,Au Nadeau "Thomas D. Nadeau" "BT" PWE3 Working Group Luca Martini Internet Draft Cisco Expires: December 2008 Samer Salam Cisco Satoru Matsushima Ali Sajassi Softbank Cisco June 2008 Inter-Chassis Communication Protocol for L2VPN PE Redundancy draft-martini-pwe3-iccp-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of 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/1id-abstracts.html The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. 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-00.txt June 2008 Table of Contents 1 Specification of Requirements ........................ 3 2 Acknowledgments ...................................... 3 3 Introduction ......................................... 3 4 ICCP Overview ........................................ 4 4.1 Redundancy Model & Topology .......................... 4 4.2 ICCP Interconnect Scenarios .......................... 5 4.2.1 Co-located Dedicated Interconnect .................... 5 4.2.2 Co-located Shared Interconnect ....................... 6 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 ICC capability advertisement ..................... 11 5.2 RG Membership Management ............................. 11 5.3 Application Connection Management .................... 12 5.4 Application Data Transfer ............................ 12 6 ICCP PE Node Failure Detection Mechanism ............. 13 7 ICCP Message Formats ................................. 14 7.1 Encoding ICC into LDP messages ...................... 14 7.1.1 ICC Header ........................................... 14 7.1.2 Message Encoding ..................................... 16 7.2 RG Connect Message ................................... 17 7.2.1 Sender Name TLV ...................................... 18 7.3 RG Disconnect Message ................................ 19 7.4 RG Notification Message .............................. 20 7.4.1 Notification Message TLVs ............................ 21 7.5 RG Application Data Message .......................... 23 7.6 Application TLVs ..................................... 24 7.6.1 Pseudowire Redundancy (PW-RED) Application TLVs ...... 24 7.6.1.1 PW-RED Connect TLV ................................... 24 7.6.1.2 PW-RED Disconnect TLV ................................ 25 7.6.1.3 PW-RED Config TLV .................................... 25 7.6.1.4 Service Name TLV ..................................... 26 7.6.1.5 PW ID TLV ............................................ 26 7.6.1.6 Generalized PW ID TLV ................................ 27 8 LDP Capability Negotiation ........................... 29 9 Client Applications .................................. 30 9.1 Pseudowire Redundancy Application Procedures ......... 30 9.1.1 Initial Setup ........................................ 30 9.1.2 Pseudowire Configuration ............................. 30 9.1.3 Pseudowire Status Synchronization .................... 31 9.1.4 PE Node Failure ...................................... 31 9.2 Attachment Circuit Redundancy Application Procedures . 32 9.2.1 Common AC Procedures ................................. 32 Martini, et al. [Page 2] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 9.2.1.1 AC Failure ........................................... 32 9.2.1.2 PE Node Failure ...................................... 32 9.2.1.3 PE Isolation ......................................... 32 9.2.2 ATM AC Procedures .................................... 32 9.2.3 Frame Relay AC Procedures ............................ 33 9.2.4 Ethernet AC Procedures ............................... 33 10 Security Considerations .............................. 33 11 IANA Considerations .................................. 33 11.1 MESSAGE TYPE NAME SPACE .............................. 33 11.2 TLV TYPE NAME SPACE .................................. 33 11.3 ICC RG Parameter Type Space .......................... 34 11.4 STATUS CODE NAME SPACE ............................... 34 12 Full Copyright Statement ............................. 35 13 Intellectual Property Statement ...................... 35 14 Normative References ................................. 36 15 Informative References ............................... 36 16 Author Information ................................... 36 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. 2. Acknowledgments The authors wish to acknowledge the important contributions of 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 Martini, et al. [Page 3] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 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 an 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 an 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. +=================+ | | 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 Martini, et al. [Page 4] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 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 an 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. 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 an 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 an RG are co-located in the same physical location (POP, CO). Furthermore, dedicated links provide the interconnect for ICCP among the PEs. Martini, et al. [Page 5] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 +=================+ +-----------------+ |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. 4.2.2. Co-located Shared Interconnect In this scenario, the PEs within an 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. Martini, et al. [Page 6] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 +=================+ +-----------------+ |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 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. Because of this particular reason, it is anticipated that this interconnect scenario will not be common for most commercial applications. 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-00.txt June 2008 +=================+ +-----------------+ |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 an 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-00.txt June 2008 4.3. ICCP Requirements The Inter-chassis Communication Protocol should satisfy the following requirements: -i. Provide 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 an 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-00.txt June 2008 state synchronization delay. -vi. Accommodate multi-link and multi-hop interconnect between nodes. When the devices within an 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 an RG. This is especially important in the scenario where the members of an 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 an 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-00.txt June 2008 -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 ICC capability advertisement When an RG is enabled on a particular PE, the capability of supporting ICCP must be advertised to all LDP peers. 