The 7705 SAR allows an explicit SID value to be configured for each hop in an SR-TE LSP path. The SID value for an SR-TE LSP hop is configured using the sid-label parameter under the config>router>mpls>path>hop context.
The sid-value parameter specifies an MPLS label value for that hop in the path.
The 7705 SAR supports a path computation method per LSP while allowing a mix-and-match configuration for primary and secondary paths. For example, primary and secondary paths can be different types: IP-to-hop paths or SID-based paths.
When SIDs are explicitly configured for a path, the user must provide all of the necessary SIDs to reach the destination. The router does not validate whether the whole label stack provided is correct other than checking that the top SID is programmed locally. A path can come up even if it contains SIDs that are invalid. The user or controller programming the path should ensure that the SIDs are correct.
A path must consist of either all SIDs or all IP address hops.
Paths containing explicit SID values can only be used by SR-TE LSPs.