NSP generation of the PCInitiate message

Procedure

  1. When the PCEP session is established from the PCC to PCE, the PCC and PCE exchange the OPEN object and both set the LSP-INSTANTIATION CAPABILITY flag (I flag), in the STATEFUL-PCE-CAPABILITY TLV flag field.
  2. The operator, using the north-bound REST interface, the NSD or another interface, requests the NSP to initiate an LSP.
    The following parameters are specified:

    • source address

    • destination address

    • LSP type (SR-TE)

    • bandwidth value

    • include/exclude admin-group constraints

    • optional PCE path profile ID for the path computation at the PCE

    • optional PCE-initiated LSP template ID for use by the PCC to complete the instantiation of the LSP

  3. The NSP crafts the PCInitiate message and sends it to the PCC using PCEP.
    The message contains the:
    • LSP object with PLSP-ID=0
    • SRP object
    • ENDPOINTS object
    • computed SR-ERO (SR-TE) object
    • list of LSP attributes
      • BANDWIDTH object
      • one or more METRIC objects
      • LSPA object
    The LSP path name is inserted into the Symbolic Path Name TLV in the LSP object.
  4. The PCE-initiated LSP template ID to be used at the PCC, if any, is included in the PATH-PROFILE-ID TLV of the Path Profile object or the Association ID in an ASSOCIATION object of type Policy.
    The profile ID matches the PCE-initiated LSP template ID at the PCC and is not the same as the path profile ID used on the PCE to compute the path of this PCE-initiated LSP.
    Note: The range of the LSP template ID is 32-bits, but the range of the Association Group ID is only 16 bits. Therefore, the range of Association Group IDs that can be used to reference a template ID is limited to the bottom 16 bits of the 32-bit template ID range.
  5. The path profile ID is used on the PCE to compute the path of this PCE-initiated LSP.
Parent topic: LSP instantiation using PCEP