rfc3212.txt

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   If, after possible Traffic Parameter negotiation, an LSR can support
   the CR-LSP Traffic Parameters then the LSR MUST reserve the
   corresponding resources for the CR-LSP.

   If, after possible Traffic Parameter negotiation, an LSR cannot
   support the CR-LSP Traffic Parameters then the LSR MUST send a
   Notification Message that contains the "Resource Unavailable" status
   code.

4.3.2.2 Label Mapping Message

   If an LSR receives an incorrectly encoded Traffic Parameters TLV in
   which the value of PDR is less than the value of CDR then it MUST
   send a Label Release message containing the Status code "Traffic
   Parameters Unavailable" to the LSR from which it received the
   erroneous message.  In addition, the LSP should send a Notification
   Message upstream with the status code 'Label Request Aborted'.

   If the negotiation flag was set in the label request message, the
   egress LSR MUST include the (possibly negotiated) Traffic Parameters
   and Weight in the Label Mapping message.

   The Traffic Parameters and the Weight in a Label Mapping message MUST
   be forwarded unchanged.



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   An LSR SHOULD adjust the resources that it reserved for a CR-LSP when
   it receives a Label Mapping Message if the Traffic Parameters differ
   from those in the corresponding Label Request Message.

4.3.2.3 Notification Message

   If an LSR receives a Notification Message for a CR-LSP, it SHOULD
   release any resources that it possibly had reserved for the CR-LSP.
   In addition, on receiving a Notification Message from a Downstream
   LSR that is associated with a Label Request from an upstream LSR, the
   local LSR MUST propagate the Notification message using the
   procedures in [1].  Further the F bit MUST be set.

4.4 Preemption TLV

   The default value of the setup and holding priorities should be in
   the middle of the range (e.g., 4) so that this feature can be turned
   on gradually in an operational network by increasing or decreasing
   the priority starting at the middle of the range.

   Since the Preemption TLV is an optional TLV, LSPs that are setup
   without an explicitly signaled preemption TLV SHOULD be treated as
   LSPs with the default setup and holding priorities (e.g., 4).

   When an established LSP is preempted, the LSR that initiates the
   preemption sends a Withdraw Message upstream and a Release Message
   downstream.

   When an LSP in the process of being established (outstanding Label
   Request without getting a Label Mapping back) is preempted, the LSR
   that initiates the preemption, sends a Notification Message upstream
   and an Abort Message downstream.

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|0|     Type = 0x0820         |      Length = 4               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |  SetPrio      | HoldPrio      |      Reserved                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type
         A fourteen-bit field carrying the value of the Preemption-TLV
         Type = 0x0820.

   Length
         Specifies the length of the value field in bytes = 4.




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   Reserved
         Zero on transmission.  Ignored on receipt.

   SetPrio
         A SetupPriority of value zero (0) is the priority assigned to
         the most important path.  It is referred to as the highest
         priority.  Seven (7) is the priority for the least important
         path.  The higher the setup priority, the more paths CR-LDP can
         bump to set up the path.  The default value should be 4.

   HoldPrio
         A HoldingPriority of value zero (0) is the priority assigned to
         the most important path.  It is referred to as the highest
         priority.  Seven (7) is the priority for the least important
         path.  The default value should be 4.
         The higher the holding priority, the less likely it is for CR-
         LDP to reallocate its bandwidth to a new path.

4.5 LSPID TLV

   LSPID is a unique identifier of a CR-LSP within an MPLS network.

   The LSPID is composed of the ingress LSR Router ID (or any of its
   own Ipv4 addresses) and a Locally unique CR-LSP ID to that LSR.

   The LSPID is useful in network management, in CR-LSP repair, and in
   using an already established CR-LSP as a hop in an ER-TLV.

   An "action indicator flag" is carried in the LSPID TLV.  This "action
   indicator flag" indicates explicitly the action that should be taken
   if the LSP already exists on the LSR receiving the message.

