[Docs] [txt|pdf] [Tracker] [Email] [Diff1] [Diff2] [Nits]

Versions: 00 01 draft-ietf-pwe3-iccp

Network Working Group                                       Luca Martini
Internet Draft                                               Samer Salam
Expiration Date: August 2009                                 Ali Sajassi
Intended status: Standards Track                                   Cisco

Satoru Matsushima                                       Thomas D. Nadeau
Softbank                                                              BT

                                                       February 17, 2009


      Inter-Chassis Communication Protocol for L2VPN PE Redundancy


                     draft-martini-pwe3-iccp-01.txt

Status of this Memo

   This Internet-Draft is submitted to IETF in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF), its areas, and its working groups.  Note that
   other groups may also distribute working documents as Internet-
   Drafts.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   The list of current Internet-Drafts can be accessed at
   http://www.ietf.org/ietf/1id-abstracts.txt.

   The list of Internet-Draft Shadow Directories can be accessed at
   http://www.ietf.org/shadow.html.

   This Internet-Draft will expire on August 17, 2009

Abstract

   This document specifies an inter-chassis communication protocol
   (ICCP) that enables PE redundancy for Virtual Private Wire Service
   (VPWS) and Virtual Private LAN Service (VPLS) applications. The
   protocol runs within a set of two or more PEs, forming a redundancy
   group, for the purpose of synchronizing data amongst the systems. It
   accommodates multi-chassis attachment circuit as well as pseudowire
   redundancy mechanisms.



Martini, et al.                                                 [Page 1]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009




Table of Contents

    1        Specification of Requirements  ........................   3
    2        Acknowledgments  ......................................   4
    3        Introduction  .........................................   4
    4        ICCP Overview  ........................................   4
    4.1      Redundancy Model & Topology  ..........................   4
    4.2      ICCP Interconnect Scenarios  ..........................   6
    4.2.1    Co-located Dedicated Interconnect  ....................   6
    4.2.2    Co-located Shared Interconnect  .......................   7
    4.2.3    Geo-redundant Dedicated Interconnect  .................   7
    4.2.4    Geo-redundant Shared Interconnect  ....................   8
    4.3      ICCP Requirements  ....................................   9
    5        ICC LDP Protocol Extension Specification  .............  10
    5.1      LDP ICCP Capability Advertisement  ....................  11
    5.2      RG Membership Management  .............................  11
    5.3      Application Connection Management  ....................  12
    5.4      Application Versioning  ...............................  13
    5.5      Application Data Transfer  ............................  14
    5.6      Dedicated Redundancy Group LDP session  ...............  14
    6        ICCP PE Node Failure Detection Mechanism  .............  14
    7        ICCP Message Formats  .................................  15
    7.1      Encoding ICC into LDP Messages   ......................  15
    7.1.1    ICC Header  ...........................................  16
    7.1.2    Message Encoding  .....................................  17
    7.2      RG Connect Message  ...................................  19
    7.2.1    Sender Name TLV  ......................................  19
    7.3      RG Disconnect Message  ................................  20
    7.4      RG Notification Message  ..............................  23
    7.4.1    Notification Message TLVs  ............................  23
    7.5      RG Application Data Message  ..........................  26
    8        Application TLVs  .....................................  27
    8.1      Pseudowire Redundancy (PW-RED) Application TLVs  ......  27
    8.1.1    PW-RED Connect TLV  ...................................  27
    8.1.2    PW-RED Disconnect TLV  ................................  28
    8.1.3    PW-RED Config TLV  ....................................  29
    8.1.4    Service Name TLV  .....................................  29
    8.1.5    PW ID TLV  ............................................  29
    8.1.6    Generalized PW ID TLV  ................................  30
    8.2      Multi-chassis LACP (mLACP) Application TLVs  ..........  31
    8.2.1    mLACP Connect TLV  ....................................  32
    8.2.2    mLACP Disconnect TLV  .................................  33
    8.2.3    mLACP System Config TLV  ..............................  33
    8.2.4    mLACP Port Config TLV  ................................  35
    8.2.5    mLACP Change Port Priority TLV  .......................  36
    8.2.6    mLACP Port State TLV  .................................  37



Martini, et al.                                                 [Page 2]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


    9        LDP Capability Negotiation  ...........................  40
   10        Client Applications  ..................................  41
   10.1      Pseudowire Redundancy Application Procedures  .........  41
   10.1.1    Initial Setup  ........................................  41
   10.1.2    Pseudowire Configuration  .............................  41
   10.1.3    Pseudowire Status Synchronization  ....................  42
   10.1.4    PE Node Failure  ......................................  42
   10.2      Attachment Circuit Redundancy Application Procedures  .  42
   10.2.1    Common AC Procedures  .................................  42
   10.2.2    AC Failure  ...........................................  43
   10.2.3    PE Node Failure  ......................................  43
   10.2.4    PE Isolation  .........................................  43
   10.2.5    ATM AC Procedures  ....................................  43
   10.2.6    Frame Relay AC Procedures  ............................  43
   10.2.7    Ethernet AC Procedures  ...............................  43
   10.2.8    Multi-chassis LACP (mLACP) Application Procedures  ....  43
   10.2.8.1  Initial Setup  ........................................  44
   10.2.8.2  mLACP Port Configuration  .............................  44
   10.2.8.3  mLACP Port Status Synchronization  ....................  45
   10.2.8.4  Triggering Failover  ..................................  45
   11        Security Considerations  ..............................  45
   12        IANA Considerations  ..................................  46
   12.1      MESSAGE TYPE NAME SPACE  ..............................  46
   12.2      TLV TYPE NAME SPACE  ..................................  46
   12.3      ICC RG Parameter Type Space  ..........................  46
   12.4      STATUS CODE NAME SPACE  ...............................  47
   13        Normative References  .................................  48
   14        Informative References  ...............................  48
   15        Author's Addresses  ...................................  48





1. Specification of Requirements

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119.












Martini, et al.                                                 [Page 3]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


2. Acknowledgments

   The authors wish to acknowledge the important contributions of Dennis
   Cai, Neil McGill and Amir Maleki.


3. Introduction

   Network availability is a critical metric for service providers as it
   has a direct bearing on their profitability. Outages translate not
   only to lost revenue but also to potential penalties mandated by
   contractual agreements with customers running mission-critical
   applications that require tight SLAs. This is true for any carrier
   network, and networks employing Layer2 Virtual Private Network
   (L2VPN) technology are no exception.  Network high-availability can
   be achieved by employing intra and inter-chassis redundancy
   mechanisms. The focus of this document is on the latter. The document
   defines an Inter-Chassis Communication Protocol (ICCP) that allows
   synchronization of state and configuration data between a set of two
   or more PEs forming a Redundancy Group (RG). The protocol supports
   multi-chassis redundancy mechanisms that can be employed on either
   the attachment circuit or pseudowire front.


4. ICCP Overview

4.1. Redundancy Model & Topology

   The focus of this document is on PE node redundancy. It is assumed
   that a set of two or more PE nodes are designated by the operator to
   form a Redundancy Group (RG). Members of a Redundancy Group fall
   under a single administration (e.g. service provider) and employ a
   common redundancy mechanism towards the access (attachment circuits
   or access pseudowires) and/or towards the core (pseudowires) for any
   given service instance. It is possible, however, for members of a RG
   to make use of disparate redundancy mechanisms for disjoint services.
   The PE devices may be offering any type of L2VPN service, i.e. VPWS
   or VPLS. As a matter of fact, the use of ICCP may even be applicable
   for Layer 3 service redundancy, but this is considered to be outside
   the scope of this document.

   The PEs in a RG offer multi-homed connectivity to either individual
   devices (e.g. CE, DSLAM, etc...) or entire networks (e.g. access
   network). Figure 1 below depicts the model.







