[Docs] [txt|pdf] [Tracker] [WG] [Email] [Nits]

Versions: 00 01 02 03 04 05 06 07 08 09 10 RFC 4204

Network Working Group               Jonathan P. Lang (Calient Networks)
Internet Draft                         Krishna Mitra (Calient Networks)
Expiration Date: January 2002             John Drake (Calient Networks)
                                    Kireeti Kompella (Juniper Networks)
                                       Yakov Rekhter (Juniper Networks)
                                            Lou Berger (Movaz Networks)
                                                Debanjan Saha (Tellium)
                                    Debashis Basak (Accelight Networks)
                                          Hal Sandick (Nortel Networks)
                                             Alex Zinin (Cisco Systems)
                                             Bala Rajagopalan (Tellium)

                                                              July 2002
                     Link Management Protocol (LMP)

                      draft-ietf-ccamp-lmp-00.txt

 Status of this Memo

   This document is an Internet-Draft and is in full conformance with
   all provisions of Section 10 of RFC2026 [RFC2026].

   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.

 Abstract

   Future networks will consist of photonic switches, optical
   crossconnects, and routers that may be configured with control
   channels, links, and bundled links.  This draft specifies a link
   management protocol (LMP) that runs between neighboring nodes and is
   used to manage traffic engineering (TE) links.  Specifically, LMP
   will be used to maintain control channel connectivity, verify the
   physical connectivity of the data-bearing channels, correlate the
   link property information, and manage link failures.  A unique
   feature of the fault management technique is that it is able to
   localize failures in both opaque and transparent networks,
   independent of the encoding scheme used for the data.


Lang/Mitra et al                                              [Page 1]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

Table of Contents

   1. Introduction ................................................   3
   2. LMP Overview ................................................   4
   3. Control Channel Management ..................................   6
      3.1 Parameter Negotiation ...................................   7
      3.2 Hello Protocol ..........................................   8
          3.2.1  Hello Parameter Negotiation ......................   8
          3.2.2  Fast Keep-alive ..................................   9
          3.2.3  Administrative Down ..............................  10
          3.2.4  Degraded (DEG) State .............................  10
   4. Link Property Correlation ...................................  10
   5. Verifying Link Connectivity .................................  11
      5.1 Example of Link Connectivity Verification ...............  14
   6. Fault Management ............................................  15
      6.1 Fault Detection .........................................  15
      6.2 Fault Localization Procedure ............................  16
      6.3 Examples of Fault Localization ..........................  16
      6.4 Channel Activation Indication ...........................  17
      6.5 Channel Deactivation Indication .........................  18
   7. LMP Authentication ..........................................  18
   8. LMP Finite State Machine ....................................  18
      8.1 Control Channel FSM .....................................  18
          8.1.1  Control Channel States ...........................  18
          8.1.2  Control Channel Events ...........................  19
          8.1.3  Control Channel FSM Description ..................  22
      8.2 TE Link FSM .............................................  23
          8.2.1  TE link States ...................................  23
          8.2.2  TE link Events ...................................  24
          8.2.3  TE link FSM Description ..........................  25
      8.3 Data Link FSM ...........................................  26
          8.3.1  Data Link States .................................  26
          8.3.2  Data Link Events .................................  26
          8.3.3  Active Data Link FSM Description .................  28
          8.3.4  Passive Data Link FSM Description ................  29
   9. LMP Message Formats .........................................  30
      9.1 Common Header ...........................................  30
      9.2 LMP TLV Format ..........................................  32
      9.3 Authentication ..........................................  33
      9.4 Parameter Negotiation ...................................  35
      9.5 Hello ...................................................  39
      9.6 Link Verification .......................................  39
      9.7 Link Summary ............................................  48
      9.8 Fault Management ........................................  52
   10. Security Conderations ......................................  56
   11. References .................................................  56
   12. Acknowledgments ............................................  58
   13. Authors' Addresses  ........................................  58





Lang et al                                                    [Page 2]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   Changes from previous version:

   o  Modified the LMP Common Header to include (a) the CCId for
      Control Channel specific messages or (b) the TE Link Id for link
      specific messages.
   o  Removed the ChannelFailNack message.
   o  Removed LMPCapabilities TLV from Config message.
   o  Made editorial changes.
   o  Made corrections to the FSMs.

1. Introduction

   Future networks will consist of photonic switches (PXCs), optical
   crossconnects (OXCs), routers, switches, DWDM systems, and add-drop
   multiplexors (ADMs) that use a common control plane [e.g.,
   Generalized MPLS (GMPLS)] to dynamically provision resources and to
   provide network survivability using protection and restoration
   techniques.  A pair of nodes (e.g., two PXCs) may be connected by
   thousands of fibers, and each fiber may be used to transmit multiple
   wavelengths if DWDM is used.  Furthermore, multiple fibers and/or
   multiple wavelengths may be combined into a single traffic-
   engineering (TE) link for routing purposes.  To enable communication
   between nodes for routing, signaling, and link management, control
   channels must be established between the node pair; however, the
   interface over which the control messages are sent/received may not
   be the same interface over which the data flows.  This draft
   specifies a link management protocol (LMP) that runs between
   neighboring nodes and is used to manage TE links.

   In this draft, we will follow the naming convention of [LAMBDA] and
   use OXC to refer to all categories of optical crossconnects,
   irrespective of the internal switching fabric. We distinguish
   between crossconnects that require opto-electronic conversion,
   called digital crossconnects (DXCs), and those that are all-optical,
   called photonic switches or photonic crossconnects (PXCs) - referred
   to as pure crossconnects in [LAMBDA], because the transparent nature
   of PXCs introduces new restrictions for monitoring and managing the
   data links.  LMP can be used for any type of node, enhancing the
   functionality of traditional DXCs and routers, while enabling PXCs
   and DWDMs to intelligently interoperate in heterogeneous optical
   networks.

   In GMPLS, the control channels between two adjacent nodes are no
   longer required to use the same physical medium as the data-bearing
   links between those nodes. For example, a control channel could use
   a separate wavelength or fiber, an Ethernet link, or an IP tunnel
   through a separate management network.  A consequence of allowing
   the control channel(s) between two nodes to be physically diverse
   from the associated data links is that the health of a control
   channel does not necessarily correlate to the health of the data
   links, and vice-versa.  Therefore, a clean separation between the
   fate of the control channel and data-bearing links must be made.

Lang et al                                                    [Page 3]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   New mechanisms must be developed to manage the data-bearing links,
   both in terms of link provisioning and fault management.

   For the purposes of this document, a data-bearing link may be either
   a "port" or a "component link" depending on its multiplexing
   capability; component links are multiplex capable, whereas ports are
   not multiplex capable.  This distinction is important since the
   management of such links (including, for example, resource
   allocation, label assignment, and their physical verification) is
   different based on their multiplexing capability.  For example, a
   SONET crossconnect with OC-192 interfaces may be able to demultiplex
   the OC-192 stream into four OC-48 streams.  If multiple interfaces
   are grouped together into a single TE link using link bundling
   [BUNDLE], then the link resources must be identified using three
   levels: TE link Id, component interface Id, and timeslot label.
   Resource allocation happens at the lowest level (timeslots), but
   physical connectivity happens at the component link level.  As
   another example, consider the case where a PXC transparently
   switches OC-192 lightpaths.  If multiple interfaces are once again
   grouped together into a single TE link, then link bundling [BUNDLE]
   is not required and only two levels of identification are required:
   TE link Id and port Id.  Both resource allocation and physical
   connectivity happen at the lowest level (i.e. port level).

   LMP is designed to support aggregation of one or more data-bearing
   links into a TE link (either ports into TE links, or component links
   into TE links).

2. LMP Overview

   The two core procedures of LMP are control channel management and
   link property correlation.  Control channel management is used to
   establish and maintain control channels between adjacent nodes.
   This is done using a Config message exchange and a fast keep-alive
   mechanism between the nodes.  The latter is required if lower-level
   mechanisms are not available to detect control channel failures.
   Link property correlation is used to synchronize the TE link
   properties and verify configuration.

   LMP requires that a pair of nodes have at least one active bi-
   directional control channel between them.  The two directions of the
   control channel are coupled together using the LMP Config message
   exchange.  All LMP messages are IP encoded [except in some cases,
   the Test Message which may be limited by the transport mechanism for
   in-band messaging].  The link level encoding of the control channel
   is outside the scope of this document.

   An ôLMP adjacencyö is formed between two nodes.  Multiple control
   channels may be active simultaneously for each adjacency; however,
   each control channel MUST individually negotiate its control channel
   parameters, and each active control channel that chooses to use the
   fast keep-alive MUST exchange LMP Hello packets to maintain

Lang et al                                                    [Page 4]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   connectivity.  The remaining LMP control messages MAY be transmitted
   over any of the active control channels between a pair of adjacent
   nodes.

   The link property correlation function of LMP is designed to
   aggregate multiple data links (ports or component links) into a TE
   link and to synchronize the properties of the TE link.  As part of
   the link property correlation function, a LinkSummary message
   exchange is defined.  The LinkSummary message includes the local and
   remote TE Link Ids, a list of all data links that comprise the TE
   link, and various link properties.  A LinkSummaryAck or
   LinkSummaryNack message MUST be sent in response to the receipt of a
   LinkSummary message indicating agreement or disagreement on the link
   properties.

   LMP messages are transmitted reliably using MessageIds, and LMP
   messages MUST be processed in-order.  No more than one MessageId may
   be included in an LMP message.  For control channel specific
   messages, the MessageId field MUST be unique on a per Control
   Channel Id basis.  For TE link specific messages, the MessageId
   field MUST be unique on a per TE link basis.  This value of the
   MessageId field is incremented and only decreases when the value
   wraps.

   In this draft, two additional procedures are defined: link
   connectivity verification and fault management.  These procedures
   are particularly useful when the control channels are physically
   diverse from the data-bearing links.   Link connectivity
   verification is used to verify the physical connectivity of the
   data-bearing links between the nodes and exchange the Interface Ids;
   Interface Ids are used in GMPLS signling, either Port labels or
   Component Interface Ids, depending on the configuration.  The link
   verification procedure uses in-band Test messages that are sent over
   the data-bearing links and TestStatus messages that are transmitted
   back over the control channel.  Note that the Test message is the
   only LMP message that must be transmitted over the data-bearing
   link.  The fault management scheme uses ChannelActive,
   ChannelDeactive, and ChannelFail message exchanges between adjacent
   nodes to localize failures in both opaque and transparent networks,
   independent of the encoding scheme used for the data.  As a result,
   both local span and end-to-end path protection/restoration
   procedures can be initiated.

   For the LMP link connectivity verification procedure, the free
   (unallocated) data-bearing links MUST be opaque (i.e., able to be
   terminated); however, once a data link is allocated, it may become
   transparent.  The LMP link connectivity verification procedure is
   coordinated using a BeginVerify message exchange over a control
   channel.  To support various degrees of transparency (e.g.,
   examining overhead bytes, terminating the payload, etc.), and hence,
   different mechanisms to transport the Test messages, a Verify
   Transport Mechanism is included in the BeginVerify and

Lang et al                                                    [Page 5]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   BeginVerifyAck messages.  Note that there is no requirement that all
   of the data-bearing links must be terminated simultaneously, but at
   a minimum, they must be able to be terminated one at a time.  There
   is also no requirement that the control channel and TE link use the
   same physical medium; however, the control channel MUST terminate on
   the same two nodes that the TE link spans.  Since the BeginVerify
   message exchange coordinates the Test procedure, it also naturally
   coordinates the transition of the data links between opaque and
   transparent modes.

