As per [RFC 8697
], LSPs are associated with other LSPs with which they interact by adding them to a common association group. Grouping can also be used to define the association between LSPs and the policies associated with them. As described in [RFC 8697
], the association group is uniquely identified by the combination of the following fields in the ASSOCIATION object: Association Type, Association ID, Association Source, and (if present) Global Association Source or Extended Association ID. This document defines a new Association Type called "Policy Association" with value 3 based on the generic ASSOCIATION object. This new Association Type is called "Policy Association Type" (PAT).
] specifies the mechanism for the capability advertisement of the Association Types supported by a PCEP speaker by defining an ASSOC-Type-List TLV to be carried within an OPEN object. This capability exchange for the PAT MUST
be done before using the Policy Association. Thus, the PCEP speaker MUST
include the PAT in the ASSOC-Type-List TLV and MUST
receive the same from the PCEP peer before using the PAG in PCEP messages.
The Policy Association Type (3) is operator configured (as specified in [RFC 8697
]), i.e., the association is created by the operator manually on the PCEP peers, and an LSP belonging to this association is conveyed via PCEP messages to the PCEP peer. There is no need to convey an explicit Operator-configured Association Range, which could only serve to artificially limit the available Association IDs. Thus, for the Policy Association Type, the Operator-configured Association Range MUST NOT
be set and MUST
be ignored if received.
A PAG can have one or more LSPs. The association parameters including Association Identifier, Policy Association Type (PAT), as well as the Association Source IP address are manually configured by the operator and are used to identify the PAG as described in [RFC 8697
]. The Global Association Source and Extended Association ID MAY
also be included.
As per the processing rules specified in Section 6.4
of RFC 8697
, if a PCEP speaker does not support this Policy Association Type, it would return a PCEP error (PCErr) message with Error-Type 26 "Association Error" and Error-value 1 "Association type is not supported". The PAG and the policy MUST
be configured on the PCEP peers as per the operator-configured association procedures. All further processing is as per Section 6.4
of RFC 8697
. If a PCE speaker receives a PAG in a PCEP message and the Policy Association information is not configured, it MUST
return a PCErr message with Error-Type 26 "Association Error" and Error-value 4 "Association unknown".
Associating a particular LSP with multiple policy groups is allowed from a protocol perspective; however, there is no assurance that the PCEP speaker will be able to apply multiple policies. If a PCEP speaker does not support handling of multiple policies for an LSP, it MUST NOT
add the LSP into the association group and MUST
return a PCErr with Error-Type 26 "Association Error" and Error-value 7 "Cannot join the association group".