Martini, et al.                                                 [Page 4]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


                                    +=================+
                                    |                 |
   Mutli-homed         +----+       |  +-----+        |
   Node  ------------> | CE |-------|--| PE1 ||<------|---Pseudowire-->|
                       |    |--+   -|--|     ||<------|---Pseudowire-->|
                       +----+  |  / |  +-----+        |
                               | /  |     ||          |
                               |/   |     || ICCP     |--> Towards Core
              +-------------+  /    |     ||          |
              |             | /|    |  +-----+        |
              |    Access   |/ +----|--| PE2 ||<------|---Pseudowire-->|
              |   Network   |-------|--|     ||<------|---Pseudowire-->|
              |             |       |  +-----+        |
              |             |       |                 |
              +-------------+       |   Redundancy    |
                ^                   |     Group       |
                |                   +=================+
                |
         Multi-homed Network

                 Figure 1: Generic Multi-chassis Redundancy Model


   In the topology of Figure 1, the redundancy mechanism employed
   towards the access node/network can be one of a multitude of
   technologies, e.g. it could be IEEE 802.3ad Link Aggregation Groups
   with Link Aggregation Control Protocol (LACP), or SONET APS. The
   specifics of the mechanism are out of the scope of this document.
   However, it is assumed that the PEs in the RG are required to
   communicate amongst each other in order for the access redundancy
   mechanism to operate correctly. As such, it is required to run an
   inter-chassis communication protocol among the PEs in the RG in order
   to synchronize configuration and/or running state data.

   Furthermore, the presence of the inter-chassis communication channel
   allows simplification of the pseudowire redundancy mechanism. This is
   primarily because it allows the PEs within a RG to run some
   arbitration algorithm to elect which pseudowire(s) should be in
   active or standby mode for a given service instance. The PEs can then
   advertise the outcome of the arbitration to the remote-end PE(s), as
   opposed to having to embed a hand-shake procedure into the pseudowire
   redundancy status communication mechanism, and every other possible
   Layer 2 status communication mechanism.








Martini, et al.                                                 [Page 5]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


4.2. ICCP Interconnect Scenarios

   When referring to 'interconnect' in this section, we are concerned
   with the links or networks over which Inter-Chassis Communication
   Protocol messages are transported, and not normal data traffic
   between PEs. The PEs which are members of a RG may be either
   physically co-located or geo-redundant.  Furthermore, the physical
   interconnect between the PEs over which ICCP is to run may comprise
   of either dedicated back-to-back links or a shared connection through
   the PSN network (e.g., core). This gives rise to a matrix of four
   interconnect scenarios, described next.


4.2.1. Co-located Dedicated Interconnect

   In this scenario, the PEs within a RG are co-located in the same
   physical location (POP, CO). Furthermore, dedicated links provide the
   interconnect for ICCP among the PEs.

           +=================+     +-----------------+
           |CO               |     |                 |
           |  +-----+        |     |                 |
           |  | PE1 |________|_____|                 |
           |  |     |        |     |                 |
           |  +-----+        |     |                 |
           |     ||          |     |                 |
           |     || ICCP     |     |       Core      |
           |     ||          |     |      Network    |
           |  +-----+        |     |                 |
           |  | PE2 |________|_____|                 |
           |  |     |        |     |                 |
           |  +-----+        |     |                 |
           |                 |     |                 |
           +=================+     +-----------------+

   Figure 2: ICCP Co-located PEs Dedicated Interconnect Scenario



   Given that the PEs are connected back-to-back in this case, it is
   possible to rely on Layer 2 redundancy mechanisms to guarantee the
   robustness of the links carrying the ICCP. For example, if the
   interconnect comprises of IEEE 802.3 Ethernet links, it is possible
   to provide redundant interconnect by means of IEEE 802.3ad Link
   Aggregation Groups.






Martini, et al.                                                 [Page 6]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


4.2.2. Co-located Shared Interconnect

   In this scenario, the PEs within a RG are co-located in the same
   physical location (POP, CO). However, unlike the previous scenario,
   there are no dedicated links between the PEs. The interconnect for
   ICCP is provided through the core network to which the PEs are
   connected. Figure 3 depicts this model.

           +=================+     +-----------------+
           |CO               |     |                 |
           |  +-----+        |     |                 |
           |  | PE1 |________|_____|                 |
           |  |     |<=================+             |
           |  +-----+   ICCP |     |  ||             |
           |                 |     |  ||             |
           |                 |     |  ||   Core      |
           |                 |     |  ||  Network    |
           |  +-----+        |     |  ||             |
           |  | PE2 |________|_____|  ||             |
           |  |     |<=================+             |
           |  +-----+        |     |                 |
           |                 |     |                 |
           +=================+     +-----------------+

   Figure 3: ICCP Co-located PEs Shared Interconnect Scenario


   Given that the PEs in the RG are connected over the Packet Switched
   Network (PSN), then PSN Layer mechanisms can be leveraged to ensure
   the resiliency of the interconnect against connectivity failures. For
   example, it is possible to employ RSVP LSPs with Fast ReRoute (FRR)
   and/or end-to-end backup LSPs.


4.2.3. Geo-redundant Dedicated Interconnect

   In this variation, the PEs within a Redundancy Group are located in
   different physical locations to provide geographic redundancy. This
   may be desirable, for example, to protect against natural disasters
   or the like. A dedicated interconnect is provided to link the PEs,
   which is a costly option, especially when considering the possibility
   of providing multiple such links for interconnect robustness. The
   resiliency mechanisms for the interconnect are similar to those
   highlighted in the co-located interconnect counterpart.







Martini, et al.                                                 [Page 7]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


           +=================+     +-----------------+
           |CO 1             |     |                 |
           |  +-----+        |     |                 |
           |  | PE1 |________|_____|                 |
           |  |     |        |     |                 |
           |  +-----+        |     |                 |
           +=====||==========+     |                 |
                 || ICCP           |       Core      |
           +=====||==========+     |      Network    |
           |  +-----+        |     |                 |
           |  | PE2 |________|_____|                 |
           |  |     |        |     |                 |
           |  +-----+        |     |                 |
           |CO 2             |     |                 |
           +=================+     +-----------------+

   Figure 4: ICCP Geo-redundant PEs Dedicated Interconnect Scenario



4.2.4. Geo-redundant Shared Interconnect

   In this scenario, the PEs of a RG are located in different physical
   locations and the interconnect for ICCP is provided over the PSN
   network to which the PEs are connected. This interconnect option is
   more likely to be the one used for geo-redundancy as it is more
   economically appealing compared to the geo-redundant dedicated
   interconnect. The resiliency mechanisms that can be employed to
   guarantee the robustness of the ICCP transport are PSN Layer
   mechanisms as has been described in a previous section.

           +=================+     +-----------------+
           |CO 1             |     |                 |
           |  +-----+        |     |                 |
           |  | PE1 |________|_____|                 |
           |  |     |<=================+             |
           |  +-----+   ICCP |     |  ||             |
           +=================+     |  ||             |
                                   |  ||   Core      |
           +=================+     |  ||  Network    |
           |  +-----+        |     |  ||             |
           |  | PE2 |________|_____|  ||             |
           |  |     |<=================+             |
           |  +-----+        |     |                 |
           |CO 2             |     |                 |
           +=================+     +-----------------+

   Figure 5: ICCP Geo-redundant PEs Shared Interconnect Scenario



Martini, et al.                                                 [Page 8]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


4.3. ICCP Requirements

   The Inter-chassis Communication Protocol should satisfy the following
   requirements:

        -i. Provide a control channel for communication between PEs in
            Redundancy Group (RG). Nodes maybe co-located or remote
            (refer to Interconnect Scenarios section above). It is
            expected that client applications which make use of ICCP
            services will only use this channel to communicate control
            information and not data-traffic. As such the protocol
            should cater for low-bandwidth, low-delay and highly
            reliable message transfer.

       -ii. Accommodate multiple client applications (e.g. multi-chassis
            LACP, PW redundancy, SONET APS, etc...). This implies that
            the messages should be extensible (e.g. TLV-based) and the
            protocol should provide a robust application registration
            and versioning scheme.

      -iii. Provide reliable message transport and in-order delivery
            between nodes in a RG with secure authentication mechanisms
            built into the protocol. The redundancy applications that
            are clients of ICCP expect reliable message transfer, and as
            such will assume that the protocol takes care of flow-
            control and retransmissions. Furthermore, given that the
            applications will rely on ICCP to communicate data used to
            synchronize state-machines on disparate nodes, it is
            critical that ICCP guarantees in-order message delivery.
            Loss of messages or out-of-sequence messages would have
            adverse side-effects to the operation of the client
            applications.

       -iv. Provide a common mechanism to actively monitor the health of
            PEs in a RG.  This mechanism will be used to detect PE node
            failure and inform the client applications. The applications
            require this to trigger failover according to the procedures
            of the employed redundancy protocol on the AC and PW. It is
            desired to achieve sub-second detection of loss of remote
            node (~ 50 - 150 msec) in order to give the client
            applications (redundancy mechanisms) enough reaction time to
            achieve sub-second service restoration time.