   The LMP fault management procedure is based on the following
   messages:  ChannelActive, ChannelDeactive, and ChannelFail message
   exchanges.  The ChannelActive message is used to indicate that one
   or more data-bearing channels are now carrying user data.  This is
   particularly useful for detecting unidirectional channel failures in
   the transparent case.  Upon receipt of a ChannelActive message, the
   data-bearing channels MUST move to the UP state (if they are not
   already there) and fault monitoring SHOULD be verified for the
   corresponding data channels.  The ChannelDeactive message is the
   complement of the ChannelActive message and is used to indicate the
   channels MUST move to the DOWN state.  The ChannelFail message is
   used to indicate that one or more active data channels have failed
   or an entire TE link has failed.  Receipt of the ChannelActive,
   ChannelDeactive, and ChannelFail messages MUST be acknowledged.

   The organization of the remainder of this document is as follows.
   In Section 3, we discuss the role of the control channel and the
   messages used to establish and maintain link connectivity.  In
   Section 4, the link property correlation function using the
   LinkSummary message exchange is described.  The link verification
   procedure is discussed in Section 5.  In Section 6, we show how LMP
   will be used to isolate link and channel failures within the optical
   network.  Several finite state machines (FSMs) are given in Section
   8 and the message formats are defined in Section 9.

3. Control Channel Management

   To initiate an LMP adjacency between two nodes, one or more bi-
   directional control channels MUST be activated.  The control
   channels can be used to exchange control-plane information such as
   link provisioning and fault management information (implemented
   using a messaging protocol such as LMP, proposed in this draft),
   path management and label distribution information (implemented
   using a signaling protocol such as RSVP-TE [RSVP-TE] or CR-LDP [CR-
   LDP]), and network topology and state distribution information
   (implemented using traffic engineering extensions of protocols such
   as OSPF [OSPF-TE] and IS-IS [ISIS-TE]).

   For the purposes of LMP, we do not specify the exact implementation
   of the control channel; it could be, for example, a separate
   wavelength or fiber, an Ethernet link, an IP tunnel through a
   separate management network, or the overhead bytes of a data-bearing

Lang et al                                                    [Page 6]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   link.  Rather, we assign a node-wide unique 32-bit non-zero integer
   control channel identifier (CCId) to each direction of the control
   channel.  This identifier comes from the same space as the
   unnumbered interface Id.  One possible way to assign a CCId is to
   use the IP address or ifindex of the interface.  Furthermore, we
   define all LMP messages to be IP encoded.  This means that the link
   level encoding of the control channel is not part of LMP.

   The control channel can be either explicitly configured or
   automatically selected, however, for the purpose of this document we
   will assume the control channel is explicitly configured. Note that
   for in-band signaling, a control channel could be explicitly
   configured on a particular data-bearing link.

   Control channels exist independently of TE links and multiple
   control channels may be active simultaneously between a pair of
   nodes.  Each LMP control channel MUST individually negotiate its
   control channel parameters, and each active control channel MUST
   exchange LMP Hello packets to maintain LMP connectivity if other
   mechanisms are not available.  Since control channels are
   electrically terminated at each node, lower layers (e.g., SONET/SDH)
   may also be used to detect control channel failures.

   There are four control channel messages that are used to manage
   individual control channels.  They are the Config, ConfigAck,
   ConfigNack, and Hello messages. These messages MUST be transmitted
   on the channel to which they refer.  All other LMP control channel
   messages may be transmitted over any of the active control channels
   between a pair of LMP adjacent nodes.

   In order to maintain an LMP adjacency, it is necessary to have at
   least one active control channel between a pair of adjacent nodes
   (recall that multiple control channels can be active simultaneously
   between a pair of nodes).  In the event of a control channel
   failure, alternate active control channels can be used and it may be
   possible to activate additional control channels as mentioned below.

3.1. Parameter Negotiation

   Control channel activation begins with a parameter negotiation
   exchange using Config, ConfigAck, and ConfigNack messages.  The
   contents of these messages are built using TLV triplets.  Config
   TLVs can be either negotiable or non-negotiable (identified by the N
   flag in the TLV header).  Negotiable TLVs can be used to let the
   devices agree on certain values.  Non-negotiable TLVs are used for
   announcement of specific values that do not need, or do not allow,
   negotiation.

   To begin control channel activation, a node MUST transmit a Config
   message to the remote node.  The Config message contains the
   senderÆs Node ID, a MessageId for reliable messaging, and one or
   more Config TLVs.  It is possible that both the local and remote

Lang et al                                                    [Page 7]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   nodes initiate the configuration procedure at the same time.  To
   avoid ambiguities, the node with the higher Node Id wins the
   contention; the node with the lower Node Id MUST stop transmitting
   the Config message and respond to the Config message it received.

   The Config message MUST be periodically transmitted until (1) it
   receives a ConfigAck or ConfigNack message, (2) a timeout expires
   and no ConfigAck or ConfigNack message has been received, or (3) it
   receives a Config message from the remote node and has lost the
   contention (e.g., the Node Id of the remote node is higher than the
   Node Id of the local node).  Both the retransmission interval and
   the timeout period are local configuration parameters.

   The Config message MUST include the HelloConfig TLV.

   The ConfigAck message is used to acknowledge receipt of the Config
   message and express agreement on ALL of the configured parameters
   (both negotiable and non-negotiable).  The ConfigNack message is
   used to acknowledge receipt of the Config message, indicate which
   (if any) non-negotiable parameters are unacceptable, and propose
   alternate values for the negotiable parameters.

   If a node receives a ConfigNack message with acceptable alternate
   values for negotiable parameters, the node SHOULD transmit a Config
   message using these values for those parameters and

   In the case where multiple control channels use the same physical
   interface, the parameter negotiation exchange is performed for each
   control channel.  The various LMP parameter negotiation messages are
   associated with their corresponding control channels by their node-
   wide unique identifiers (CCIds).

3.2. Hello Protocol

   Once a control channel is activated between two adjacent nodes, the
   LMP Hello protocol can be used to maintain control channel
   connectivity between the nodes and to detect control channel
   failures.  The LMP Hello protocol is intended to be a lightweight
   keep-alive mechanism that will react to control channel failures
   rapidly so that IGP Hellos are not lost and the associated link-
   state adjacencies are not removed unnecessarily.  Furthermore, if
   RSVP is used for signaling, then the RSVP Hello [RSVP-TE] is not
   needed to detect link-layer failures since the LMP Hellos will
   detect them.

3.2.1. Hello Parameter Negotiation

   Before sending Hello messages, the HelloInterval and
   HelloDeadInterval parameters MUST be agreed upon by the local and
   remote nodes.  These parameters are exchanged as a HelloConfig TLV
   object in the Config message.  The HelloInterval indicates how
   frequently LMP Hello messages will be sent, and is measured in

Lang et al                                                    [Page 8]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   milliseconds (ms).  For example, if the value were 150, then the
   transmitting node would send the Hello message at least every 150ms.
   The HelloDeadInterval indicates how long a device should wait to
   receive a Hello message before declaring a control channel dead, and
   is measured in milliseconds (ms).  The HelloDeadInterval MUST be
   greater than the HelloInterval, and SHOULD be at least 3 times the
   value of HelloInterval.

   When a node has either sent or received a ConfigAck message, it may
   begin sending Hello messages.  Once it has both sent and received a
   Hello message, the control channel moves to the UP state.  (It is
   also possible to move to the UP state without sending Hellos if
   other methods are used to indicate bi-directional control-channel
   connectivity.)  If, however, a node receives a ConfigNack message
   instead of a ConfigAck message, the node MUST not send Hello
   messages and the control channel SHOULD not move to the UP state.
   See Section 8.1 for the complete control channel FSM.

3.2.2. Fast Keep-alive

   Each Hello message contains two sequence numbers: the first sequence
   number (TxSeqNum) is the sequence number for this Hello message and
   the second sequence number (RcvSeqNum) is the sequence number of the
   last Hello message received over this control channel from the
   adjacent node. Each node increments its sequence number when it sees
   its current sequence number reflected in Hellos received from its
   peer. The sequence numbers start at 1 and wrap around back to 2; 0
   is used in the RcvSeqNum to indicate that a Hello has not yet been
   seen.

   Under normal operation, the difference between the RcvSeqNum in a
   Hello message that is received and the local TxSeqNum that is
   generated will be at most 1.  This difference can be more than one
   only when a control channel reboots.

   Having sequence numbers in the Hello messages allows each node to
   verify that its peer is receiving its Hello messages. This provides
   a two-fold service. First, the remote node will detect that a
   control channel has rebooted if TxSeqNum=1.  If this occurs, the
   remote node will indicate its knowledge of the reboot by setting
   RcvSeqNum=1 in the Hello messages that it sends and SHOULD wait to
   receive a Hello message with TxSeqNum=2 before transmitting any
   messages other than Hello messages. Second, by including the
   RcvSeqNum in Hello packets, the local node will know which Hello
   packets the remote node has received.

   The following example illustrates how the sequence numbers operate:

   1)  After completing the configuration stage, Node A sends a Hello
       message with {TxSeqNum=1;RcvSeqNum=0}.
   2)  When Node A receives a Hello with {TxSeqNum=1;RcvSeqNum=1}, it
       sends Hellos with {TxSeqNum=2;RcvSeqNum=1}.

Lang et al                                                    [Page 9]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   3)  After some time, the control channel on Node B reboots.
   4)  Node A is sending Hellos with {TxSeqNum=45;RcvSeqNum=44} and
       receives a Hello from Node B with {TxSeqNum=1;RcvSeqNum=0},
       indicating that Node B has rebooted.  Node A sends Hello
       messages with {TxSeqNum=45;RcvSeqNum=1}.
   4)  When Node A receives a Hello with {TxSeqNum=2;RcvSeqNum=45}, it
       sends Hellos with {TxSeqNum=46;RcvSeqNum=2}.

3.2.3. Administrative Down

   To ensure that bringing a control channel DOWN for administration
   purposes is done gracefully, a ControlChannelDown flag is available
   in the Common Header of LMP packets.  When data links are still in
   use between a pair of nodes, a control channel SHOULD only be taken
   down administratively when there are other active control channels
   that can be used to manage the data links.

   When a node receives LMP packets with the ControlChannelDown flag
   set, it may stop sending Hello packets.

3.2.4. Degraded State

   A consequence of allowing the control channels to be physically
   diverse from the associated data links is that there may be no
   active control channels available, but the data links are still in
   use. For many applications, it is unacceptable to tear down a link
   that is carrying user traffic simply because the control channel is
   no longer available; however, the traffic that is using the data
   links may no longer be guaranteed the same level of service.  Hence
   the TE link is in a Degraded state.

   When a TE link is in the Degraded state, routing and signaling
   SHOULD be notified so that new connections are not accepted and
   resources are no longer advertised for the TE link.

4. Link Property Correlation

   As part of LMP, a link property correlation exchange is defined
   using the LinkSummary, LinkSummaryAck, and LinkSummaryNack messages.
   The contents of these messages are built using TLV triplets.
   LinkSummary TLVs can be either negotiable or non-negotiable
   (identified by the N flag in the TLV header).  Negotiable TLVs can
   be used to let both sides agree on certain link parameters.  Non-
   negotiable TLVs are used for announcement of specific values that do
   not need, or do not allow, negotiation.

   The LinkSummary message is used to aggregate multiple data links
   (either ports or component links) into a TE link; exchange,
   correlate, or change TE link parameters; and exchange, correlate, or
   change Interface Ids (either Port Ids or Component Interface Ids).



Lang et al                                                   [Page 10]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   The LinkSummary message can be exchanged at any time a link is UP
   and not in the Verification process.  The LinkSummary message MUST
   be periodically transmitted until (1) the node receives a
   LinkSummaryAck or LinkSummaryNack message or (2) a timeout expires
   and no LinkSummaryAck or LinkSummaryNack message has been received.
   Both the retransmission interval and the timeout period are local
   configuration parameters.

   If the LinkSummary message is received from a remote node and the
   Interface Id mappings match those that are stored locally, then the
   two nodes have agreement on the Verification procedure (see Section
   5).  If the verification procedure is not used, the LinkSummary
   message can be used to verify agreement on manual configuration.