   After a CR-LSP is set up, its bandwidth reservation may need to be
   changed by the network operator, due to the new requirements for the
   traffic carried on that CR-LSP.  The "action indicator flag" is used
   indicate the need to modify the bandwidth and possibly other
   parameters of an established CR-LSP without service interruption.
   This feature has application in dynamic network resources management
   where traffic of different priorities and service classes is
   involved.

   The procedure for the code point "modify" is defined in [8].  The
   procedures for other flags are FFS.








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   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|0|       Type = 0x0821       |      Length = 4               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |       Reserved        |ActFlg |      Local CR-LSP ID          |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                       Ingress LSR Router ID                   |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type
         A fourteen-bit field carrying the value of the LSPID-TLV
         Type = 0x0821.

   Length
         Specifies the length of the value field in bytes = 4.

   ActFlg
         Action Indicator Flag: A 4-bit field that indicates explicitly
         the action that should be taken if the LSP already exists on
         the LSR receiving the message.  A set of indicator code points
         is proposed as follows:

               0000: indicates initial LSP setup
               0001: indicates modify LSP

   Reserved
         Zero on transmission.  Ignored on receipt.

   Local CR-LSP ID
         The Local LSP ID is an identifier of the CR-LSP locally unique
         within the Ingress LSR originating the CR-LSP.

   Ingress LSR Router ID
         An LSR may use any of its own IPv4 addresses in this field.

4.6 Resource Class (Color) TLV

   The Resource Class as defined in [3] is used to specify which links
   are acceptable by this CR-LSP.  This information allows for the
   network's topology to be pruned.










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   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|0|         Type = 0x0822     |      Length = 4               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                             RsCls                             |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type
         A fourteen-bit field carrying the value of the ResCls-TLV
         Type = 0x0822.

   Length
         Specifies the length of the value field in bytes = 4.

   RsCls
         The Resource Class bit mask indicating which of the 32
         "administrative groups" or "colors" of links the CR-LSP can
         traverse.

4.7 ER-Hop semantics

4.7.1. ER-Hop 1: The IPv4 prefix

   The abstract node represented by this ER-Hop is the set of nodes,
   which have an IP address, which lies within this prefix.  Note that a
   prefix length of 32 indicates a single IPv4 node.

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|0|         Type = 0x0801     |      Length = 8               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |L|      Reserved                               |    PreLen     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                    IPv4 Address (4 bytes)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type
         A fourteen-bit field carrying the value of the ER-Hop 1, IPv4
         Address, Type = 0x0801

   Length
         Specifies the length of the value field in bytes = 8.

   L Bit
         Set to indicate Loose hop.
         Cleared to indicate a strict hop.



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   Reserved
         Zero on transmission.  Ignored on receipt.

   PreLen
         Prefix Length 1-32

   IP Address
         A four-byte field indicating the IP Address.

4.7.2. ER-Hop 2: The IPv6 address

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|0|          0x0802           |      Length = 20              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |L|             Reserved                        |    PreLen     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  IPV6 address                                 |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  IPV6 address (continued)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  IPV6 address (continued)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                  IPV6 address (continued)                     |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type
         A fourteen-bit field carrying the value of the ER-Hop 2, IPv6
         Address, Type = 0x0802

   Length
         Specifies the length of the value field in bytes = 20.

   L Bit
         Set to indicate Loose hop.
         Cleared to indicate a strict hop.

   Reserved
         Zero on transmission.  Ignored on receipt.

   PreLen
         Prefix Length 1-128

   IPv6 address
         A 128-bit unicast host address.





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4.7.3. ER-Hop 3:  The autonomous system number

   The abstract node represented by this ER-Hop is the set of nodes
   belonging to the autonomous system.

   0                   1                   2                   3
   0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |0|0|          0x0803           |      Length = 4               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |L|          Reserved           |                AS Number      |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Type