        -v. Provide asynchronous event-driven state update, independent
            of periodic messages, for immediate notification of client
            applications' state changes.  In other words, the
            transmission of messages carrying application data should be
            on-demand rather than timer-based to minimize inter-chassis



Martini, et al.                                                 [Page 9]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


            state synchronization delay.

       -vi. Accommodate multi-link and multi-hop interconnect between
            nodes. When the devices within a RG are located in different
            physical locations, the physical interconnect between them
            will comprise of a network rather than a link. As such, ICCP
            should accommodate the case where the interconnect involves
            multiple hops. Furthermore, it is possible to have multiple
            (redundant) paths or interconnects between a given pair of
            devices. This is true for both the co-located and geo-
            redundant scenarios. ICCP should handle this as well.

      -vii. Ensure transport security between devices in a RG. This is
            especially important in the scenario where the members of a
            RG are located in different physical locations and connected
            over a shared (e.g. PSN) network.

     -viii. Must allow operator to statically configure members of RG.
            Auto-discovery may be considered in the future.

       -ix. Allow for flexible RG membership. It is expected that only
            two nodes per an RG will cover most of the redundancy
            applications for common deployments.  However, ICCP should
            not preclude supporting more than two nodes in a RG by
            virtue of design.  Furthermore, it is required to allow a
            single node to be member of multiple RGs simultaneously.


5. ICC LDP Protocol Extension Specification

   To address the requirements identified in the previous section, ICCP
   is modeled to comprise of three layers:

        -i. Application Layer: This provides the interface to the
            various redundancy applications that make use of the
            services of ICCP. ICCP is concerned with defining common
            connection management procedures and the formats of the
            messages exchanged at this layer; however, beyond that, it
            does not impose any restrictions on the procedures or
            state-machines of the clients, as these are deemed
            application-specific and lie outside the scope of ICCP.
            This guarantees implementation inter-operability without
            placing any unnecessary constraints on internal design
            specifics.







Martini, et al.                                                [Page 10]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


       -ii. Inter Chassis Communication (ICC) Layer: This layer
            implements the common set of services which ICCP offers to
            the client applications. It handles protocol versioning, RG
            membership, PE node identification and ICCP connection
            management.

      -iii. Transport Layer: This layer provides the actual ICCP message
            transport. It is responsible for addressing, route
            resolution, flow-control, reliable and in-order message
            delivery, connectivity resiliency/redundancy and finally PE
            node failure detection. The Transport layer may differ
            depending on the Physical Layer of the inter-connect.


5.1. LDP ICCP Capability Advertisement

   When a RG is enabled on a particular PE, the capability of supporting
   ICCP must be advertised to all LDP peers in that RG. This is achieved
   by using the methods in [LDP-CAP] and advertising the ICCP LDP
   capability TLV. If an LDP peer supports the dynamic capability
   advertisement, this can be done by sending a new capability message
   with the S bit set for the ICCP capability TLV when the first RG is
   enabled on the PE. If the peer does not support dynamic capability
   advertisement, then the ICCP TLV MUST be included in the LDP
   initialization procedures in the capability parameter [LDP-CAP].


5.2. RG Membership Management

   ICCP defines a mechanism that enables PE nodes to manage their RG
   membership. When a PE is configured to be a member of a RG, it will
   first advertise the ICCP capability to its peers. Subsequently, the
   PE sends a RG Connect message to the peers that have also advertised
   ICCP capability. The PE then waits for the peers to send their own RG
   Connect messages, if they haven't already. For a given RG, the ICCP
   connection between two devices is considered to be operational only
   when both have sent and received ICCP RG Connect messages for that
   RG.

   If a PE that has sent a particular RG Connect message doesn't receive
   a corresponding RG Connect (or a Notification message with NAK) from
   a destination, it will remain in a state expecting the corresponding
   RG Connect message (or Notification message). The RG will not become
   operational until the corresponding RG Connect Message has been
   received. If a PE that has sent an RG Connect message receives a
   Notification message with a NAK, it will stop attempting to bring up
   the ICCP connection immediately. The PE MUST resume bringing up the
   connection after it receives a RG Connect message from the peer PE



Martini, et al.                                                [Page 11]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


   for the RG in question. This is achieved by responding to the
   incoming RG Connect message with an appropriate RG Connect.

   A device MUST send a NAK for a RG Connect message if at least one of
   the following conditions is satisfied:

        -i. the PE is not a member of the RG;

       -ii. the maximum number of simultaneous ICCP connections that the
            PE can handle is exceeded.

   A PE sends a RG Disconnect message to tear down the ICCP connection
   for a given RG. This is a unilateral operation and doesn't require
   any acknowledgement from the other PEs. Note that the ICCP connection
   for a RG MUST be operational before any client application can make
   use of ICCP services in that RG.


5.3. Application Connection Management

   ICCP provides a common set of procedures by which applications on one
   PE can connect to their counterparts on another PE, for purpose of
   inter-chassis communication in the context of a given RG. The
   prerequisite for establishing an application connection is to have an
   operational ICCP RG connection between the two endpoints. It is
   assumed that the association of applications with RGs is known
   apriori, e.g. by means of device configuration. ICCP then sends an
   Application-specific Connect TLV (carried in RG Connect message), on
   behalf of each client application, to each remote PE within the RG.
   The client may piggyback application-specific information in that
   Connect TLV, which for example can be used to negotiate parameters or
   attributes prior to bringing up the actual application connection.
   The procedures for bringing up the application connection are similar
   to those of the ICCP connection:  An application connection between
   two nodes is up only when both nodes have sent and received RG
   Connect Messages with the proper Application-specific Connect TLVs. A
   PE MUST send a Notification Message to NAK an application connection
   request if one of the following conditions is encountered:

        -i. the application doesn't exist or is not configured for that
            RG;

       -ii. the application connection count exceeds the PE's
            capabilities.

   When a PE receives such a NAK notification, it should stop attempting
   to bring up the application connection until it receives a new
   application connection request from the remote PE. This is done by



Martini, et al.                                                [Page 12]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


   responding to the incoming RG Connect message (carrying an
   Application-specific Connect TLV) with an appropriate RG Connect
   message (carrying a corresponding Application-specific Connect TLV).

   When an application is stopped on a device or it is no longer
   associated with a RG, it should signal ICCP to trigger sending an
   Application-specific Disconnect TLV (in RG Disconnect message). This
   is a unilateral notification to the other PEs within a RG, and as
   such doesn't trigger any response.


5.4. Application Versioning

   During application connection setup time, a given application on one
   PE can negotiate with its counterpart on a peer PE the proper
   application version to use for communication. If no common version is
   agreed upon, then the application connection is not brought up. This
   is achieved through the following simple rules:

     - If an application receives an Application-specific Connect TLV
       with a version that is higher than its own, it MUST send a
       Notification message with a NAK TLV indicating status code
       "Incompatible Protocol Version" and supplying the version that is
       locally supported by the PE.

     - If an application receives an Application-specific Connect TLV
       with a version that is lower than its own, it MAY respond with a
       RG Connect that has an Application-specific Connect TLV using the
       same version that was received. Alternatively, the application
       MAY respond with a Notification message to NAK the request using
       the "Incompatible Protocol Version" code, and supplying the
       version that is supported. The above allows an application to
       operate in either backwards compatible or incompatible modes.

     - If an application receives an Application-specific Connect TLV
       with a version that is equal to its own, then the application
       MUST honor or reject the request based on whether the application
       is configured for the RG in question, and whether or not the
       application connection count has been exceeded.












Martini, et al.                                                [Page 13]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


5.5. Application Data Transfer

   When an application has information to transfer over ICCP it triggers
   the transmission of an Application Data message. ICCP guarantees in-
   order and loss-less delivery of data. An application may NAK a
   message or a set of one or more TLVs within a message by using the
   Notification Message with NAK TLV. Furthermore, an application may
   implement its own ACK mechanism, if deemed required, by defining an
   application-specific TLV to be transported in an Application Data
   message.


5.6. Dedicated Redundancy Group LDP session

   In some ICCP applications there is a requirement to exchange a fairly
   large amount of RG information in a very short period of time. In
   order to better distribute the load in a multiple processor system,
   and to avoid head of line blocking to other LDP appications, it may
   be required to inititate a separate TCP/IP session between the two
   LDP speakers.

   This procedure is OPTIONAL, and does not change the operation of LDP
   or ICCP.