   The LinkSummaryAck message is used to signal agreement on the
   Interface Id mappings and link property definitions.  Otherwise, a
   LinkSummaryNack message MUST be transmitted, indicating which
   Interface mappings are not correct and/or which link properties are
   not accepted. If a LinkSummaryNack message indicates that the
   Interface Id mappings are not correct and the link verification
   procedure is enabled, the link verification process SHOULD be
   repeated for all mismatched free data links; if an allocated data
   link has a mapping mismatch, it SHOULD be flagged and verified when
   it becomes free.  If a LinkSummaryNack message includes negotiable
   parameters, then acceptable values for those parameters MUST be
   included.  If a LinkSummaryNack message is received and includes
   negotiable parameters, then the initiator of the LinkSummary message
   MUST send a new LinkSummary message.  The new LinkSummary message
   SHOULD include new values for the negotiable parameters.  These
   values SHOULD take into account the acceptable values received in
   the LinkSummaryNack message.

   It is possible that the LinkSummary message could grow quite large
   due to the number of Data Link TLVs.  Since the LinkSummary message
   is IP encoded, normal IP fragmentation should be used if the
   resulting PDU exceeds the MTU.

5. Verifying Link Connectivity

   In this section, we describe an optional procedure that may be used
   to verify the physical connectivity of the data-bearing links.  The
   procedure SHOULD be done when establishing a TE link, and
   subsequently, on a periodic basis for all unallocated (free) data
   links of the TE link.

   If the link connectivity procedure is not supported for the TE link,
   then a BeginVerifyNack message MUST be transmitted with Error Code
   =1, ôLink Verification Procedure not supported for this TE Linkö.

   A unique characteristic of all-optical PXCs is that the data-bearing
   links are transparent when allocated to user traffic.  This
   characteristic of PXCs poses a challenge for validating the

Lang et al                                                   [Page 11]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   connectivity of the data links since shining unmodulated light
   through a link may not result in received light at the next PXC.
   This is because there may be terminating (or opaque) elements, such
   as DWDM equipment, between the PXCs.  Therefore, to ensure proper
   verification of data link connectivity, we require that until the
   links are allocated, they must be opaque.  To support various
   degrees of opaqueness (e.g., examining overhead bytes, terminating
   the payload, etc.), and hence different mechanisms to transport the
   Test messages, a Verify Transport Mechanism is included in the
   BeginVerify and BeginVerifyAck messages.  There is no requirement
   that all data links be terminated simultaneously, but at a minimum,
   the data links MUST be able to be terminated one at a time.
   Furthermore, for the link verification procedure we assume that the
   nodal architecture is designed so that messages can be sent and
   received over any data link.  Note that this requirement is trivial
   for DXCs (and OEO devices in general) since each data link is
   received electronically before being forwarded to the next OEO
   device, but that in PXCs (and transparent devices in general) this
   is an additional requirement.

   To interconnect two nodes, a TE link is added between them, and at a
   minimum, there MUST be at least one active control channel between
   the nodes.  A TE link MUST include at least one data link.

   Once a control channel has been established between the two nodes,
   data link connectivity can be verified by exchanging Test messages
   over each of the data links specified in the TE link.  It should be
   noted that all LMP messages except the Test message are exchanged
   over the control channels and that Hello messages continue to be
   exchanged over each control channel during the data link
   verification process.  The Test message is sent over the data link
   that is being verified.  Data links are tested in the transmit
   direction as they are unidirectional, and therefore, it may be
   possible for both nodes to exchange the Test messages
   simultaneously.

   To initiate the link verification procedure, the local node MUST
   send a BeginVerify message over a control channel.  The BeginVerify
   message contains fields for the local and remote TE Link Ids.  When
   non-zero, these fields limit the scope of the data links being
   verified to the corresponding TE link.  If both fields are zero, the
   data links can span multiple TE links and/or they may comprise a TE
   link that is yet to be configured.

   The BeginVerify message contains the number of data links that are
   to be verified; the interval (called VerifyInterval) at which the
   Test messages will be sent; the encoding scheme and transport
   mechanisms that are supported; the data rate for Test messages; and,
   when the data links correspond to fibers, the wavelength over which
   the Test messages will be transmitted.



Lang et al                                                   [Page 12]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   The BeginVerify message MUST be periodically transmitted until (1)
   the node receives either a BeginVerifyAck or BeginVerifyNack message
   to accept or reject the verify process or (2) a timeout expires and
   no BeginVerifyAck or BeginVerifyNack message has been received.
   Both the retransmission interval and the timeout period are local
   configuration parameters.

   If the remote node receives a BeginVerify message and it is ready to
   process Test messages, it MUST send a BeginVerifyAck message back to
   the local node specifying the desired transport mechanism for the
   TEST messages.  The remote node includes a 32-bit node unique
   VerifyId in the BeginVerifyAck message.  The VerifyId is then used
   in all corresponding verification messages to differentiate them
   from different LMP peers and/or parallel Test procedures.  When the
   local node receives a BeginVerifyAck message from the remote node,
   it may begin testing the data links by transmitting periodic Test
   messages over each data link.  The Test message includes the
   VerifyId and the local Interface Id for the associated data link.
   The remote node MUST send either a TestStatusSuccess or a
   TestStatusFailure message in response for each data link.  A
   TestStatusAck message MUST be sent to confirm receipt of the
   TestStatusSuccess and TestStatusFailure messages.

   The local (transmitting) node sends a given Test message
   periodically (at least once every VerifyInterval ms) on the
   corresponding data link until (1) it receives a correlating
   TestStatusSuccess or TestStatusFailure message on the control
   channel from the remote (receiving) node or (2) all active control
   channels between the two nodes have failed. The remote node will
   send a given TestStatus message periodically over the control
   channel until it receives either a correlating TestStatusAck message
   or an EndVerify message is received over the control channel.

   It is also permissible for the sender to terminate the Test
   procedure without receiving a TestStatusSuccess or TestStatusFailure
   message by sending an EndVerify message.

   Message correlation is done using message identifiers and the Verify
   Id; this enables verification of data links, belonging to different
   link bundles or LMP sessions, in parallel.

   When the Test message is received, the received Interface Id (used
   in GMPLS as either a Port label or Component Interface Identifier
   depending on the configuration) is recorded and mapped to the local
   Interface Id for that data link, and a TestStatusSuccess message
   MUST be sent.  The TestStatusSuccess message includes the local
   Interface Id and the remote Interface Id (received in the Test
   message), along with the VerifyId received in the Test message.  The
   receipt of a TestStatusSuccess message indicates that the Test
   message was detected at the remote node and the physical
   connectivity of the data link has been verified.  When the
   TestStatusSuccess message is received, the local node SHOULD mark

Lang et al                                                   [Page 13]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   the data link as UP and send a TestStatusAck message to the remote
   node.  If, however, the Test message is not detected at the remote
   node within an observation period (specified by the
   VerifyDeadInterval), the remote node will send a TestStatusFailure
   message over the control channel indicating that the verification of
   the physical connectivity of the data link has failed.  When the
   local node receives a TestStatusFailure message, it SHOULD mark the
   data link as FAILED and send a TestStatusAck message to the remote
   node.  When all the data links on the list have been tested, the
   local node SHOULD send an EndVerify message to indicate that testing
   is complete on this link.

   The EndVerify message will be periodically transmitted until (1) an
   EndVerifyAck message has been received or (2) a timeout expires and
   no EndVerifyAck message has been received.  Both the retransmission
   interval and the timeout period are local configuration parameters.

   Both the local and remote nodes SHOULD maintain the complete list of
   Interface Id mappings for correlation purposes.

5.1. Example of Link Connectivity Verification

   Figure 1 shows an example of the link verification scenario that is
   executed when a link between PXC A and PXC B is added. In this
   example, the TE link consists of three free ports (each transmitted
   along a separate fiber) and is associated with a bi-directional
   control channel (indicated by a "c"). The verification process is as
   follows: PXC A sends a BeginVerify message over the control channel
   ôcö to PXC B indicating it will begin verifying the ports.  PXC B
   receives the BeginVerify message, assigns a VerifyId to the Test
   procedure, and returns the BeginVerifyAck message over the control
   channel to PXC A.  When PXC A receives the BeginVerifyAck message,
   it begins transmitting periodic Test messages over the first port
   (Interface Id=1). When PXC B receives the Test messages, it maps the
   received Interface Id to its own local Interface Id = 10 and
   transmits a TestStatusSuccess message over the control channel back
   to PXC A.  The TestStatusSuccess message includes both the local and
   received Interface Ids for the port as well as the VerifyId.  PXC A
   will send a TestStatusAck message over the control channel back to
   PXC B indicating it received the TestStatusSuccess message.  The
   process is repeated until all of the ports are verified. At this
   point, PXC A will send an EndVerify message over the control channel
   to PXC B to indicate that testing is complete; PXC B will respond by
   sending an EndVerifyAck message over the control channel back to PXC
   A.








Lang et al                                                   [Page 14]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   +---------------------+                      +---------------------+
   +                     +                      +                     +
   +      PXC A          +<-------- c --------->+         PXC B       +
   +                     +                      +                     +
   +                     +                      +                     +
   +                   1 +--------------------->+ 10                  +
   +                     +                      +                     +
   +                     +                      +                     +
   +                   2 +                /---->+ 11                  +
   +                     +          /----/      +                     +
   +                     +     /---/            +                     +
   +                   3 +----/                 + 12                  +
   +                     +                      +                     +
   +                     +                      +                     +
   +                   4 +--------------------->+ 14                  +
   +                     +                      +                     +
   +---------------------+                      +---------------------+

      Figure 2:  Example of link connectivity between PXC A and PXC B.

6. Fault Management

   In this section, we describe an optional LMP procedure that is used
   to manage failures by rapid notification of link or channel
   failures.  The scope of this procedure is within a TE link, and as
   such, the use of this procedure is negotiated as part of the
   LinkSummary exchange.  The procedure can be used to rapidly isolate
   link failures and is designed to work for both unidirectional and
   bi-directional LSPs.

   Recall that a TE link connecting two nodes may consist of a number
   of data links (ports or component links). If one or more data links
   fail between two nodes, a mechanism must be used for rapid failure
   notification so that appropriate protection/restoration mechanisms
   can be initiated.  An important implication of using PXCs is that
   traditional methods that are used to monitor the health of allocated
   data links in OEO nodes (e.g., DXCs) may no longer be appropriate,
   since PXCs are transparent to the bit-rate, format, and wavelength.
   Instead, fault detection is delegated to the physical layer (i.e.,
   loss of light or optical monitoring of the data) instead of layer 2
   or layer 3.

6.1. Fault Detection

   Fault detection should be handled at the layer closest to the
   failure; for optical networks, this is the physical (optical) layer.
   One measure of fault detection at the physical layer is detecting
   loss of light (LOL). Other techniques for monitoring optical signals
   are still being developed and will not be further considered in this
   document. However, it should be clear that the mechanism used for
   fault notification in LMP is independent of the mechanism used to


Lang et al                                                   [Page 15]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   detect the failure, but simply relies on the fact that a failure is
   detected.

6.2. Fault Localization Procedure

   If data links fail between two PXCs, the power monitoring system in
   all of the downstream nodes may detect LOL and indicate a failure.
   To avoid multiple alarms stemming from the same failure, LMP
   provides a ChannelFail notification message.  This message may be
   used to indicate that a single data channel has failed, multiple
   data channels have failed, or an entire TE link has failed.  Failure
   correlation is done locally at each node upon receipt of the
   ChannelFail message.

   As part of the fault localization, a downstream node that detects
   data link failures will send a ChannelFail message to its upstream
   neighbor (bundling together the notification of all of the failed
   data links).  An upstream node that receives the ChannelFail message
   MUST send a ChannelFailAck message to the downstream node indicating
   it has received the ChannelFail message.  The upstream node should
   correlate the failure to see if the failure is also detected locally
   for the corresponding LSP(s).  If, for example, the failure has not
   been detected on the input of the upstream node or internally, then
   the upstream node will have localized the failure.  Once the failure
   has been localized, the signaling protocols can be used to initiate
   span or path protection/restoration procedures.