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 an RG, it will first advertise the ICCP capability to its peers. Subsequently the PE sends an 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 message, 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 an particular RG Connect message doesn't receive a corresponding RG Connect from a destination it will simply wait indefinitely for the corresponding RG Connect 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. A device MAY send a NAK for an RG Connect message if it is not a member of the RG, or if the maximum number of ICCP connections has been exceeded. Martini, et al. [Page 11] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 A PE sends an 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 an RG should be operational before any client application can make use of ICCP services in that RG. 5.3. Application Connection Management ICCP provides a common procedure 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 Application Connect messages, on behalf of each client application, to each remote PE within the RG. The client may piggyback application-specific information in that Connect message, 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 Application Connect Messages. A PE can send a Notification Message to NAK the Application Connect message if the application doesn't exist or is not configured for that RG, or if the protocol version is not compatible. When a PE receives such a NAK notification, it should stop attempting to bring up the application connection. When an application is stopped on a device or it is no longer associated with an RG, it should signal ICCP to trigger sending an Application Disconnect message. This is a unilateral notification to the other PEs within an RG, and as such doesn't trigger any response. 5.4. 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 an ACK mechanism, if deemed required, by defining an application-specific TLV to be transported in an Application Data message. Martini, et al. [Page 12] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 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: + Loss of LDP Session Loss of the LDP session with a PE in an RG can be used to indicate to the local device that the remote PE is down. This can be, for example, due to the TCP connection being reset. This requires that the transport path for ICCP (and the underlying LDP session) is protected by some Layer 2 or Layer 3 resiliency mechanism. + 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 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 an 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. Martini, et al. [Page 13] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 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 ICC. Message types are allocated by IANA, and requested in the IANA section below. 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: Martini, et al. [Page 14] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 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. + 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 Martini, et al. [Page 15] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 that may apply to this message. A PE sending an 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 Four 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: 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 Martini, et al. [Page 16] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 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. 7.2. RG Connect Message The RG Connect Message is used to establish ICCP connection in addition to individual Application connections between PEs in an RG: an 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 an 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: Martini, et al. [Page 17] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 -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 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: 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. Martini, et al. [Page 18] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 + 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 an RG, or that the ICCP connection itself is being disconnected because the PE wishes to leave the RG. The format of this message is: 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ICC RG ID | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ICCP Status Code | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | 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. Martini, et al. [Page 19] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 + Message ID Defined in the "ICC Header" section above. + ICC RG ID Defined in the "ICC Header" section above. + ICCP Status Code A status code that reflects the reason for the disconnect message. Allowed values are "RG Removed" and "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. + Optional Parameter TLVs None are defined for this message in this document. 7.4. RG Notification Message A PE sends an 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 an RG. The format of the Notification Message is: -i. ICC header with Message type = "RG Notification Message" (0x0702) Martini, et al. [Page 20] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 -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 Rejected TLV(s) | + + | | ~ ~ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + 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: Martini, et al. [Page 21] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 -i. Unknown RG (0x00010001) This code is used to reject a new incoming ICCP connection for an 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 Rejected 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 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 Rejected 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 Rejected TLV". Martini, et al. [Page 22] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 -vi. Rejected Message (0x00010006) This is used to reject an 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 Rejected TLV(s) A set of one or more TLVs that were rejected. If the entire last message received is rejected, no TLVs will be present. However, if only specific TLVs were rejected then those TLVs MUST be echoed in this field. 