   An LSR that requires a separate LDP session will advertise a separate
   LDP adjacency with a non-zero label space identifier. This will cause
   the remote peer to open a separate LDP session for this label space.
   No labels need be advertised in in this label space , as it is only
   used for a particular , or particular set of ICCP RGs. All relevant
   LDP , and ICCP procedures still apply as described in the relevant
   documents.


6. ICCP PE Node Failure Detection Mechanism

   ICCP provides its client applications a notification when a remote PE
   that is member of the RG fails. This is used by the client
   applications to trigger failover according to the procedures of the
   employed redundancy protocol on the AC and PW. To that end, ICCP does
   not define its own KeepAlive mechanism for purpose of monitoring the
   health of remote PE nodes, but rather reuses existing fault detection
   mechanisms. The following mechanisms may be used by ICCP to detect PE
   node failure:

     - BFD

       Run a BFD session [BFD] between the PEs that are members of a
       given RG, and use that to detect PE node failure. This assumes



Martini, et al.                                                [Page 14]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


       that resiliency mechanisms are in place to protect connectivity
       to the remote PE nodes, and hence loss of BFD periodic messages
       from a given PE node can only mean that the node itself has
       failed.

     - IP Reachability Monitoring

       It is possible for a PE to monitor IP layer connectivity to other
       members of a RG that are participating in IGP/BGP. When
       connectivity to a given PE is lost, the local PE interprets that
       to mean loss of the remote PE node.  This assumes that resiliency
       mechanisms are in place to protect the route to the remote PE
       nodes, and hence loss of IP reachability to a given node can only
       mean that the node itself has failed.

   It is worth noting here that loss of the LDP session with a PE in a
   RG is not a reliable indicator that the remote PE itself is down. It
   is possible, for e.g. that the remote PE encounters a local event
   that leads to resetting the LDP session, while the PE node remains
   operational for purpose of traffic forwarding.


7. ICCP Message Formats

   This section defines the messages exchanged at the Application and
   ICC layers.


7.1. Encoding ICC into LDP Messages

   ICCP requires reliable, in order, state-full message delivery, as
   well as capability negotiation between PEs. The LDP protocol offers
   all these features, and is already in wide use in the applications
   that would also require the ICCP protocol extensions. For these
   reasons, ICCP takes advantage of the already defined LDP protocol
   infrastructure.  [RFC5036] Section 3.5 defines a generic LDP message
   structure. A new set of LDP message types is defined to communicate
   the ICCP information. LDP message types in the range of 0x700 to
   0x7ff will be used for ICCP.

   Message types are allocated by IANA, and requested in the IANA
   section below.









Martini, et al.                                                [Page 15]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


7.1.1. ICC Header

   Every ICCP message comprises of an ICC specific LDP Header followed
   by an ICCP message. The format of the ICC Header 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|   Message Type              |      Message Length           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Message ID                                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type=0x0005 (ICC RG ID)     |           Length=4            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          ICC RG ID                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +                                                               +
   |                     Mandatory Parameters                      |
   ~                                                               ~
   +                                                               +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   +                                                               +
   |                     Optional Parameters                       |
   ~                                                               ~
   +                                                               +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U-bit

       Unknown message bit.  Upon receipt of an unknown message, if U is
       clear (=0), a notification is returned to the message originator;
       if U is set (=1), the unknown message is silently ignored.  The
       following sections which define messages specify a value for the
       U-bit.


     - Message Type

       Identifies the type of the ICCP message, must be in the range of
       0x0700 to 0x07ff.






Martini, et al.                                                [Page 16]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


     - Message Length

       Two octet integer specifying the total length of this message in
       octets, excluding the U-bit, Message Type and Length fields.

     - Message ID

       Four octet value used to identify this message.  Used by the
       sending PE to facilitate identifying RG Notification messages
       that may apply to this message.  A PE sending a RG Notification
       message in response to this message SHOULD include this Message
       ID in the "NAK TLV" of the RG Notification message; see Section
       "RG Notification Message".

     - ICC RG ID

       A TLV of type 0x0005, length 4, containing 4 octects unsigned
       integer designating the Redundancy Group which the sending device
       is member of. RG ID value 0x00000000 is reserved by the protocol.

     - Mandatory Parameters

       Variable length set of required message parameters.  Some
       messages have no required parameters.

       For messages that have required parameters, the required
       parameters MUST appear in the order specified by the individual
       message specifications in the sections that follow.

     - Optional Parameters

       Variable length set of optional message parameters.  Many
       messages have no optional parameters.

       For messages that have optional parameters, the optional
       parameters may appear in any order.


7.1.2. Message Encoding

   The generic format of an ICC parameter is:










Martini, et al.                                                [Page 17]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|       Type                |             Length            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   TLV(s)                                                      |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U-bit

       Unknown TLV bit. Upon receipt of an unknown TLV, if U is clear
       (=0), a notification MUST be returned to the message originator
       and the entire message MUST be ignored; if U is set (=1), the
       unknown TLV MUST be silently ignored and the rest of the message
       processed as if the unknown TLV did not exist. The sections
       following that define TLVs specify a value for the U-bit.

     - F-bit

       Forward unknown TLV bit. This bit applies only when the U-bit is
       set and the LDP message containing the unknown TLV is to be
       forwarded. If F is clear (=0), the unknown TLV is not forwarded
       with the containing message; if F is set (=1), the unknown TLV is
       forwarded with the containing message. The sections following
       that define TLVs specify a value for the F-bit. By setting both
       the U- and F-bits, a TLV can be propagated as opaque data through
       nodes that do not recognize the TLV.

     - Type

       Fourteen bits indicating the parameter type.

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - TLV(s):  A set of 0 or more TLVs, that vary according to the
       message type.










Martini, et al.                                                [Page 18]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


7.2. RG Connect Message

   The RG Connect Message is used to establish ICCP connection in
   addition to individual Application connections between PEs in a RG: a
   RG Connect message with no "Application-specific connect TLVs"
   signals establishment of the base ICCP connection. RG Connect
   messages with appropriate "Application-specific connect TLVs" signal
   the establishment of Application connections, in addition to the base
   ICCP connection (if not already established).  A PE sends a RG
   Connect Message to declare its membership in a Redundancy Group. One
   such message should be sent to each PE that is member of the same RG.
   The set of PEs to which RG Connect Messages should be transmitted is
   known via configuration or an auto-discovery mechanism that is
   outside the scope of this specification. If a device is member of
   multiple RGs, it must send separate RG Connect Messages for each RG
   even if the receiving device(s) happen to be the same.

   The format of the RG Connect Message is as follows:

        -i. ICC header with Message type = "RG Connect Message" (0x0700)
       -ii. "Sender Name TLV"
      -iii. "Application specific connect TLV"

   The currently defined Application-specific connect TLVs are:

     - PW Redundancy Connect TLV

     - mLACP Connect TLV

   The details of these TLVs are discussed in the "Application TLVs"
   section.

   The RG Connect message can contain zero, one or more Application-
   specific connect TLVs. Multiple application connect TLVs can be sent
   in a single message, or multiple messages can be sent containing
   different application connect TLVs, but no application connect TLV
   can be sent more than once.


7.2.1. Sender Name TLV

   A TLV that carries the hostname of the sender encoded in UTF-8. This
   is used primarily for purpose of management of the RG and easing
   network operations.  The specific format is shown below:







Martini, et al.                                                [Page 19]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|           Type            |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Sender Name                                                  |
   +                                             +-+-+-+-+-+-+-+-+-+
   ~                                             ~
   |      ...                                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U=F=0

     - Type set to "ICC sender name"  Parameter type (from ICC parameter
       name space).

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - Sender Name

       Hostname of sending device encoded in UTF-8, and SHOULD NOT
       exceed 80 characters.


7.3. RG Disconnect Message

   The RG Disconnect Message serves dual-purpose: to signal that a
   particular Application connection is being closed within a RG, or
   that the ICCP connection itself is being disconnected because the PE
   wishes to leave the RG.  The format of this message is:

















Martini, et al.                                                [Page 20]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|   Message Type=0x0701       |      Message Length           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Message ID                                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   Type=0x0005 (ICC RG ID)     |           Length=4            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     ICC RG ID                                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Disconnect Code TLV                          |
   +                                                               +
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |           Optional Application-specific Disconnect TLVs       |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |              Optional Parameter TLVs                          |
   +                                                               +
   |                                                               |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U-bit

       U=0

     - Message Type

       The message type for RG Disconnect Message is set to (0x0701)

     - Length

       Length of the TLV in octets excluding the U-bit, Message Type,
       and Message Length fields.