   If all of the data links of a TE link have failed, then the upstream
   node MAY be notified of the TE link failure without specifying that
   each data link of the TE link has failed.  This is done by sending a
   ChannelFail message identifying the TE Link without any including
   any Failure TLVs.

6.3. Examples of Fault Localization

   In Fig. 2, a sample network is shown where four PXCs are connected
   in a linear array configuration.  The control channels are bi-
   directional and are labeled with a "c".  All LSPs are uni-
   directional going left to right.

   In the first example [see Fig. 2(A)], there is a failure on a single
   data link between PXC2 and PXC3.  Both PXC3 and PXC4 will detect the
   failure and each node will send a ChannelFail message to the
   corresponding upstream node (PXC3 will send a message to PXC2 and
   PXC4 will send a message to PXC3). When PXC3 receives the
   ChannelFail message from PXC4, it returns a ChannelFailAck message
   back to PXC4 and correlates the failure locally. Upon receipt of the
   ChannelFailAck message, PXC4 will move the associated ports into a
   standby state. When PXC2 receives the ChannelFail message from PXC3,
   it also returns a ChannelFailAck message.  When PXC2 correlates the
   failure and verifies that it is CLEAR, it has localized the failure
   to the data link between PXC2 and PXC3.

Lang et al                                                   [Page 16]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001


   In the second example [see Fig. 2(B)], there is a failure on three
   data links between PXC3 and PXC4. In this example, PXC4 has
   correlated the failures and will send a bundled ChannelFail message
   for the three failures to PXC3. PXC3 will correlate the failures and
   localize them to the channels between PXC3 and PXC4.

   In the last example [see Fig. 2(C)], there is a failure on the
   tributary link of the ingress node (PXC1) to the network. Each
   downstream node will detect the failure on the corresponding input
   ports and send a ChannelFail message to the upstream neighboring
   node. When PXC2 receives the message from PXC3, it will return a
   ChannelFailAck message to PXC3 and correlate the failure locally
   (PXC3 and PXC4 will also act accordingly). Since PXC1 is the ingress
   node to the optical network, it will correlate the failure and
   localize the failure to the data link between itself and the network
   element outside the optical network.

       +-------+        +-------+        +-------+        +-------+
       + PXC 1 +        + PXC 2 +        + PXC 3 +        + PXC 4 +
       +       +-- c ---+       +-- c ---+       +-- c ---+       +
   ----+---\   +        +       +        +       +        +       +
       +    \--+--------+-------+---\    +       +        +    /--+--->
   ----+---\   +        +       +    \---+-------+---##---+---/   +
       +    \--+--------+-------+--------+-------+---##---+-------+--->
   ----+-------+--------+-------+--------+-------+---##---+-------+--->
   ----+-------+--------+---\   +        +       +  (B)   +       +
       +       +        +    \--+---##---+--\    +        +       +
       +       +        +       +   (A)  +   \   +        +       +
   -##-+--\    +        +       +        +    \--+--------+-------+--->
   (C) +   \   +        +    /--+--------+---\   +        +       +
       +    \--+--------+---/   +        +    \--+--------+-------+--->
       +       +        +       +        +       +        +       +
       +-------+        +-------+        +-------+        +-------+

          Figure 3:     We show three types of data link failures
          (indicated by ## in the figure):  (A) a single data link
          fails between two PXCs, (B) three data links fail between two
          PXCs, and (C) a single data link fails on the tributary input
          of PXC 1.  The control channel connecting two PXCs is
          indicated with a "c".

6.4. Channel Activiation Indication

   The ChannelActive message is used to notify the downstream
   neighboring node that the data link is in the Active state.  This is
   particularly useful in networks with transparent nodes where the
   status of data links may need to be triggered using control channel
   messages.  For example, if a data link is pre-provisioned and the
   physical link fails after verification and before inserting user
   traffic, the pair of nodes need a mechanism to indicate the data
   link is active or they may not be able to detect the failure.

Lang et al                                                   [Page 17]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001


   The ChannelActive message is used to indicate that a channel or
   group of channels are now active.  The ChannelActiveAck message MUST
   be transmitted upon receipt of a ChannelActive message.  When a
   ChannelActive message is received, the corresponding data link(s)
   MUST be put into the Active state.  If upon putting them into the
   Active state, a failure is detected, the ChannelFail message MUST be
   transmitted as described in Section 6.2.

6.5. Channel Deactiviation Indication

   The ChannelDeactive message is the counterpart to the ChannelActive
   message and is used to notify the downstream neighboring node that
   the data link should be taken out of the Active state.

   The ChannelDeactiveAck message MUST be transmitted upon receipt of a
   ChannelActive message.  When a ChannelDeactive message is received,
   the corresponding data link(s) MUST be taken out of the Active
   state.

7. LMP Authentication

   LMP authentication is optional (included in the Common Header) and,
   if used, MUST be supported by both sides of the control channel.  The
   method used to authenticate LMP packets is based on the
   authentication technique used in [OSPF].  This uses cryptographic
   authentication using MD5.

   As a part of the LMP authentication mechanism, a flag is included in
   the LMP common header indicating the presence of authentication
   information.  Authentication information itself is appended to the
   LMP packet.  It is not considered to be a part of the LMP packet, but
   is transferred in the same IP packet.

   When the Authentication flag is set in the LMP packet header, an
   authentication data block is attached to the packet.  This block has
   a standard authentication header and a data portion.  The contents of
   the data portion depend on the authentication type.  Currently, only
   MD5 is supported for LMP.

8. LMP Finite State Machines

8.1. Control Channel FSM

   The control channel FSM defines the states and logics of operation
   of an LMP control channel.  The description of FSM state transitions
   and associated actions is given in Section 3.

8.1.1. Control Channel States

   A control channel can be in one of the states described below.
   Every state corresponds to a certain condition of the control

Lang et al                                                   [Page 18]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   channel and is usually associated with a specific type of LMP
   message that is periodically transmitted to the far end.

   Down:        This is the initial control channel state.  In this
                state, no attempt is being made to bring the control
                channel up and no LMP messages are sent.  The control
                channel parameters should be set to the initial values.

   ConfigSnd:   The control channel is in the parameter negotiation
                state.  In this state the node periodically sends a
                Config message, and is expecting the other side to
                reply with either a ConfigAck or ConfigNack message.
                The FSM does not transition into the Active state until
                the remote side positively acknowledges the parameters.

   ConfRcv:     The control channel is in the parameter negotiation
                state.  In this state, the node is waiting for
                acceptable configuration parameters from the remote
                side.  Once such parameters are received and
                acknowledged, the FSM can transition to the Active
                state.

   Active:      In this state the node periodically sends a Hello
                message and is waiting to receive a valid Hello
                message.  Once a valid Hello message is received, it
                can transition to the UP state.

   Up:          The CC is in an operational state.  The node receives
                valid Hello messages and sends Hello messages.

   GoingDown:   A CC may go into this state because of two reasons:
                administrative action, and a ControlChannelDown bit
                received in an LMP message.  While a CC is in this
                state, the node sets the ControlChannelDown bit in all
                the messages it sends.

8.1.2. Control Channel Events

   Operation of the LMP control channel is described in terms of FSM
   states and events.  Control channel Events are generated by the
   underlying protocols and software modules, as well as by the packet
   processing routines and FSMs of associated TE links.  Every event
   has its number and a symbolic name.  Description of possible control
   channel events is given below.

   1 : evBringUp:    This is an externally triggered event indicating
                     that the control channel negotiation should begin.
                     This event, for example, may be triggered by a
                     provisioner command or by the successful
                     completion of a control channel bootstrap
                     procedure.  Depending on the configuration, this
                     will trigger either

Lang et al                                                   [Page 19]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

                         1a) the sending of a Config message,
                         1b) a period of waiting to receive a Config
                              message from the remote node.

   2 : evCCDn:       This event is generated when there is indication
                     that the control channel is no longer available.

   3 : evConfDone:   This event indicates a ConfigAck message has been
                     received, acknowledging the Config parameters.

   4 : evConfErr:    This event indicates a ConfigNack message has been
                     received, rejecting the Config parameters.

   5 : evNewConfOK:  New Config message was received from neighbor and
                     positively Acknowledged.

   6 : evNewConfErr: New Config message was received from neighbor and
                     rejected with a ConfigNack message.

   7 : evContenWin:  New Config message was received from neighbor at
                     the same time a Config message was sent to the
                     neighbor.  The Local node wins the contention.  As
                     a result, the received Config message is ignored.

   8 : evContenLost: New Config message was received from neighbor at
                     the same time a Config message was sent to the
                     neighbor.  The Local node looses the contention.
                         8a) The Config message is positively
                              Acknowledged.
                         8b) The Config message is negatively
                              Acknowledged.

   9 : evAdminDown:  The administrator has requested that the control
                     channel is brought down administratively.

   10: evNbrGoesDn:  A packet with LinkDown flag is received from the
                     neighbor.

   11: evHelloRcvd:  A Hello packet with expected SeqNum has been
                     received.

   12: evHoldTimer:  The HelloDeadInterval timer has expired indicating
                     that no Hello packet has been received.  This
                     moves the control channel back into the
                     Negotiation state, and depending on the local
                     configuration, this will trigger either
                         12a) the sending of periodic Config messages,
                         12b) a period of waiting to receive Config
                              messages from the remote node.

   13: evSeqNumErr:  A Hello with unexpected SeqNum received and
                     discarded.

Lang et al                                                   [Page 20]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001


   14: evReconfig:   Control channel parameters have been reconfigured
                     and require renegotiation.
   15: evConfRet:    A retransmission timer has expired and a Config
                     message is resent.
   16: evHelloRet:   The HelloInterval timer has expired and a Hello
                     packet is sent.














































Lang et al                                                   [Page 21]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

8.1.3 Control Channel FSM Description

   Figure 4 illustrates operation of the control channel FSM
   in a form of FSM state transition diagram.

                               +--------+
                  +----------->|        |<--------------+
                  |            |  Down  |<----------+   |
                  |  +---------|        |<-------+  |   |
                  |  |         +--------+        |  |   |
                  |  |           |    ^    2,9,10| 2|  2|
                  |  |1b       1a|    |          |  |   |
                  |  |           v    | 2,9,10   |  |   |
                  |  |         +--------+        |  |   |
                  |  |      +->|        |<------+|  |   |
                  |  |  4,7,|  |ConfSnd |       ||  |   |
                  |  | 14,15+--|        |<----+ ||  |   |
                  |  |         +--------+     | ||  |   |
                  |  |       3,8a| |          | ||  |   |
                  |  | +---------+ |8b  14,12a| ||  |   |
                  |  | |           v          | ||  |   |
                  |  +-|------>+--------+     | ||  |   |
                  |    |    +->|        |-----|-|+  |   |
                  |    |6,14|  |ConfRcv |     | |   |   |
                  |    |    +--|        |<--+ | |   |   |
                  |    |       +--------+   | | |   |   |
                  |    |          5| ^      | | |   |   |
                  |    +---------+ | |      | | |   |   |
                  |              | | |      | | |   |   |
                  |              v v |6,12b | | |   |   |
                  |9,10        +--------+   | | |   |   |
                  +------------|        |   | | |   |   |
                  |         +--| Active |---|-+ |   |   |
                  |     5,16|  |        |-------|---+   |
                  |     13  +->|        |   |   |       |
                  |            +--------+   |   |       |
                  |             11| ^       |   |       |
                  |               | |5      |   |       |
                  |               v |  6,12b|   |       |
                  |9,10        +--------+   |   |12a,14 |
                  +------------|        |---+   |       |
                               |   Up   |-------+       |
                               |        |---------------+
                               +--------+
                                 |   ^
                                 |   |
                                 +---+
                                11,13,16
                       Figure 4: Control Channel FSM




Lang et al                                                   [Page 22]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   Event evCCDn always forces the FSM to the Down State.  Events
   evHoldTimer evReconfig always force the FSM to the Negotiation state
   (either ConfigSnd or ConfigRcv).

