The user enables the signaling of the primary LSP path admin-group constraints in the FRR object at the ingress LER with the following CLI command:
config>router>mpls>lsp>fast-reroute>propagate-admin-group
When this command is enabled at the ingress LER, the admin-group constraints configured in the context of the P2P LSP primary path, or the constraints configured in the context of the LSP and inherited by the primary path, are copied into the FAST_REROUTE object. The admin-group constraints are copied into the ‟include-any” or ‟exclude-any” fields.
During LSP signaling to the downstream node, the ingress LER also propagates the admin-group constraints, which allows the node to include these constraints in the selection of the FRR backup LSP for LSP primary path protection.
The ingress LER inserts the FAST_REROUTE object, by default, in a primary LSP path message. If the user disables the object using the config>router>mpls>no frr-object command, the admin-group constraints are not propagated.
The same admin-group constraints can be copied into the Session Attribute object for use by LSR, typically an ABR, to expand the ERO of an inter-area LSP path. The constraints are also used by any LSR node in the path of a CSPF or non-CSPF LSP to check the admin-group constraints against the ERO, regardless of whether the hop is strict or loose. These constraints are governed strictly by the config>router>mpls>lsp>propagate-admin-group command.
That is, the user can copy the primary path admin-group constraints into only the FAST_REROUTE object, or only the Session Attribute object, or both.
The point-of-local repair (PLR) rules for admin-group constraint processing can use either FAST_REROUTE or Session Attribute object admin-group constraints.