     - Message ID

       Defined in the "ICC Header" section above.

     - ICC RG ID

       Defined in the "ICC Header" section above.






Martini, et al.                                                [Page 21]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


     - Disconnect Code TLV

       The format of this TLV 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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |U|F|         Type=0x0004       |    Length                     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                      ICCP Status Code                         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U,F Bits

       both U and F are set to 0.

     - Type

       set to "Disconnect Code TLV" (0x0004)

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - ICCP Status Code

       A status code that reflects the reason for the disconnect
       message.  Allowed values are "ICCP RG Removed" and "ICCP
       Application Removed from RG".


     - Optional Application-specific Disconnect TLVs

       Zero, one or more Application-specific Disconnect TLVs which are
       defined later in the document. If the RG Disconnect message has a
       status code of "RG Removed", then it should not contain any
       Application-specific Disconnect TLVs, as the sending PE is
       signaling that it has left the RG and, thus, is disconnecting the
       entire ICCP connection, with all associated client application
       connections. If the message has a status code of "Application
       Removed from RG", then it should contain one or more
       Application-specific Disconnect TLVs, as the sending PE is only
       tearing down the connection for the specified applications. Other
       applications, and the base ICCP connection are not to be
       affected.




Martini, et al.                                                [Page 22]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


     - Optional Parameter TLVs

       None are defined for this message in this document.


7.4. RG Notification Message

   A PE sends a RG Notification Message to indicate one of the
   following:  to reject an ICCP connection, to reject an application
   connection, to NAK an entire message or to NAK one or more TLV(s)
   within a message. The Notification message can only be sent to a PE
   that is already part of a RG.

   The format of the Notification Message is:

        -i. ICC header with Message type = "RG Notification Message"
            (0x0702)
       -ii. Notification Message TLVs.

   The currently defined Notification message TLVs are:

        -i. Sender Name TLV
       -ii. NAK TLV.


7.4.1. Notification Message TLVs

   The Sender Name TLV uses the same format as in the RG Connect
   message, and was described above.

   The NAK TLV is defined 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|         Type=0x0002       |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      ICCP Status Code                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Rejected Message ID                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  Optional TLV(s)                              |
   +                                                               +
   |                                                               |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





Martini, et al.                                                [Page 23]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


     - U,F Bits

       both U and F are set to 0.

     - Type

       set to "NAK TLV" (0x0002)

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - ICCP Status Code

       A status code the reflects the reason for the NAK TLV. Allowed
       values are:
            -i. Unknown RG (0x00010001)

                This code is used to reject a new incoming ICCP
                connection for a RG that is not configured on the local
                PE. When this code is used, the Rejected Message ID
                field must contain the message ID of the rejected "RG
                Connect" message.

           -ii. ICCP Connection Count Exceeded (0x00010002)

                This is used to reject a new incoming ICCP connection
                that would cause the local PE's ICCP connection count to
                exceed its capabilities. When this code is used, the
                Rejected Message ID field must contain the message ID of
                the rejected "RG Connect" message.

          -iii. Application Connection Count Exceeded (0x00010003)

                This is used to reject a new incoming application
                connection that would cause the local PE's ICCP
                connection count to exceed its capabilities. When this
                code is used, the Rejected Message ID field must contain
                the message ID of the rejected "RG Connect" message and
                the corresponding Application Connect TLV must be
                included in the "Optional TLV".

           -iv. Application not in RG (0x00010004)

                This is used to reject a new incoming application
                connection when the local PE doesn't support the
                application, or the application is not configured in the



Martini, et al.                                                [Page 24]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


                RG. When this code is used, the Rejected Message ID
                field must contain the message ID of the rejected "RG
                Connect" message and the corresponding Application
                Connect TLV must be included in the "Optional TLV".

            -v. Incompatible Protocol Version (0x00010005)

                This is used to reject a new incoming application
                connection when the local PE has an incompatible version
                of the application. When this code is used, the Rejected
                Message ID field must contain the message ID of the
                rejected "RG Connect" message and the corresponding
                Application Connect TLV must be included in the
                "Optional TLV".

           -vi. Rejected Message (0x00010006)

                This is used to reject a RG Application Data message, or
                one or more TLV(s) within the message.  When this code
                is used, the Rejected Message ID field must contain the
                message ID of the rejected "RG Application Data"
                message.

          -vii. ICCP Administratively Disabled (0x00010007)

                This is used to reject any ICCP messages from a peer
                from which the PE is not allowed to exchenge ICCP
                messages due to local administrative policy.

     - Rejected Message ID

       If non-zero, 32-bit value that identifies the peer message to
       which the NAK TLV refers. If zero, no specific peer message is
       being identified.

     - Optional TLV(s)

       A set of one or more optional TLVs. If the status code is
       "Rejected Message" then this field contains the TLV(s) that were
       rejected. If the entire message is rejected, all its TLVs MUST be
       present in this field; otherwise, the subset of TLVs that were
       rejected MUST be echoed in this field.

       If the status code is "Incompatible Protocol Version" then this
       field contains the "Requested Protocol Version TLV" defined as
       follows:





Martini, et al.                                                [Page 25]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


        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
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |U|F|   Type=0x0003             |    Length                     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |   Connection Reference        |   Requested Version           |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U and F Bits

       Both are set to 0.

     - Type

       set to 0x0003 for "Requested Protocol Version TLV"

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - Connection Reference

       This field is set to the Type field of the Application specific
       Connect TLV that was rejected because of incompatible version.

     - Requested Version

       The version of the application supported by the transmitting
       device. For this version of the protocol it is set to 0x0001.


7.5. RG Application Data Message

   The RG Application Data Message is used to transport application data
   between PEs within a RG. A single message can be used to carry data
   from multiple applications, as long as all these applications are
   part of the same RG. Such multiplexing is possible because the
   transported TLVs are application specific which allows for
   identifying the target application for each TLV at the receiving
   side. The format of the Application Data Message is:

        -i. ICC header with Message type = "RG Application Data Message"
            (0x703)






Martini, et al.                                                [Page 26]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


       -ii. "Application specific TLVs"

   The details of these TLVs are discussed in the "Application TLVs"
   section.


8. Application TLVs

8.1. Pseudowire Redundancy (PW-RED) Application TLVs

   This section discusses the ICCP TLVs for the Pseudowire Redundancy
   application.


8.1.1. PW-RED Connect TLV

   This TLV is included in the RG Connect message to signal the
   establishment of PW-RED application connection.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|   Type=0x0010             |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Protocol Version         |   Optional Sub-TLVs           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
   ~                                                               ~
   |                                                               |
   +                                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             ...                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U and F Bits

       Both are set to 0.

     - Type

       set to 0x0010 for "PW-RED Connect TLV"

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.






Martini, et al.                                                [Page 27]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


     - Protocol Version

       The version of this particular protocol for the purposes of ICCP.
       This is set to 0x0001.

     - Optional Sub-TLVs

       There are no optional Sub-TLVs defined for this version of the
       protocol.


8.1.2. PW-RED Disconnect TLV

   This TLV is used in a RG Disconnect Message to indicate that the
   connection for the PW-RED application is to be terminated.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|   Type=0x0011             |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Optional Sub-TLVs                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U and F Bits

       Both are set to 0.

     - Type

       set to 0x0011 for "PW-RED Disconnect TLV"

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - Optional Sub-TLVs

       There are no optional Sub-TLVs defined for this version of the
       protocol.









Martini, et al.                                                [Page 28]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


8.1.3. PW-RED Config TLV

   The PW-RED Config TLV is used in RG Application Data message and is
   composed of the following TLVs in the following order:
        -i. Service Name TLV
       -ii. PW ID TLV or Generalized PW ID TLV

   In the PW-RED Config TLV the U and F Bits are both are set to 0, and
   the TLV type is set to 0x0012.


8.1.4. Service Name TLV

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|   Type                    |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Service Name                           |
   ~                                                               ~
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U and F Bits

       Both are set to 0.

     - Type

       set to 0x0013 for "Service Name TLV"

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - Service Name

       The name of the L2VPN service instance encoded in UTF-8 format
       and up to 80 character in length.


8.1.5. PW ID TLV

   This TLV is used to communicate the configuration of PWs for VPWS.






Martini, et al.                                                [Page 29]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|   Type                    |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Peer ID                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Group ID                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         PW ID                                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U and F Bits

       Both are set to 0.

     - Type

       set to 0x0014 for "PW ID TLV"

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - Peer ID

       Four octet LDP Router ID of the peer at the far end of the PW.