8.2 TE Link FSM

   The TE Link FSM defines the states and logics of operation of an LMP
   TE Link.

8.2.1 TE Link States

   An LMP TE link can be in one of the states described below. Every
   state corresponds to a certain condition of the TE link and is
   usually associated with a specific type of LMP message that is
   periodically transmitted to the far end via the associated control
   channel or in-band via the data links.

   Down:       There are no control channels available and no data
               links are allocated to the TE link.

   VrfBegin:   This state is valid only for the side initiating the
               verification process. In this state, the node
               periodically sends a BeginVerify message and expects an
               BeginVerifyAck or BeginVerifyNack message.  The
               BeginVerify messages include information about the data
               links in the BegVerify state.

   VrfProcess: In this state, two FSMs are performing the link
               verification procedure. The initiator periodically sends
               Test messages over the data links in the Testing state
               and waits for TestStatus messages to be received over a
               control channel.  The passive side listens for incoming
               link test messages on the data links in the PasvTst
               state.

   Summary:    In this state, the new TE link configuration is
               announced by periodically sending the LinkSummary
               messages over the control channel.

   Up:         This is the normal operational state of the TE link.  At
               least one primary CC is required to be operational
               between the nodes sharing the TE link.

   Degraded:   In this state, all primary CCs are down, but the TE link
               still includes some allocated data links.








Lang et al                                                   [Page 23]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

8.2.2 TE Link Events

   Operation of the LMP TE link is described in terms of FSM states and
   events. TE Link events are generated by the packet processing
   routines and by the FSMs of the associated primary control
   channel(s) and the data links. Every event has its number and a
   symbolic name. Description of possible control channel events is
   given below.

   1 : evCCUp:         First primary CC goes Up
   2 : evCCDown:       Last primary CC goes Down
   3 : evVerDone:      Verification done for all data links;
                       EndVerifyAck message received.  Send LinkSummary
                       message.
   4 : evVerify:       An external event indicates that the Link
                       verification procedure should begin.  Send
                       BeginVerify message.
   5 : evRecnfReq:     TE link has been reconfigured and the new
                       configuration needs to be announced/agreed upon.
   6 : evSummaryAck:   LinkSummaryAck message has been received
                       acknowledging the TE link configuration.
   7 : evLastCompDn:   The last allocated data link has been freed.
   8 : evStartVer:     BeginVerifyAck message has been received
                       indicating the remote node is ready to start
                       link verification.  This should trigger
                       evStartTst (event 3) of a data link FSM.
   9 : evTELinkOk:     An external event has indicated that the TE link
                       is available.
   10: evBeginRet:     Retransmission timer expires and no
                       BeginVerifyAck or BeginVerifyNack message has
                       been received.  BeginVerify message is resent.
   11: evSummaryRet:   Retransmission timer expires and no
                       LinkSummaryAck or LinkSummaryNack message has
                       been received.  LinkSummary message is resent.
   12: evChannFail:    ChannelFail message is received for TE link and
                       a ChannelFailAck message is transmitted.
   13: evSummaryNack1: LinkSummaryNack message has been received
                       indicating negotiable parameters not accepted.
                       Modify negotiable parameters and resend
                       LinkSummary.
   14: evSummaryNack2  LinkSummaryNack message received indicating
                       misconfiguration of non-negotiable parameters.
                       Free ports that are misconfigured are moved to
                       Down state.  Allocated ports that are
                       misconfigured are flagged.
   15: evSummaryNack3: LinkSummaryNack message has been received
                       indicating misconfiguration of non-negotiable
                       parameters for all ports.





Lang et al                                                   [Page 24]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

8.2.3 TE Link FSM Description

   Figure 5 illustrates operation of the LMP TE Link FSM in a form of
   FSM state transition diagram.

                                  +--------+
                    +------------>|        |
                    |      +----->|  Down  |
                    |      | +----|        |
                    |      | |    +--------+
                    |      | |        |
                    |      | |       4|
                    |      | |9       |
                    |      | |        v
                    |      | |    +--------+
                    |      | |  2 |        |<-+
                    |  +---|-|----| VrfBeg |  |10
                    |  |   | |    |        |--+
                    |  |   | |    +--------+
                    |  |   | |      8|    ^
                    |  |   | |       |    |
                    |  |   | |       |    +---------+
                    |  |   | |       v              |
                    |  |   | |    +-------+         |
                    |  |   | |  2 |       |         |
                    |  +---|-|----|VrfProc|         |
                    |  |   | |    |       |         |
                    |  |   | |    +-------+         |
                    |  |   | |       3|             |
                    |  |   | |        |  +----------+
                    |  |   | |        v  |4         |
                    |  |   | | 15 +-------+         |
                    |  |   +-|----|       |<-+      |
                    |  |     +--->|Summary|  |11,13 |
                    |  | +--------|       |--+      |
                    |  | |2  +--->+-------+         |
                    |  | |   |  6,14|   ^           |
                    |  | |   |      |   |           |
                    |  | |   |      |   |           |
                    |7 | |   |      |   |           |
                    |  v v   |      v   |5          |
                 +--------+  |    +--------+        |
                 |        |1 |    |        |--------+
                 |  Deg   |--+    |   Up   | 4
                 |        |<------|        |
                 +--------+      2+--------+
                                     |  ^
                                     |  |
                                     +--+
                                      12

                         Figure 5: LMP TE Link FSM

Lang et al                                                   [Page 25]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

8.3 Data Link FSM

   The data link FSM defines the states and logics of operation of a
   port or component link within an LMP TE link.  Operation of a data
   link is described in terms of FSM states and events.  Data-bearing
   links can either be in the active (transmitting) state, where Test
   messages are transmitted from them, or the passive (receiving)
   state, where Test messages are received through them.  For clarity,
   we define separate FSMs for the active/passive data-bearing links;
   however, we define a single set of data link states and events.

8.3.1 Data Link States

   Any data link can be in one of the states described below. Every
   state corresponds to a certain condition of the TE link.

   Down:          The data link has not been put in the resource pool.

   Test:          The data link is being tested.  An LMP Test message
                  is periodically sent through the link.

   PasvTest:      The data link is being checked for incoming test
                  messages.

   Up/Free:       The link has been successfully tested and is now put
                  in the pool of resources.  The link has not yet been
                  allocated to data traffic.

   Up/Allocated:  The link has been allocated for data traffic.

   Degraded:      The link was in the Up/Allocated state when the last
                  CC associated with data link's TE Link has gone down.
                  The link is put in the Degraded state, since it is
                  still being used for data LSP.

8.3.2 Data Link Events

   Data bearing link events are generated by the packet processing
   routines and by the FSMs of the associated control channel and the
   TE link.  Every event has its number and a symbolic name.
   Description of possible data link events is given below:

   1 :evCCUp:       CC has gone up.
   2 :evCCDown:     LMP neighbor connectivity is lost.  This indicates
                    the last LMP control channel has failed between
                    neighboring nodes.
   3 :evStartTst:   This is an external event that triggers the sending
                    of Test messages over the data bearing link.

   4 :evStartPsv:   This is an external event that triggers the
                    listening for Test messages over the data bearing
                    link.

Lang et al                                                   [Page 26]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001


   5 :evTestOK:     Link verification was successful and the link can
                    be used for path establishment.
                        (a) This event indicates the Link Verification
                            procedure (see Section 5) was successful
                            for this data link and a TestStatusSuccess
                            message was received over the control
                            channel.
                        (b) This event indicates the link is ready for
                            path establishment, but the Link
                            Verification procedure was not used.  For
                            in-band signaling of the control channel,
                            the control channel establishment may be
                            sufficient to verify the link.
   6 :evTestRcv:    Test message was received over the data port and a
                    TestStatusSuccess message is transmitted over the
                    control channel.
   7 :evTestFail:   Link verification returned negative results.  This
                    could be because (a) a ChannelStatusFailure message
                    was received, or (b) an EndVerifyAck message was
                    received without receiving a ChannelStatusSuccess
                    or ChannelStatusFailure message for the data link.
   8 :evPsvTestFail:Link verification returned negative results.  This
                    indicates that a Test message was not detected and
                    either (a) the VerifyDeadInterval has expired or
                    (b) an EndVerifyAck messages has been received and
                    the VerifyDeadInterval has not yet expired.
   9 :evLnkAlloc:   The data link has been allocated.
   10:evLnkDealloc: The data link has been deallocated.
   11:evTestRet:    A retransmission timer has expired and the Test
                    message is resent.

   11:evVerifyAbrt: The other side did not confirm it is ready to
                    perform link verification.
   12:evSummaryFail:The LinkSummary did not match for this data port.


















Lang et al                                                   [Page 27]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

8.3.3 Active Data Link FSM Description

   Figure 6 illustrates operation of the LMP active data link FSM in a
   form of FSM state transition diagram.

                             +------+
              +------------->|      |
              |   +--------->| Down |
              |   |     +----|      |
              |   |     |    +------+
              |   |     |5b   3|  ^
              |   |     |      |  |2,7
              |   |     |      v  |
              |   |     |    +------+
              |   |     |    |      |<-+
              |   |     |    | Test |  |11
              |   |     |    |      |--+
              |   |     |    +------+
              |   |     |     5a| 3^
              |   |     |       |  |
              |   |     |       v  |
              |   |2,12 |   +---------+
              |   |     +-->|         |
              |   |         | Up/Free |
              |   +---------|         |
              |             +---------+
              |                9| ^
              |                 | |
              |10               v |10
            +-----+  2      +---------+
            |     |<--------|         |
            | Deg |         |Up/Alloc |
            |     |-------->|         |
            +-----+  1      +---------+

                    Figure 6: Active LMP Data Link FSM

















Lang et al                                                   [Page 28]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

8.3.4 Passive Data Link FSM Description

   Figure 7 illustrates operation of the LMP passive data link FSM in a
   form of FSM state transition diagram.

                             +------+
              +------------->|      |
              |  +---------->| Down |
              |  |     +-----|      |
              |  |     |     +------+
              |  |     |5b    4|  ^
              |  |     |       |  |2
              |  |     |       v  |
              |  |     |    +----------+
              |  |     |    | PasvTest |
              |  |     |    +----------+
              |  |     |       6|  4^
              |  |     |        |   |
              |  |     |        v   |
              |  |2,12 |    +---------+
              |  |     +--->| Up/Free |
              |  |          |         |
              |  +----------|         |
              |             +---------+
              |                 9| ^
              |                  | |
              |10                v |10
            +-----+         +---------+
            |     |  2      |         |
            | Deg |<--------|Up/Alloc |
            |     |-------->|         |
            +-----+  1      +---------+

                    Figure 7: Passive LMP Data Link FSM



















Lang et al                                                   [Page 29]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

9. LMP Message Formats

   All LMP messages are IP encoded (except, in some cases, the Test
   message are limited by the transport mechanism for in-band
   messaging) with protocol number xxx - TBA (to be assigned) by IANA.

9.1. Common Header

   In addition to the standard IP header, all LMP messages (except, in
   some cases, the Test messages which are limited by the transport
   mechanism for in-band messaging) have the following common header:

    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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | Vers  |      (Reserved)       |    Flags      |    Msg Type   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          LMP Length           |           Checksum            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Local Channel/Link Id                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Vers: 4 bits

        Protocol version number.  This is version 1.

   Flags: 8 bits.  The following values are defined.  All other values
          are reserved.

        0x01: ControlChannelDown

        0x02: Node Reboot

               This bit is set to indicate the node has rebooted.  This
               flag may be reset to 0 when a Hello message is received
               with RcvSeqNum equal to the local TxSeqNum.

        0x04:  Link type

               If this bit is set, the link is numbered and the field
               carries an IP address; otherwise the link is unnumbered
               and the field carries a Link Id the associated IP
               address is learned through the configuration exchange.