7.5. RG Application Data Message The RG Application Data Message is used to transport application data between PEs within an 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) -ii. "Application specific TLVs" The details of these TLVs are discussed in the "Application TLVs" section. Martini, et al. [Page 23] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 7.6. Application TLVs 7.6.1. Pseudowire Redundancy (PW-RED) Application TLVs This section discusses the ICCP TLVs for the Pseudowire Redundancy application. 7.6.1.1. 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. + Protocol Version The version of this particular protocol for the purposes of ICCP. This is set to 0x0001. Martini, et al. [Page 24] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 + Optional Sub-TLVs There are no optional Sub-TLVs defined for this version of the protocol. 7.6.1.2. 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. 7.6.1.3. 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. Martini, et al. [Page 25] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 7.6.1.4. 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. 7.6.1.5. PW ID TLV This TLV is used to communicate the configuration of PWs for VPWS. 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 | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Martini, et al. [Page 26] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 + 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 [PWE3-LDP] section 5.2. + PW ID Same as PW ID in [PWE3-LDP] section 5.2. 7.6.1.6. Generalized PW ID TLV This TLV is used to communicate the configuration of PWs for VPLS. Martini, et al. [Page 27] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 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. Martini, et al. [Page 28] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 8. 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 29] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 ICCP capability is advertised to a LDP peer if there is at least one RG enabled on the local PE. 9. Client Applications 9.1. Pseudowire Redundancy Application Procedures This section defines the procedures for the Pseudowire Redundancy (PW-RED) Application. 9.1.1. Initial Setup When an 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 an incompatible Protocol Version, it should reply with "RG Notification" message with "Incompatible Protocol Version" status code and the rejected "PW-RED Connect TLV". When the PW-RED application is disabled on the device, or the RG is de-configured, the system should send an "RG Disconnect" message with "PW-RED Disconnect TLV". 9.1.2. 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 an RG, so redundant PWs for the same service on disparate member PEs Martini, et al. [Page 30] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 should share the same Service Name, in order to be correlated. 9.1.3. 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. 9.1.4. 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. Martini, et al. [Page 31] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 9.2. Attachment Circuit Redundancy Application Procedures 9.2.1. Common AC Procedures This section describes generic procedures for AC Redundancy applications, independent of the type of the AC (ATM, FR or Ethernet). 9.2.1.1. 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 9.2.1.2. 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. 9.2.1.3. 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. 9.2.2. ATM AC Procedures Martini, et al. [Page 32] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 9.2.3. Frame Relay AC Procedures 9.2.4. Ethernet AC Procedures 10. 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. 11. IANA Considerations 11.1. 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 11.2. 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 0x405ICCP capability TLV. Martini, et al. [Page 33] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 11.3. 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 [RFC2434]. Parameter Type values 0x2000 through 0x2FFF, 0x3FFF, and 0 are to be allocated using the IETF consensus policy defined in [RFC2434]. 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 [RFC2434]. 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] 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] 11.4. 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 Martini, et al. [Page 34] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 0x00010007 0 ICCP Administratively Disabled 0x00010010 0 ICCP RG Removed 0x00010011 0 ICCP Application Removed from RG 12. Full Copyright Statement Copyright (C) The IETF Trust (2008). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 13. Intellectual Property Statement The IETF takes no position regarding the validity or scope of any Intellectual Property Rights or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; nor does it represent that it has made any independent effort to identify any such rights. Information on the procedures with respect to rights in RFC documents can be found in BCP 78 and BCP 79. Copies of IPR disclosures made to the IETF Secretariat and any assurances of licenses to be made available, or the result of an attempt made to obtain a general license or permission for the use of such proprietary rights by implementers or users of this specification can be obtained from the IETF on-line IPR repository at http://www.ietf.org/ipr. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf- ipr@ietf.org. Martini, et al. [Page 35] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 14. 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 ) [PWE3-LDP] L. Martini et al, "Pseudowire Setup and Maintenance Using the Label Distribution Protocol", RFC 4447, 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. 15. Informative References none 16. Author Information 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 e-mail: ssalam@cisco.com Ali Sajassi Cisco Systems, Inc. 170 West Tasman Drive San Jose, CA 95134 e-mail: sajassi@cisco.com Martini, et al. [Page 36] Internet Draft draft-martini-pwe3-iccp-00.txt June 2008 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 Martini, et al. [Page 37]