     - Group ID

       Same as Group ID in [RFC4447] section 5.2.

     - PW ID

       Same as PW ID in [RFC4447] section 5.2.


8.1.6. Generalized PW ID TLV

   This TLV is used to communicate the configuration of PWs for VPLS.









Martini, et al.                                                [Page 30]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|   Type = 0x0015           |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   AGI Type    |    Length     |      Value                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                    AGI  Value (contd.)                        ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   AII Type    |    Length     |      Value                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                   SAII  Value (contd.)                        ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |   AII Type    |    Length     |      Value                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   ~                   TAII Value (contd.)                         ~
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U and F bits

       both set to 0.

     - Type

       set to 0x0015

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - AGI, AII, SAII and TAII

       defined in [RFC4447] section 5.3.2.


8.2. Multi-chassis LACP (mLACP) Application TLVs

   This section discusses the ICCP TLVs for Ethernet attachment circuit
   redundancy using the multi-chassis LACP (mLACP) application.







Martini, et al.                                                [Page 31]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


8.2.1. mLACP Connect TLV

   This TLV is included in the RG Connect message to signal the
   establishment of mLACP application connection.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|   Type=0x0030             |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Protocol Version         |   Optional Sub-TLVs           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
   ~                                                               ~
   |                                                               |
   +                                 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |             ...                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U and F Bits

       Both are set to 0.

     - Type

       set to 0x0030 for "mLACP Connect TLV"

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - Protocol Version

       The version of this particular protocol for the purposes of ICCP.
       This is set to 0x0001.

     - Optional Sub-TLVs

       There are no optional Sub-TLVs defined for this version of the
       protocol.










Martini, et al.                                                [Page 32]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


8.2.2. mLACP Disconnect TLV

   This TLV is used in a RG Disconnect Message to indicate that the
   connection for the mLACP application is to be terminated.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|   Type=0x0031             |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Optional Sub-TLVs                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U and F Bits

       Both are set to 0.

     - Type

       set to 0x0031 for "mLACP Disconnect TLV"

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - Optional Sub-TLVs

       There are no optional Sub-TLVs defined for this version of the
       protocol.


8.2.3. mLACP System Config TLV

   The mLACP System Config TLV is sent in the RG Application Data
   message. This TLV announces the local node's LACP System Parameters
   to the RG peers.













Martini, et al.                                                [Page 33]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|   Type=0x0032             |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         System ID                             |
   +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                               |         System Priority       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Node ID    |
   +-+-+-+-+-+-+-+-+


     - U and F Bits

       Both are set to 0.

     - Type

       set to 0x0032 for "mLACP System Config TLV"

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - System ID

       6 octets field encoding the System ID used by LACP as specified
       in [IEEE-802.3] section 43.3.2.

     - System Priority

       2 octets encoding the  LACP System Priority as defined in [IEEE-
       802.3] section 43.3.2.

     - Node ID

       One octet, LACP node ID. Used to ensure that the LACP Port IDs
       are unique across all devices in a RG. Valid values are in the
       range 0 - 7.










Martini, et al.                                                [Page 34]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


8.2.4. mLACP Port Config TLV

   The mLACP Port Config TLV is sent in the RG Application Data message.
   This TLV is used to notify RG peers about the local configuration
   state of a port.

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|   Type=0x0033             |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Port Number             |    MAC Address                |
   +-------------------------------+                               +
   |                                                               |
   +---------------------------------------------------------------+
   |       Admin Key               |     Port Priority             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Flags     |  IF Name Len  |    Interface Name             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +
   ~                                                               ~
   |                                        ...                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U and F Bits

       Both are set to 0.

     - Type

       set to 0x0033 for "mLACP Port Config TLV"

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - Port Number

       Two octets, LACP Port Number for the corresponding interface as
       specified in [IEEE-802.3] section 43.3.4. When the value of this
       field is 0, it denotes the Aggregator whose key is specified in
       the "Admin Key" field.

     - MAC Address

       Six octets encoding the port MAC address.




Martini, et al.                                                [Page 35]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


     - Admin Key

       Two octets, LACP Admin key for the corresponding interface, as
       specified in [IEEE-802.3] section 43.3.5.

     - Port Priority

       Two octets, LACP port priority for the corresponding interface,
       as specified in [IEEE-802.3] section 43.3.4. This field is valid
       only when the "Flags" field has "Priority Set" asserted.

     - Flags

       Valid values are:

            -i. Synchronized (0x01)

                Indicates that the sender has concluded transmitting all
                member link port configurations for a given Aggregator.
                Also, indicates to the receiving device that its local
                port priorities will not be overridden.

           -ii. Purge Configuration (0x02)

                Indicates that the port is no longer configured for
                mLACP operation.

          -iii. Priority Set (0x04)

                Indicates that the "Port Priority" field is valid.

     - IF Name Len

       One octet, length of the "Interface Name" field in octets.

     - Interface Name

       Interface name encoded in UTF-8 format, up to a maximum of 20
       characters.


8.2.5. mLACP Change Port Priority TLV

   The mLACP Port State TLV is used in RG Application Data message. This
   TLV is used by a device to authoritatively request that a particular
   member of a RG change its port priority.





Martini, et al.                                                [Page 36]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|   Type=0x0034             |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Port Number                |    Port Key                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Port Priority              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


     - U and F Bits

       Both are set to 0.

     - Type

       set to 0x0034 for "mLACP Change Port Priority TLV"

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - Port Number

       2 octets field representing the LACP Port Number as specified in
       [IEEE-802.3] section 43.3.4. When the value of this field is 0,
       it denotes all ports bound to the Aggregator whose key is
       specified in the "Port Key" field.

     - Port Key

       Two octets, LACP port key for the corresponding interface, as
       specified in [IEEE-802.3] section 43.3.5.

     - Port Priority

       Two octets, LACP port priority for the corresponding interface,
       as specified in [IEEE-802.3] section 43.3.4.


8.2.6. mLACP Port State TLV

   The mLACP Port State TLV is used in RG Application Data message. This
   TLV is used by a device to report its LACP port status to other
   members in the RG.




Martini, et al.                                                [Page 37]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F|   Type=0x0035             |    Length                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Partner System ID                        |
   +                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                               |     Partner System Priority   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Partner Port Number       |     Partner Port Priority     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Partner Key             | Partner State |  Actor State  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      Actor Port Number        |           Actor Key           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  Port State   |
   +-+-+-+-+-+-+-+-+


     - U and F Bits

       Both are set to 0.

     - Type

       set to 0x0035 for "mLACP Port State TLV"

     - Length

       Length of the TLV in octets excluding the U-bit, F-bit, Type, and
       Length fields.

     - LACP Partner System ID

       6 octets, the LACP Partner System ID for the corresponding
       interface, encoded as a MAC address as specified in [IEEE-802.3]
       section 43.4.2.2 item r.

     - LACP Partner System Priority

       2 octets field specifying the LACP Partner System Priority as
       specified in [IEEE-802.3] section 43.4.2.2 item q.

     - LACP Partner Port Number

       2 octets encoding the LACP Partner Port Number as specified in
       [IEEE-802.3] section 43.4.2.2 item u.




Martini, et al.                                                [Page 38]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


     - LACP Partner Port Priority

       2 octets field encoding the LACP Partner Port Priority as
       specified in [IEEE-802.3] section 43.4.2.2 item t.

     - LACP Partner Oper Key

       2 octets field representing the LACP Partner Key as defined in
       [IEEE-802.3] section 43.4.2.2 item s.

     - LACP Partner Oper State

       1 octet field encoding the LACP Partner State Variable as defined
       in [IEEE-802.3] section 43.4.2.2 item v.

     - LACP Actor Oper State

       1 octet encoding the LACP Actor's State Variable for the port as
       specified in [IEEE-802.3] section 43.4.2.2 item m.

     - LACP Actor Port Number

       2 octets field representing the LACP Actor Port Number as
       specified in [IEEE-802.3] section 43.3.4. When the value of this
       field is 0, it denotes the Aggregator whose key is specified in
       the "Actor Operational Key" field.

     - LACP Actor Oper Key

       2 octet field encoding the LACP Actor Operational Key as
       specified in [IEEE-802.3] section 43.3.5.