        0x08: LMP-WDM Support

               When set, indicates that this node is willing and
               capable of receiving all the messages and objects
               described in [LMP-DWDM].




Lang et al                                                   [Page 30]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

        0x10: Authentication

               When set, this bit indicates that an authentication
               block is attached at the end of the LMP message.  See
               Sections 7 and 9.3 for more details.

   Msg Type: 8 bits.  The following values are defined.  All other
             values are reserved.

        1  = Config

        2  = ConfigAck

        3  = ConfigNack

        4  = Hello

        5  = BeginVerify

        6  = BeginVerifyAck

        7  = BeginVerifyNack

        8  = EndVerify

        9  = EndVerifyAck

        10 = Test

        11 = TestStatusSuccess

        12 = TestStatusFailure

        13 = TestStatusAck

        14 = LinkSummary

        15 = LinkSummaryAck

        16 = LinkSummaryNack

        17 = ChannelFail

        18 = ChannelFailAck

        19 = ChannelActive

        20 = ChannelActiveAck

        21 = ChannelDeactive

        22 = ChannelDeactiveAck

Lang et al                                                   [Page 31]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001


        All of the messages are sent over the control channel EXCEPT
        the Test message, which is sent over the data link that is
        being tested.

   LMP Length: 16 bits

        The total length of this LMP message in bytes, including the
        common header and any variable-length objects that follow.

   Checksum: 16 bits

        The standard IP checksum of the entire contents of the LMP
        message, starting with the LMP message header. This checksum is
        calculated as the 16-bit one's complement of the one's
        complement sum of all the 16-bit words in the packet. If the
        packet's length is not an integral number of 16-bit words, the
        packet is padded with a byte of zero before calculating the
        checksum.

   Local Channel/Link Id:  32 bits

        These Ids MUST be node-wide unique and non-zero.  For the
        Config, ConfigAck, ConfigNack, and Hello messages, this is the
        Local Control Channel Id (CCId) that identifies the control
        channel of the sender associated with the message.  For all
        other messages, this is the Local TE Link Id that identifies
        the sender's TE Link associated with the message.  The TE Link
        Id field MAY be zero in some messages when the TE Link has not
        yet been defined.

9.2 LMP TLV Format

   Many LMP messages are TLV based. The format of the LMP 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |N|          Type               |            Length             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                         (TLV Object)                        //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   N: 1 bit

        The N flag indicates if the object is a negotiable parameter
        (N=1) or a non-negotiable parameter (N=0).



Lang et al                                                   [Page 32]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   Type: 15 bits

        The Type field indicates the TLV type.

   Length: 16 bits

        The Length field indicates the length of the TLV Object in
        bytes.

9.3 Authentication

   When authentication is used for LMP, the authentication itself is
   appended to the LMP packet.  It is not considered to be a part of
   the LMP packet, but is transmitted in the same IP packet as 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                     LMP Common Header                       //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                        LMP Payload                          //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                    Authentication Block                     //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The authentication block looks 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      0        |   Auth Type   |    Key ID     | Auth Data Len |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                 Cryptographic Sequence Number                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                       MD5 Signature (16)                      |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Auth Type: 8 bits

              This defines the type of authentication used for LMP
              messages.  The following authentication types are
              defined, all other are reserved for future use:


Lang et al                                                   [Page 33]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

              0  No authentication
              1  Cryptographic authentication

   Key ID: 8 bits

              This field is defined only for cryptographic
              authentication.

   Auth Data Length: 8 bits
              This field contains the length of the data portion of the
              authentication block.

   LMP authentication is performed on a per control channel basis.  The
   packet authentication procedure is very similar to the one used in
   OSPF, including multiple key support, key management, etc. The
   details specific to LMP are defined below.

   Sending authenticated packets
   -----------------------------

   When a packet needs to be sent over a control channel and an
   authentication method is configured for it, the Authentication flag
   in the LMP header is set to 1, the LMP Length field is set to the
   length of the LMP packet only, not including the authentication
   block.

   1) The Checksum field in the LMP packet is set to zero (this will
      make the receiving side drop the packet if authentication is not
      supported).
   2) The LMP authentication header is filled out properly. The message
      digest is calculated over the LMP packet together with the LMP
      authentication header. The input to the message digest
      calculation consists of the LMP packet, the LMP authentication
      header, and the secret key. When using MD5 as the authentication
      algorithm, the message digest calculation proceeds as follows:

      (a) The authentication header is appended to the LMP packet.
      (b) The 16 byte MD5 key is appended after the LMP authentication
          header.
      (c) Trailing pad and length fields are added, as specified in
          [MD5].
      (d) The MD5 authentication algorithm is run over the
          concatenation of the LMP packet, authentication header,
          secret key, pad and length fields, producing a 16 byte
          message digest (see [MD5]).
      (e) The MD5 digest is written over the secret key (i.e., appended
          to the original authentication header).

   The authentication block is added to the IP packet right after the
   LMP packet, so IP packet length includes the length of both LMP
   packet and LMP authentication blocks.


Lang et al                                                   [Page 34]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   Receiving authenticated packets
   -------------------------------

   When an LMP packet with the Authentication flag set has been received
   on a control channel that is configured for authentication, it must
   be authenticated.  The value of the Authentication field MUST match
   the authentication type configured for the control channel (if any).

   If an LMP protocol packet is accepted as authentic, processing of the
   packet continues.  Packets that fail authentication are discarded.
   Note that the checksum field in the LMP packet header is not checked
   when the packet is authenticated.

   (1) Locate the receiving control channel's configured key having Key
       ID equal to that specified in the received LMP authentication
       block.  If the key is not found, or if the key is not valid for
       reception (i.e., current time does not fall into the key's
       active time frame), the LMP packet is discarded.
   (2) If the cryptographic sequence number found in the LMP
       authentication header is less than the cryptographic sequence
       number recorded in the control channel data structure, the LMP
       packet is discarded.
   (3) Verify the message digest in the data portion of the
       authentication block in the following steps:
       (a) The received digest is set aside.
       (b) A new digest is calculated, as specified in the previous
           section.
       (c) The calculated and received digests are compared.  If they
           do not match, the LMP packet is discarded.  If they do
           match, the LMP protocol packet is accepted as authentic, and
           the "cryptographic sequence number" in the control channel's
           data structure is set to the sequence number found in the
           packet's LMP header.

9.4 Parameter Negotiation

9.4.1 Config Message (MsgType = 1)

   The Config message is used in the control channel negotiation phase
   of LMP.  The contents of the Config message are built using TLV
   triplets.  TLVs can be either negotiable or non-negotiable
   (identified by the N flag in the TLV header).  Negotiable TLVs can
   be used to let the devices agree on certain values.  Non-negotiable
   TLVs are used for announcement of specific values that do not need
   or do not allow negotiation.  The format of the Config message is as
   follows:

   <Config Message> ::= <Common Header> <Config>





Lang et al                                                   [Page 35]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   The Config Object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Node ID                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         MessageId                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                      (Config TLVs)                          //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Node ID:  32 bits.

        This is the Node ID for the node.

   MessageId:  32 bits.

        When combined with the CCId in the LMP common header, the
        MessageId field uniquely identifies a message.  This value is
        incremented and only decreases when the value wraps.  This is
        used for message acknowledgment.

9.4.1.1 HelloConfig TLV

   The HelloConfig TLV is TLV Type=1 and 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |N|           1                 |               4               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         HelloInterval         |      HelloDeadInterval        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Length field of HelloConfig is always set to 4.

   N: 1 bit

        The N flag indicates if the parameter is negotiable (N=1) or
        non-negotiable (N=0).

   HelloInterval:  16 bits.

        Indicates how frequently the Hello packets will be sent and is
        measured in milliseconds (ms).





Lang et al                                                   [Page 36]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   HelloDeadInterval:  16 bits.

        If no Hello packets are received within the HelloDeadInterval,
        the control channel is assumed to have failed and is measured
        in milliseconds (ms).

9.4.2 ConfigAck Message (MsgType = 2)

   The ConfigAck message is used to indicate the receipt of the Config
   message and indicate agreement on all parameters.

   <ConfigAck Message> ::= <Common Header> <ConfigAck>

   The ConfigAck Object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Node ID                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         MessageId                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Rcv Node ID                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Rcv CCId                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Node ID:  32 bits.

        This is the Node ID for the node sending the ConfigAck message.

   MessageId:  32 bits.

        This is copied from the Config message being acknowledged.

   Rcv Node ID:  32 bits.

        This is copied from the Config message being acknowledged.

   Rcv CCId:  32 bits

        This is copied from the Common Header of the Config message
        being acknowledged.

9.4.3 ConfigNack Message (MsgType = 3)

   The ConfigNack message is used to indicate disagreement on non-
   negotiable parameters or propose other values for negotiable
   parameters.  Parameters where agreement was reached MUST NOT be
   included in the ConfigNack Object.  The format of the ConfigNack
   message is as follows:

Lang et al                                                   [Page 37]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001


   <ConfigNack Message> ::= <Common Header> <ConfigNack>

   The ConfigNack Object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Node ID                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         MessageId                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        Rcv Node ID                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Rcv CCId                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                      (Config TLVs)                          //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Node ID:  32 bits.

        This is the Node ID for the node.

   MessageId:  32 bits.

        This is copied from the Config message being negatively
        acknowledged.

   Rcv Node ID:  32 bits.

        This is copied from the Config message being negatively
        acknowledged.

   Rcv CCId:  32 bits

        This is copied from the Common Header of the Config message
        being negatively acknowledged.

   The Config TLVs in the ConfigNack message MUST include acceptable
   values for all negotiable parameters.  If the ConfigNack includes
   Config TLVs for non-negotiable parameters, they MUST be copied from
   the Config TLVs received in the Config message.

   If the ConfigNack message is received and only includes negotiable
   parameters, then a new Config message SHOULD be sent.  The values
   received in the new Config message SHOULD take into account the
   acceptable parameters included in the ConfigNack message.




Lang et al                                                   [Page 38]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

9.5 Hello Message (MsgType = 4)

   The format of the Hello message is as follows:

   <Hello Message> ::= <Common Header> <Hello>.

   The Hello object 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           TxSeqNum                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           RcvSeqNum                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   TxSeqNum:  32 bits

        This is the current sequence number for this Hello message.
        This sequence number will be incremented when the sequence
        number is reflected in the RcvSeqNum of a Hello packet that is
        received over the control channel.

        TxSeqNum=0 is not allowed.

        TxSeqNum=1 is reserved to indicate that the control channel has
        booted or rebooted.

   RcvSeqNum:  32 bits

        This is the sequence number of the last Hello message received
        over the control channel.  RcvSeqNum=0 is reserved to indicate
        that a Hello message has not yet been received.

9.6 Link Verification

9.6.1 BeginVerify Message (MsgType = 5)

   The BeginVerify message is sent over the control channel and is used
   to initiate the link verification process.  The format is as
   follows:

   <BeginVerify Message> ::= <Common Header> <BeginVerify>










Lang et al                                                   [Page 39]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   The BeginVerify object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    Flags                      |         VerifyInterval        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           MessageId                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Remote TE Link Id                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Number of Data Links                    |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |              EncType          |  Verify Transport Mechanism   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                            BitRate                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          Wavelength                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


   Flags:  16 bits

        The following flags are defined:

        0x01 Verify all Links
                If this bit is set, the verification process checks all
                unallocated links; else it only verifies new ports or
                component links that are to be added to this TE link.
        0x02 Data Link Type
                If set, the data links to be verified are ports,
                otherwise they are component links

   VerifyInterval:  16 bits

        This is the interval between successive Test messages and is
        measured in milliseconds (ms).

   MessageId:  32 bits

        When combined with the Local TE Link Id in the common header of
        the received packet, the MessageId field uniquely identifies a
        message.  This value is incremented and only decreases when the
        value wraps.  This is used for message acknowledgment in the
        BeginVerifyAck and BeginVerifyNack messages.

