane
   processor with various line cards attached by some data path. In
   these architectures VCCV messages may be processed on the central
   processor after being forwarded there by the receiving line card. In
   this case, the path between the line card and the control processor
   may become saturated if appropriate VCCV traffic throttling is not
   employed, which could lead to a denial of service.  Such filtering is
   also useful for preventing the processing of unwanted VCCV messages,
   such as those which are sent on unwanted (and perhaps unadvertised)
   control channel types or VCCV types.

   VCCV spoofing requires MPLS PW label spoofing and spoofing the PSN
   tunnel header. As far as the PW label is concerned the same consider-
   ations as specified in [RFC3031] apply. If the PSN is a MPLS tunnel,
   PSN tunnel label spoofing is also required. For L2TPv3, data packet
   spoofing considerations are outlined in Section 8.2 of [RFC3931].
   While the L2TPv3 Session ID provides traffic separation, the optional
   Cookie provides additional protection to thwarts spoofing attacks. To
   maximize protection against a variety of dataplane attacks, a 64-bit
   cookie can be used. L2TPv3 can also be run over IPsec as detailed in
   Section 4.1.3 of [RFC3931].

10. Acknowledgements

   The authors would like to thank Hari Rakotoranto, Michel Khouderchah,
   Bertrand Duvivier, Vanson Lim, Chris Metz, W. Mark Townsley, Eric
   Rosen, Dan Tappan, Danny McPherson and Luca Martini for their
   valuable comments and suggestions.


11. References

11.1. Normative References

   [RFC792]   Postel, J. "Internet Control Message Protocol,
              RFC792, September 1981.

   [RFC2119]  "Key words for use in RFCs to Indicate Requirement
              Levels.", Bradner, March 1997




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   [RFC3031]  Rosen, E., Viswanathan, A., and R. Callon,
              "Multiprotocol Label Switching Architecture", RFC
              3031, January 2001.

   [RFC3032]  Rosen, E., Rehter, Y., Tappan, D., Farinacci, D.,
              Fedorkow, G., Li, T. and A. Conta, "MPLS Label
              Stack Encoding", RFC3032, January 2001.

   [RFC3036]  Andersson, L., Doolan, P., Feldman, N., Fredette, A.
              and B. Thomas, "Label Distribution Protocol", RFC
              3036, January 2001.

   [RFC3931]  J. Lau, M. Townsley, I. Goyret, "Layer Two Tunneling
              Protocol - Version 3 (L2TPv3)", RFC3931, March 2005.

   [RFC4385]  Bryant, S., Martini, L., McPherson, D.,
              "Pseudowire Emulation Edge-to-Edge (PWE3)
              Control Word for Use over an MPLS PSN",
              RFC4385, February 2006.

   [RFC4446]  Martini, L., "IANA Allocations for
              Pseudo Wire Edge to Edge Emulation (PWE3)",
              RFC4446, April 2006.

   [RFC4447]  Martini, L., Rosen, E., El-Aawar, N., Smith, T.,
              "Pseudowire Setup and Maintenance
              Using the Label Distribution Protocol (LDP)",
              RFC4447, April 2006.

   [RFC4379]  Kompella, K., G. Swallow, " Detecting Multi-Protocol
              Label Switched (MPLS) Data Plane Failures",
              RFC4379, February 2006.

   [BFD]      Katz, D., Ward, D., Bidirectional Forwarding
              Detection", draft-ietf-bfd-05.txt, June 2006.

11.2. Informative References

   [RFC4377]     Nadeau, T., Swallow, G., Allan., D.,
                 "Operations and Management (OAM) Requirements
                 for Multi-Protocol Label Switched (MPLS) Networks"
                 RFC4377, February 2006.

   [RFC3985]     Bryant, S., Pate, P., "Pseudo Wire Emulation
                 Edge-to-Edge Architecture", RFC 3985, March 2005.

   [RFC3916]     Xiao, X., McPherson, D., Pate, P., "Requirements for
                 Pseudo Wire Emulation Edge to-Edge (PWE3)",



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                 RFC3916, September 2004.

   [RFC2434]     Narten, T. and H. Alvestrand.,  "Guidelines for Writing
                 an IANA Considerations Section in RFCs", BCP 26, RFC
                 2434, October 1998.

   [OAM-MAP]     T. Nadeau, et. al, "Pseudo Wire (PW) OAM Message Map-
                 ping", draft-ietf-pwe3-oam-msg-map-03.txt,
                 September 2005

   [RFC3036]     Andersson, L, et al., "LDP Specification",
                 RFC3036, January 2001.

   [RFC3438]     Townsley, W., "Layer Two Tunneling Protocol (L2TP)
                 Internet Assigned Numbers Authority (IANA)
                 Considerations Update", BCP 68, RFC 3438,
                 December 2002.

   [RFC4448]     Martini, L., Rosen, E., El-Aawar, N., Heron, G.,
                 "Encapsulation Methods for Transport of Ethernet
                 over MPLS Networks", RFC4448, April 2006.

   [RFC4454]     Singh, S., Townsley, M., Pignataro, C.,
                 "Asynchronous Transfer Mode (ATM) over
                 Layer 2 Tunneling Protocol Version 3 (L2TPv3)",
                 RFC4454, March 2006.

   [BFDV4V61HOP] Katz, D. and D. Ward, "BFD for IPv4 and IPv6 (Single
                 Hop)", draft-ietf-bfd-v4v6-1hop-05, June 2006.


12. Editor Information

   Thomas D. Nadeau
   Cisco Systems, Inc.
   300 Beaver Brook Road
   Boxborough, MA 01719
   Email: tnadeau@cisco.com

   Carlos Pignataro
   Cisco Systems, Inc.
   7025 Kit Creek Road
   PO Box 14987
   Research Triangle Park, NC 27709

   EMail: cpignata@cisco.com

   Rahul Aggarwal



PWE3 Working Group             Expires July 2007            [Page 24]
          draft-ietf-pwe3-vccv-12       VCCV       January 4, 2007 




   Juniper Networks
   1194 North Mathilda Ave.
   Sunnyvale, CA 94089
   Email: rahul@juniper.net


13. Contributor Information

   George Swallow
   Cisco Systems, Inc.
   300 Beaver Brook Road
   Boxborough, MA 01719
   Email: swallow@cisco.com

   Monique Morrow
   Cisco Systems, Inc.
   Glatt-com
   CH-8301 Glattzentrum
   Switzerland
   Email: mmorrow@cisco.com

   Yuichi Ikejiri
   NTT Communication Corporation
   1-1-6, Uchisaiwai-cho, Chiyoda-ku
   Tokyo 100-8019
   Shinjuku-ku, JAPAN
   Email: y.ikejiri@ntt.com

   Kenji Kumaki
   KDDI Corporation
   KDDI Bldg. 2-3-2,
   Nishishinjuku,
   Tokyo 163-8003,
   JAPAN
   E-mail: ke-kumaki@kddi.com

   Peter B. Busschbach
   Lucent Technologies
   67 Whippany Road
   Whippany, NJ, 07981
   E-mail: busschbach@lucent.com

   Vasile Radoaca
   Nortel Networks
   Billerica, MA, 01803
   Email: vasile@nortelnetworks.com





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15. Full Copyright Statement

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