     - Port State

       1 octet encoding the operational state of the port as follows:
           0x00 Up
           0x01 Down
           0x02 Administrative Down
           0x03 Test (e.g. IEEE 802.3ah OAM Intrusive Loopback mode)












Martini, et al.                                                [Page 39]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


9. LDP Capability Negotiation

   As requited in [LDP-CAP] the following TLV is defined to indicate the
   ICCP capability:
    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |U|F| TLV Code Point=0x405      |            Length             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |S| Reserved    |    Reserved   |  VER/Maj      |  Ver/Min      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   where:

     - U-bit

       SHOULD be 1 (ignore if not understood).

     - F-bit

       SHOULD be 0 (don't forward if not understood).

     - TLV Code Point

       The TLV type, which identifies a specific capability. For the
       ICCP code point is requested in the IANA allocation section
       below.

     - S-bit The State Bit indicates whether the sender is advertising
       or withdrawing the ICCP capability. The State bit is used as
       follows:
             1 - The TLV is advertising the capability specified by the
                 TLV Code Point.

             0 - The TLV is withdrawing the capability specified by the
                 TLV Code Point.

     - Ver/Maj

       The major version revision of the ICCP protocol, this document
       specifies 1.0. This field is then set to 1

     - Ver/Min

       The minor version revision of the ICCP protocol, this document
       specifies 1.0. This field is then set to 0




Martini, et al.                                                [Page 40]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


   ICCP capability is advertised to a LDP peer if there is at least one
   RG enabled on the local PE.


10. Client Applications

10.1. Pseudowire Redundancy Application Procedures

   This section defines the procedures for the Pseudowire Redundancy
   (PW-RED) Application.


10.1.1. Initial Setup

   When a RG is configured on a system and multi-chassis pseudowire
   redundancy is enabled in that RG, the PW-RED application should send
   an "RG Connect" message with "PW-RED Connect TLV" to each PE that is
   member of the same RG. When the system receives similar "RG Connect"
   messages from a PE, the two devices can start exchanging "RG
   Application Data" messages for the PW-RED application.

   If a system receives an "RG Connect" message with "PW-RED Connect
   TLV" that has a differing Protocol Version, it must follow the
   procedures outlined in the "Application Versioning" section above.

   When the PW-RED application is disabled on the device, or is
   unconfigured for the RG in question, the system should send an "RG
   Disconnect" message with "PW-RED Disconnect TLV".


10.1.2. Pseudowire Configuration

   A system should advertise its local PW configuration to other PEs
   that are members of the same RG. This allows the PEs to build a view
   of the redundant nodes and pseudowires that are protecting the same
   service instances.  The advertisement should be initiated when the
   PW-RED application connection first comes up, as well as upon any
   subsequent PW configuration change. To that end, the system should
   send "RG Application Data" messages with "PW-RED Config TLV". It is
   possible to send configuration information for multiple PWs in a
   single "RG Application Data" message.

   The "Service Name TLV" is used on the receiving system for the
   purpose of associating PW information advertised by some PE with the
   corresponding AC information received over ICCP from that PE's AC
   redundancy application. The Service Name has a global context in a
   RG, so redundant PWs for the same service on disparate member PEs
   should share the same Service Name, in order to be correlated.



Martini, et al.                                                [Page 41]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


10.1.3. Pseudowire Status Synchronization

   On a given PE, the forwarding status of the PW (Active or Standby) is
   derived from the state of the associated AC(s). This simplifies the
   operation of the multi-chassis redundancy solution (Figure 1) and
   eliminates the possibility of deadlock conditions between the AC and
   PW redundancy mechanisms. The rules by which the PW state is derived
   from the AC state are as follows:

     - VPWS

       For VPWS, there's a single AC per service instance.  If the AC is
       Active, then the PW status should be Active.  If the AC is
       Standby, then the PW status should be Standby.

     - VPLS

       For VPLS, there could be multiple ACs per service instance (i.e.
       VFI).  If AT LEAST ONE AC is Active, then the PW status should be
       Active.  If ALL ACs are Standby, then the PW status should be
       Standby.

   The PW-RED application does not synchronize PW status across chassis,
   per se.  Rather, the AC Redundancy application should synchronize AC
   status between chassis, in order to determine which AC (and
   subsequently which PE) is Active or Standby for a given service. When
   that is determined, each PE will then adjust its local PWs state
   according to the rules described above.


10.1.4. PE Node Failure

   When a PE node detects that a remote PE, that is member of the same
   RG, has gone down, the local PE examines if it has redundant PWs for
   the affected services. If the local PE has the highest priority
   (after the failed PE) then it becomes the active node for the
   services in question, and subsequently activates its associated PWs.


10.2. Attachment Circuit Redundancy Application Procedures

10.2.1. Common AC Procedures

   This section describes generic procedures for AC Redundancy
   applications, independent of the type of the AC (ATM, FR or
   Ethernet).





Martini, et al.                                                [Page 42]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


10.2.2. AC Failure

   When the AC Redundancy mechanism on the Active PE detects a failure
   of the AC, it should send an ICCP Application Data message to inform
   the redundant PEs of the need to take over.  The AC failures can be
   categorized into the following scenarios:

     - Failure of CE interface connecting to PE

     - Failure of CE uplink to PE

     - Failure of PE interface connecting to CE


10.2.3. PE Node Failure

   When a PE node detects that a remote PE, that is member of the same
   RG, has gone down, the local PE examines if it has redundant ACs for
   the affected services. If the local PE has the highest priority
   (after the failed PE) then it becomes the active node for the
   services in question, and subsequently activates its associated ACs.


10.2.4. PE Isolation

   When a PE node detects that is has been isolated from the core
   network (i.e. all core facing interfaces/links are not operational),
   then it should instruct its AC Redundancy mechanism to change the
   status of any active ACs to Standby. The AC Redundancy application
   should then send ICCP Application Data messages in order to trigger
   failover to a standby PE.


10.2.5. ATM AC Procedures

10.2.6. Frame Relay AC Procedures

10.2.7. Ethernet AC Procedures

10.2.8. Multi-chassis LACP (mLACP) Application Procedures

   This section defines the procedures that are specific to the multi-
   chassis LACP (mLACP) application.








Martini, et al.                                                [Page 43]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


10.2.8.1. Initial Setup

   When a RG is configured on a system and mLACP is enabled in that RG,
   the mLACP application should send an "RG Connect" message with "mLACP
   Connect TLV" to each PE that is member of the same RG.  When the
   system receives similar "RG Connect" message from a PE, the two
   devices can start exchanging "RG Application Data" messages for the
   mLACP application.

   If a system receives an "RG Connect" message with "mLACP Connect TLV"
   that has a differing Protocol Version, it must follow the procedures
   outlined in the "Application Versioning" section above.

   After the mLACP application connection has been established, every PE
   must communicate its system level configuration to its peers via the
   use of "mLACP System Config TLV". This allows every PE to discover
   the Node ID and the locally configured System ID and System Priority
   values of its peers. It is necessary for all PEs in a RG to agree
   upon the System ID and System Priority values to be used
   ubiquitously. To achieve this, every PE MUST use the numerically
   lowest value (among RG members) for each of the two parameters. This
   guarantees that the PEs always agree on uniform values, which yield
   the highest System Priority.

   When the mLACP application is disabled on the device, or is
   unconfigured for the RG in question, the system should send an "RG
   Disconnect" message with "mLACP Disconnect TLV".


10.2.8.2. mLACP Port Configuration

   A system must synchronize the configuration of its mLACP operating
   ports with other RG members. To that end, a system must use the "Port
   Config TLVs". An implementation must advertise the configuration of
   Aggregators prior to advertising the configuration of any of their
   associated member links. Aggregators are identified by using the Port
   Number 0 (which is not a valid LACP port number) and the associated
   Key. If the "Priority Set" flag is asserted in such TLV, it indicates
   that the same Port Priority applies to all member links that are
   attached to the Aggregator in question. When the configuration of all
   ports for member links associated with a given Aggregator has been
   sent by a device, it asserts that fact by setting the "Synchronized"
   flag in the last port's "Port Config TLV". This also serves as a cue
   for the receiving system that its local port priorities will not be
   remotely overridden by the sending PE.

   Furthermore, for a given port, an implementation must advertise the
   port's configuration prior to advertising its state (via the "mLACP



Martini, et al.                                                [Page 44]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


   Port State TLV").

   When mLACP is unconfigured on a port, a PE must send a "Port Config
   TLV" with the "Purge Configuration" flag asserted. This allows
   receiving PEs to purge any state maintained for the decommissioned
   port.