   Remote TE Link Id:  32 bits

        This identifies the TE Link Id of the remote node, which may be
        numbered or unnumbered (see Flags in the LMP common header),
        for the ports or component links that are being verified. If
        this value is set to 0, the local node has no knowledge of the

Lang et al                                                   [Page 40]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

        remote TE Link Id.  It is expected that when verifying an
        unnumbered TE Link for the first time this will be set to 0.

   Number of Data Links:  32 bits

        This is the number of data links that will be verified.

   EncType:  16 bits

        This is the encoding type of the data link and is required for
        the purpose of testing where the data links are not required to
        be the same encoding type as the control channel.  The defined
        EncType values are consistent with the Link Encoding Type
        values of [OSPF-GEN] and [ISIS-GEN].

   Verify Transport Mechanism:  16 bits

        This defines the transport mechanism for the Test Messages. The
        scope of this bit mask is restricted to each link encoding
        type. The local node will set the bits corresponding to the
        various mechanisms it can support for transmitting LMP test
        messages. The receiver chooses the appropriate mechanism in the
        BeginVerifyAck message.

        For SONET/SDH Encoding Type, the following flags are defined:
        0x01 Capable of communicating using J0 overhead bytes.
                Test Message is transmitted using the J0 bytes.
        0x02 Capable of communicating using Section DCC bytes.
                Test Message is transmitted using the DCC Section
                Overhead bytes with an HDLC framing format.
        0x04 Capable of communicating using Line DCC bytes.
                Test Message is transmitted using the DCC Line Overhead
                bytes with an HDLC framing format.
        0x08 Capable of communicating using POS.
                Test Message is transmitted using Packet over SONET
                framing using the encoding type specified in the
                EncType field.

        For GigE Encoding Type, the following flags are defined: TBD

        For 10GigE Encoding Type, the following flags are defined: TBD

   BitRate:  32 bits

        This is the bit rate of the data link over which the Test
        messages will be transmitted and is expressed in bytes per
        second.

   Wavelength:  32 bits

        When a data link is assigned to a port or component link that
        is capable of transmitting multiple wavelengths (e.g., a fiber

Lang et al                                                   [Page 41]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

        or waveband-capable port), it is essential to know which
        wavelength the test messages will be transmitted over.  This
        value corresponds to the wavelength at which the Test messages
        will be transmitted over and is measured in nanometers (nm).
        If there is no ambiguity as to the wavelength over which the
        message will be sent, than this value SHOULD be set to 0.

9.6.2 BeginVerifyAck Message (MsgType = 6)

   When a BeginVerify message is received and Test messages are ready
   to be processed, a BeginVerifyAck message MUST be transmitted.

   <BeginVerifyAck Message> ::= <Common Header> <BeginVerifyAck>

   The BeginVerifyAck object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Remote TE Link Id                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      VerifyDeadInterval       |   Verify Transport Response   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          VerfifyId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   MessageId:  32 bits

        This is copied from the BeginVerify message being acknowledged.

   Remote TE Link Id: 32 bits

        This is copied from the Common Header of the BeginVerify
        message being acknowledged.

   VerifyDeadInterval:  16 bits

        If a Test message is not detected within the
        VerifyDeadInterval, then a node will send the TestStatusFailure
        message for that data link.

   Verification Transport Response:  16 bits

        The recipient of the BeginVerify message (and the future
        recipient of the TEST messages) chooses the transport mechanism
        from the various types that are offered by the transmitter of
        the Test messages.  One and only one bit MUST be set in the
        verification transport response.




Lang et al                                                   [Page 42]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   VerifyId:  32 bits

        This is used to differentiate Test messages from different TE
        links and/or LMP peers.  This is a node-unique value that is
        assigned by the recipient of the BeginVerify message.

9.6.3 BeginVerifyNack Message (MsgType = 7)

   If a BeginVerify message is received and a node is unwilling or
   unable to begin the Verification procedure, a BeginVerifyNack
   message MUST be transmitted.

   <BeginVerifyNack Message> ::= <Common Header> <BeginVerifyNack>

   The BeginVerifyNack object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Remote TE Link Id                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |          Error Code           |        (Reserved)             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        This is copied from the BeginVerify message being negatively
        acknowledged.

   Remote TE Link Id: 32 bits

        This is copied from the Common Header of the BeginVerify
        message being negatively acknowledged.

   Error Code: 16 bits

        The following values are defined:
        1 = Link Verification Procedure not supported for this TE Link.
        2 = Unwilling to verify at this time
        3 = TE Link Id configuration error
        4 = Unsupported verification transport mechanism

   If a BeginVerifyNack message is received with Error Code 2, the node
   that originated the BeginVerify SHOULD schedule a BeginVerify
   retransmission after Rf seconds, where Rf is a locally defined
   parameter.





Lang et al                                                   [Page 43]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

9.6.4 EndVerify Message (MsgType = 8)

   The EndVerify message is sent over the control channel and is used
   to terminate the link verification process.  The EndVerify message
   may be sent at any time a node desires to end the Verify procedure.
   The format is as follows:

   <EndVerify Message> ::= <Common Header> <EndVerify>

   The EndVerify object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           MessageId                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           VerifyId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        When combined with the Local TE Link Id in the common header of
        the received packet, the MessageId field uniquely identifies a
        message.  This value is incremented and only decreases when the
        value wraps.  This is used for message acknowledgement in the
        EndVerifyAck message.

   VerifyId:  32 bits

        This is the VerifyId corresponding to the link verification
        process that is being terminated.

9.6.5 EndVerifyAck Message (MsgType =9)

   The EndVerifyAck message is sent over the control channel and is
   used to acknowledge the termination of the link verification
   process.  The format is as follows:

   <EndVerifyAck Message> ::= <Common Header> <EndVerifyAck>

   The EndVerifyAck object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Remote TE Link Id                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+




Lang et al                                                   [Page 44]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   MessageId:  32 bits

        This is copied from the EndVerify message being acknowledged.

   Remote TE Link Id: 32 bits

        This is copied from the Common Header of the EndVerify message
        being acknowledged.

9.6.6 Test Message (MsgType = 10)

   The Test message is transmitted over the data link and is used to
   verify its physical connectivity. Unless explicitly stated below,
   this is transmitted as an IP packet with payload format as follows:

   <Test Message> ::= <Common Header> <Test>

   The Test object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           VerifyId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                         Interface Id                          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   VerifyId:  32 bits

        The VerifyId identifies the link verification procedure with
        which the data link verification is associated.

   Interface Id:  32 bits

        The Interface Id identifies the data link (either port or
        component link) over which this message is sent. A valid
        Interface Id MUST be nonzero.

   Note that this message is sent over a data link and NOT over the
   control channel.

9.6.7 TestStatusSuccess Message (MsgType = 11)

   The TestStatusSuccess message is transmitted over the control
   channel and is used to transmit the mapping between the local
   Interface Id and the Interface Id that was received in the Test
   message.

   <TestStatus Message> ::= <Common Header> <TestStatusSuccess>




Lang et al                                                   [Page 45]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   The TestStatusSuccess object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Received Interface Id                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Local Interface Id                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          VerifyId                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        When combined with the Local TE Link Id in the common header of
        the received packet, the MessageId field uniquely identifies a
        message.  This value is incremented and only decreases when the
        value wraps.  This is used for message acknowledgement in the
        TestStatusAck message.

   Received Interface Id:  32 bits

        This is the value of the Interface Id that was received in the
        Test message.  A valid Interface Id MUST be nonzero.

   Local Interface Id:  32 bits

        This is the local value of the Interface Id and MUST be
        nonzero.

   VerifyId:  32 bits

        The VerifyId identifies the link verification procedure with
        which the data link is associated.

9.6.8 TestStatusFailure Message (MsgType = 12)

   The TestStatusFailure message is transmitted over the control
   channel and is used to indicate that the Test message was not
   received.

   <TestStatus Message> ::= <Common Header> <TestStatusFailure>









Lang et al                                                   [Page 46]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   The TestStatusFailure object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          VerifyId                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        When combined with the Local TE Link Id in the common header of
        the received packet, the MessageId field uniquely identifies a
        message.  This value is incremented and only decreases when the
        value wraps.  This is used for message acknowledgement in the
        TestStatusAck message.

   VerifyId:  32 bits

        The VerifyId identifies the link verification procedure for
        which the timer has expired and no TEST messages have been
        received.

9.6.9 TestStatusAck Message (MsgType = 13)

   The TestStatusAck message is used to acknowledge receipt of the
   TestStatusSuccess or TestStatusFailure messages.

   <TestStatusAck Message> ::= <Common Header> <TestStatusAck>

   The TestStatusAck object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Remote TE Link Id                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        This is copied from the TestStatusSuccess or TestStatusFailure
        message being acknowledged.

   Remote TE Link Id: 32 bits

        This is copied from the Common Header of the TestStatusSuccess
        or TestStatusFailure message being acknowledged.



Lang et al                                                   [Page 47]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

9.7 Link Summary Messages

9.7.1 LinkSummary Message (MsgType = 14)

   The LinkSummary message is used to synchronize the Interface Ids and
   correlate the properties of the TE link.  The format of the
   LinkSummary message is as follows:

   <LinkSummary Message> ::= <Common Header> <LinkSummary>

   The LinkSummary Object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                     (LinkSummary TLVs)                      //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        When combined with the Local TE Link Id in the common header of
        the received packet, the MessageId field uniquely identifies a
        message.  This value is incremented and only decreases when the
        value wraps.  This is used for message acknowledgement in the
        LinkSummaryAck and LinkSummaryNack messages.

9.7.1.1 TE Link TLV

   The TE Link TLV is TLV Type=3 and 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|           3                 |               8               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Flags     |  Link Mux Cap |           (Reserved)          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Remote TE Link Id                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The TE Link TLV is non-negotiable.








Lang et al                                                   [Page 48]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   Flags: 8 bits
        The following flags are defined.  All other values are
        reserved.

        0x01 Fault Management Supported.

        0x02 Link Verification Supported.

   Link Mux Cap: 8 bits

        This is used to identify the associated
        multiplexing/demultiplexing capability of the TE link.  See
        [LSP-HIER].

   Remote TE Link Id: 32 bits

        This identifies the TE link of the remote node, which may be
        numbered or unnumbered (see Flags in Common Header). If the
        local node has no knowledge of the Remote TE Link Id, this
        value MUST be set to 0.

9.7.1.2 Data-link TLV

   The Data Link TLV is TLV Type=4 and 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|           4                 |            Length             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     Flags     |   Link Type   |           (Reserved)          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                    Local Interface Id                         |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                     Remote Interface Id                       |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                   (Data-link sub-TLVs)                      //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Data Link TLV is non-negotiable.

   Length: 16 bits

   The Length of the Primary Data Link TLV including all data-link sub-
   TLVs.






Lang et al                                                   [Page 49]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   Flags: 8 bits

        The following flags are defined.  All other values are
        reserved.

        0x01 Interface Type: If set, the data link is a port,
                              otherwise it is a component link.
        0x02 Allocated Link: If set, the data link is currently
                              allocated for user traffic.

   Link Type: 8 bits

        This is used to identify the encoding type of the data link.
        See [OSPF-GEN] or [ISIS-TE].

   Remote Interface Id:  32 bits

        This is the value of the corresponding Interface Id.  If Link
        Verification was used, then this is the value that was either
        (a) received in the Test message, or (b) received in the
        TestStatusSuccess message.

9.7.1.3 Data Link Sub-TLV

   The data link sub-TLV is used to provide characteristics of the
   data-bearing links.  Currently, there are no data link sub-TLVs
   defined.

9.7.2 LinkSummaryAck Message (MsgType = 15)

   The LinkSummaryAck message is used to indicate agreement on the
   Interface Id synchronization and acceptance/agreement on all the
   link parameters. It is on the reception of this message that the
   local node makes the TE Link Id associations.

   <LinkSummaryAck Message> ::= <Common Header> <LinkSummaryAck>

   The LinkSummaryAck object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Remote TE Link Id                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        This is copied from the LinkSummary message being acknowledged.