10.2.8.3. mLACP Port Status Synchronization

   PEs within a RG need to synchronize their state-machines for proper
   mLACP operation with a multi-homed device. This is achieved by having
   each system advertise its ports' running state in "mLACP Port State
   TLVs". Whenever any port parameter, whether on the Partner (i.e.
   multi-homed device) or the Actor (i.e. PE) side, is changed a system
   MUST transmit an updated "mLACP Port State TLV" for the affected
   port.


10.2.8.4. Triggering Failover

   A PE MAY trigger a failover to a redundant PE within the RG by
   sending an "mLACP Change Port Priority TLV" specifying the affected
   Aggregator and a priority value that causes the remote PE to have a
   higher Port Priority thereby moving to active forwarding state.

   A PE MAY assume active role within the RG by sending an "mLACP Change
   Port Priority TLV" to the currently active PE, specifying the
   affected Aggregator and a port priority value that is less than its
   local port priority for the links associated with that Aggregator.


11. Security Considerations

   The security considerations described in [RFC5036] and [RFC4447] that
   apply to the base LDP specification, and to the PW LDP control
   protocol extensions apply to the capability mechanism described in
   this document.

   The ICCP protocol is not intended to be applicable when the
   redundancy group spans PE in different administrative domains.
   Furthermore, implementations MUST provide a mechanism to select to
   which LDP peers the ICCP capability will be advertised, and from wich
   LDP peers the ICCP messages will be accepted.







Martini, et al.                                                [Page 45]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


12. IANA Considerations

12.1. MESSAGE TYPE NAME SPACE

   This document uses several new LDP message types, IANA already
   maintains a registry of name "MESSAGE TYPE NAME SPACE" defined by
   [RFC5036]. The following values are suggested for assignment:

     Message type  Description
        0x0700     RG Connect Message
        0x0701     RG Disconnect Message
        0x0702     RG Notification Message
        0x0703     RG Application Data Message


12.2. TLV TYPE NAME SPACE

   This document use a new LDP TLV type, IANA already maintains a
   registry of name "TLV TYPE NAME SPACE" defined by [RFC5036]. The
   following value is suggested for assignment:
      TLV Type Description
       0x700       ICCP capability TLV.
       0x701       LDP TCP/IP Port TLV.


12.3. ICC RG Parameter Type Space

   IANA needs to set up a registry of "ICC RG parameter type". These are
   14-bit values. Parameter Type values 1 through 0x000F are specified
   in this document, Parameter Type values 0x0010 through 0x1FFF are to
   be assigned by IANA, using the "Expert Review" policy defined in
   [RFC5226]. Parameter Type values 0x2000 through 0x2FFF, 0x3FFF, and 0
   are to be allocated using the IETF consensus policy defined in
   [RFC5226]. Parameter Type values 0x3000 through 0x3FFE are reserved
   for vendor proprietary extensions and are to be assigned by IANA,
   using the "First Come First Served" policy defined in [RFC5226]. A
   Parameter Type description is required for any assignment from this
   registry. Additionally, for the vendor proprietary extensions range a
   citation of a person or company name is also required. A document
   reference should also be provided.

   Initial ICC RG parameter type space value allocations are specified
   below:

   Parameter Type Description                       Reference
   -------------- --------------------------------- ---------
   0x0001         ICC sender name                   [RFCxxxx]
   0x0002         NAK TLV                           [RFCxxxx]



Martini, et al.                                                [Page 46]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


   0x0003         Requested Protocol Version TLV    [RFCxxxx]
   0x0004         Disconnect Code TLV               [RFCxxxx]
   0x0005         ICC RG ID TLV                     [RFCxxxx]

   0x0010         PW-RED Connect TLV                [RFCxxxx]
   0x0011         PW-RED Disconnect TLV             [RFCxxxx]
   0x0012         PW-RED Config TLV                 [RFCxxxx]
   0x0013         Service Name TLV                  [RFCxxxx]
   0x0014         PW ID TLV                         [RFCxxxx]
   0x0015         Generalized PW ID TLV             [RFCxxxx]

   0x0030         mLACP Connect TLV                 [RFCxxxx]
   0x0031         mLACP Disconnect TLV              [RFCxxxx]
   0x0032         mLACP System Config TLV           [RFCxxxx]
   0x0033         mLACP Port Config TLV             [RFCxxxx]
   0x0034         mLACP Change Port Priority TLV    [RFCxxxx]
   0x0035         mLACP Port State TLV              [RFCxxxx]




12.4. STATUS CODE NAME SPACE

   This document use several new Status codes, IANA already maintains a
   registry of name "STATUS CODE NAME SPACE" defined by [RFC5036]. The
   following values is suggested for assignment:  The "E" column is the
   required setting of the Status Code E-bit.
   Range/Value     E     Description                       Reference
   ------------- -----   ----------------------            ---------
   0x00010001      0     Unknown ICCP RG
   0x00010002      0     ICCP Connection Count Exceeded
   0x00010003      0     ICCP Application Connection
                         Count Exceeded
   0x00010004      0     ICCP Application not in RG
   0x00010005      0     Incompatible ICCP  Protocol Version
   0x00010006      0     ICCP Rejected Message
   0x00010007      0     ICCP Administratively Disabled
   0x00010010      0     ICCP RG Removed
   0x00010011      0     ICCP Application Removed from RG












Martini, et al.                                                [Page 47]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


13. Normative References

   [RFC5036] L. Andersson et al, "LDP Specification", RFC 5036,
        October 2007.

   [LDP-CAP] "LDP Capabilities", draft-ietf-mpls-ldp-capabilities-02.txt
         April 2008, (Work in Progress)

   [RFC4447] "Transport of Layer 2 Frames Over MPLS", Martini, L.,
         et al., rfc4447 April 2006.

   [IEEE-802.3] IEEE Std. 802.3-2005, "Part 3: Carrier Sense Multiple
        Access with Collision Detection (CSMA/CD) Access Method and
        Physical Layer Specifications", IEEE Computer Society, December
        2005.


14. Informative References

   [BFD] D. Katz, D. Ward, "Bidirectional Forwarding Detection",
        draft-ietf-bfd-base-09.txt, February 2009 (Work in Progress)

   [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
        IANA Considerations section in RFCs", BCP 26, RFC 5226, May 2008



15. Author's Addresses


   Luca Martini
   Cisco Systems, Inc.
   9155 East Nichols Avenue, Suite 400
   Englewood, CO, 80112
   e-mail: lmartini@cisco.com


   Samer Salam
   Cisco Systems, Inc.
   595 Burrard Street, Suite 2123
   Vancouver, BC V7X 1J1
   Canada
   e-mail: ssalam@cisco.com








Martini, et al.                                                [Page 48]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009



   Ali Sajassi
   Cisco Systems, Inc.
   170 West Tasman Drive
   San Jose, CA 95134
   e-mail: sajassi@cisco.com


   Satoru Matsushima
   Softbank Telecom
   1-9-1, Higashi-Shinbashi, Minato-ku
   Tokyo 105-7313, JAPAN
   e-mail: satoru.matsushima@tm.softbank.co.jp


   Thomas D. Nadeau
   BT
   BT Centre
   81 Newgate Street
   London,   EC1A 7AJ
   United Kingdom
   e-mail: tom.nadeau@bt.com



Full Copyright Statement

   Copyright (c) 2009 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 in effect on the date of
   publication of this document (http://trustee.ietf.org/licenseinfo).
   Please review these documents carefully, as they describe your rights
   and restrictions with respect to this document.

   This document may contain material from IETF Documents or IETF
   Contributions published or made publicly available before November
   10, 2008. The person(s) controlling the copyright in some of this
   material may not have granted the IETF Trust the right to allow
   modifications of such material outside the IETF Standards Process.
   Without obtaining an adequate license from the person(s) controlling
   the copyright in such materials, this document may not be modified
   outside the IETF Standards Process, and derivative works of it may
   not be created outside the IETF Standards Process, except to format
   it for publication as an RFC or to translate it into languages other
   than English.




Martini, et al.                                                [Page 49]

Internet Draft       draft-martini-pwe3-iccp-01.txt    February 17, 2009


Acknowledgments

   The authors wish to acknowledge the contributions of Satoru
   Matsushima, Wei Luo, Neil Mcgill, Skip Booth, Neil Hart, Michael Hua,
   and Tiberiu Grigoriu.

   Expiration Date: August 2009












































Martini, et al.                                                [Page 50]


Html markup produced by rfcmarkup 1.111, available from https://tools.ietf.org/tools/rfcmarkup/