Lang et al                                                   [Page 50]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   Remote TE Link Id: 32 bits

        This is copied from the Common Header of the LinkSummary
        message being acknowledged.

9.7.3 LinkSummaryNack Message (MsgType = 16)

   The LinkSummaryNack message is used to indicate disagreement on non-
   negotiated parameters or propose other values for negotiable
   parameters.  Parameters where agreement was reached MUST NOT be
   included in the LinkSummaryNack Object.

   <LinkSummaryNack Message> ::= <Common Header> <LinkSummaryNack>

   The LinkSummaryNack object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Remote TE Link Id                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                     (LinkSummary TLVs)                      //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        This is copied from the LinkSummary message being negatively
        acknowledged.

   Remote TE Link Id: 32 bits

        This is copied from the Common Header of the LinkSummary
        message being negatively acknowledged.

   The LinkSummary TLVs MUST include acceptable values for all
   negotiable parameters.  If the LinkSummaryNack includes LinkSummary
   TLVs for non-negotiable parameters, they MUST be copied from the
   LinkSummary TLVs received in the LinkSummary message.

   If the LinkSummaryNack message is received and only includes
   negotiable parameters, then a new LinkSummary message SHOULD be
   sent.  The values received in the new LinkSummary message SHOULD
   take into account the acceptable parameters included in the
   LinkSummaryNack message.





Lang et al                                                   [Page 51]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

9.8 Fault Management Messages

9.8.1 ChannelFail Message (MsgType = 17)

   The ChannelFail message is sent over the control channel and is used
   to notify a neighboring node that a data link (port or component
   link) failure has been detected.  A neighboring node that receives a
   ChannelFail message MUST respond with a ChannelFailAck message.  The
   format is as follows:

   <ChannelFail Message> ::= <Common Header> <ChannelFail>

   The format of the ChannelFail object 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           MessageId                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                         (Failure TLV)                       //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        When combined with the Local TE Link Id in the common header of
        the received packet, the MessageId field uniquely identifies a
        message.  This value is incremented and only decreases when the
        value wraps.  This is used for message acknowledgement in the
        ChannelFailAck message.

   If the Failure TLV is not included, the ChannelFail message
   indicates the entire TE Link has failed.

9.8.1.2 Failed Channel TLV

   The Failed Channel TLV is TLV Type=5.  This TLV contains one or more
   Failed Channels of a TE link and has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|             5               |             Length            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                    (Local Interface Ids)                    //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Failed Channel TLV is non-negotiable.


Lang et al                                                   [Page 52]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   Length:  16 bits

        The Length is in bytes (see LMP TLV format).

   Local Interface Id:  32 bits

        This is the local Interface Id (either Port Id or Component
        Interface Id) of the data link that has failed.  This is within
        the scope of the TE Link Id.  Multiple Local Interface Ids may
        be placed into a single Failed Channel TLV.

9.8.2 ChannelFailAck Message (MsgType = 18)

   The ChannelFailAck message is used to indicate that all of the
   reported failures in the ChannelFail message also have failures on
   the corresponding input channels.  The format is as follows:

   <ChannelFailureAck Message> ::= <Common Header> <ChannelFailureAck>

   The ChannelFailureAck object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Remote TE Link Id                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        This is copied from the ChannelFail message being acknowledged.

   Remote TE Link Id: 32 bits

        This is copied from the Common Header of the ChannelFail
        message being acknowledged.

9.8.4 ChannelActive Message (MsgType = 19)

   The ChannelActive message is sent over the control channel and is
   used to notify a neighboring node that a data link (port or
   component link) is now carrying user data traffic.  A
   ChannelActiveAck message MUST be sent to acknowledge receipt of the
   ChannelActive message.  The format is as follows:

   <ChannelActive Message> ::= <Common Header> <ChannelActive>






Lang et al                                                   [Page 53]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   The format of the ChannelActive object 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           MessageId                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                        (Active TLV)                         //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        When combined with the Local TE Link Id in the common header of
        the received packet, the MessageId field uniquely identifies a
        message.  This value is incremented and only decreases when the
        value wraps.  This is used for message acknowledgement in the
        ChannelActiveAck message.

9.8.4.1 Active Channel TLV

   The Active Channel TLV is TLV Type=6.  This TLV contains one or more
   Active Channels of a TE link and has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|             6               |             Length            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                    (Local Interface Ids)                    //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   The Active Channel TLV is non-negotiable.

   Length:  16 bits

        The Length is in bytes (see LMP TLV format).

   Local Interface Id:  32 bits

        This is the local Interface Id (either Port Id or Component
        Interface Id) of the data link that has become active.  This is
        within the scope of the TE Link Id.  Multiple Local Interface
        Ids may be placed into a single Active Channel TLV.






Lang et al                                                   [Page 54]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

9.8.5 ChannelActiveAck Message (MsgType = 20)

   The ChannelActiveAck message is used to acknowledge receipt of the
   ChannelActive message.  The format is as follows:

   <ChannelActiveAck Message> ::= <Common Header> <ChannelActiveAck>

   The ChannelActiveAck object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Remote TE Link Id                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        This is copied from the ChannelActive message being
        acknowledged.

   Remote TE Link Id: 32 bits

        This is copied from the Common Header of the ChannelActive
        message being acknowledged.

9.8.4 ChannelDeactive Message (MsgType = 21)

   The ChannelDeactive message is sent over the control channel and is
   used to notify a neighboring node that a data link (port or
   component link) should be deactivated.  A ChannelDeactiveAck message
   MUST be sent to acknowledge receipt of the ChannelDeactive message.
   The format is as follows:

   <ChannelDeactive Message> ::= <Common Header> <ChannelDeactive>

   The format of the ChannelDeactive object 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
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                           MessageId                           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   //                        (Active TLV)                         //
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+





Lang et al                                                   [Page 55]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001

   MessageId:  32 bits

        When combined with the Local TE Link Id in the common header of
        the received packet, the MessageId field uniquely identifies a
        message.  This value is incremented and only decreases when the
        value wraps.  This is used for message acknowledgement in the
        ChannelDeactiveAck message.

9.8.5 ChannelDeactiveAck Message (MsgType = 22)

   The ChannelDeactiveAck message is used to acknowledge receipt of the
   ChannelDeactive message.  The format is as follows:

   <ChannelDeactiveAck Message> ::= <Common Header><ChannelDeactiveAck>

   The ChannelDeactiveAck object has the following format:

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                          MessageId                            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                      Remote TE Link Id                        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   MessageId:  32 bits

        This is copied from the ChannelActive message being
        acknowledged.

   Remote TE Link Id: 32 bits

        This is copied from the Common Header of the ChannelActive
        message being acknowledged.

10. Security Considerations

   LMP exchanges may be authenticated using the Cryptographic
   authentication option.  MD5 is currently the only message digest
   algorithm specified.

11. References

   [RFC2026]   Bradner, S., "The Internet Standards Process -- Revision
               3," BCP 9, RFC 2026, October 1996.
   [LAMBDA]    Awduche, D. O., Rekhter, Y., Drake, J., Coltun, R.,
               "Multi-Protocol Lambda Switching: Combining MPLS Traffic
               Engineering Control with Optical Crossconnects,"
               Internet Draft, draft-awduche-mpls-te-optical-03.txt,
               (work in progress), April 2001.



Lang et al                                                   [Page 56]


Internet Draft       draft-ietf-ccamp-lmp-00.txt            July 2001


   [BUNDLE]    Kompella, K., Rekhter, Y., Berger, L., ôLink Bundling in
               MPLS Traffic Engineering,ö Internet Draft, draft-
               kompella-mpls-bundle-05.txt, (work in progress), February
               2001.
   [RSVP-TE]   Awduche, D. O., Berger, L., Gan, D.-H., Li, T.,
               Srinivasan, V., Swallow, G., "Extensions to RSVP for LSP
               Tunnels," Internet Draft, draft-ietf-mpls-rsvp-lsp-
               tunnel-08.txt, (work in progress), February 2001.
   [CR-LDP]    Jamoussi, B., et al, "Constraint-Based LSP Setup using
               LDP," Internet Draft, draft-ietf-mpls-cr-ldp-05.txt,
               (work in progress), September 1999.
   [OSPF-TE]   Katz, D., Yeung, D., Kompella, K., "Traffic Engineering
               Extensions to OSPF," Internet Draft, draft-katz-yeung-
               ospf-traffic-04.txt, (work in progress), February 2001.
   [ISIS-TE]   Li, T., Smit, H., "IS-IS extensions for Traffic
               Engineering," Internet Draft,draft-ietf-isis-traffic-
               02.txt, (work in progress), September 2000.
   [OSPF]      Moy, J., "OSPF Version 2," RFC 2328, April 1998.
   [LMP-DWDM]  Fredette, A., Snyder, E., Shantigram, J., et al, ôLink
               Management Protocol (LMP) for WDM Transmission Systems,ö
               Internet Draft, draft-fredette-lmp-wdm-01.txt, (work in
               progress), March 2001.
   [MD5]       Rivest, R., "The MD5 Message-Digest Algorithm," RFC
               1321, April 1992.
   [OSPF-GEN]  Kompella, K., Rekhter, Y., Banerjee, A., et al, "OSPF
               Extensions in Support of Generalized MPLS," Internet
               Draft, draft-kompella-ospf-gmpls-extensions-01.txt,
               (work in progress), February 2001.
   [ISIS-GEN]  Kompella, K., Rekhter, Y., Banerjee, A., et al, "IS-IS
               Extensions in Support of Generalized MPLS," Internet
               Draft, draft-ietf-gmpls-extensions-02.txt, (work in
               progress), February 2001.
   [LSP-HIER]  Kompella, K. and Rekhter, Y., ôLSP Hierarchy with MPLS
               TE,ö Internet Draft, draft-ietf-mpls-lsp-hierarchy-
               02.txt, (work in progress), February 2001.

















Lang et al                                                   [Page 57]


12. Acknowledgments

   The authors would like to thank Ayan Banerjee, George Swallow, Andre
   Fredette, Adrian Farrel, and Vinay Ravuri for their insightful
   comments and suggestions.  We would also like to thank John Yu,
   Suresh Katukam, and Greg Bernstein for their helpful suggestions for
   the in-band control channel applicability.

13. Author's Addresses

   Jonathan P. Lang                        Krishna Mitra
   Calient Networks                        Calient Networks
   25 Castilian Drive                      5853 Rue Ferrari
   Goleta, CA 93117                        San Jose, CA 95138
   Email: jplang@calient.net               email: krishna@calient.net

   John Drake                              Kireeti Kompella
   Calient Networks                        Juniper Networks, Inc.
   5853 Rue Ferrari                        385 Ravendale Drive
   San Jose, CA 95138                      Mountain View, CA 94043
   email: jdrake@calient.net               email: kireeti@juniper.net

   Yakov Rekhter                           Lou Berger
   Juniper Networks, Inc.                  Movaz Networks
   385 Ravendale Drive                     email: lberger@movaz.com
   Mountain View, CA 94043
   email: yakov@juniper.net

   Debanjan Saha                           Debashis Basak
   Tellium Optical Systems                 Accelight Networks
   2 Crescent Place                        70 Abele Road, Suite 1201
   Oceanport, NJ 07757-0901                Bridgeville, PA 15017-3470
   email:dsaha@tellium.com                 email: dbasak@accelight.com


   Hal Sandick                             Alex Zinin
   Nortel Networks                         Cisco Systems
   email: hsandick@nortelnetworks.com      150 W. Tasman Dr.
                                           San Jose, CA 95134
                                           email: azinin@cisco.com
   Bala Rajagopalan
   Tellium Optical Systems
   2 Crescent Place
   Oceanport, NJ 07757-0901
   email: braja@tellium.com








Lang/Mitra et al                                              [Page 1]


Html markup produced by rfcmarkup 1.129b, available from https://tools.ietf.org/tools/rfcmarkup/