The configuration of the resolution of a static route prefix to set of MPLS LSPs is described in Static route resolution using tunnels which also provides the selection rules among multiple LSP types: RSVP-TE, SR-TE, LDP, SR-ISIS, and SR-OSPF. A static route of a prefix can only be resolved to a set of tunnel next-hops of the same type though, for each indirect next-hop.
To perform ECMP over a set of configured MPLS LSPs, the user must enter two or more LSP names to be used as tunnel next-hops. If automatic selection is performed, ECMP is performed if two or more MPLS LSPs are in TTM to the indirect next-hop of the static route. However, all LSPs must have the same LSP metric; otherwise, only the tunnel next-hops with the same lowest metric are activated for the static route.
The user can force the metric of an LSP to a constant value using the following command:
- config>router>mpls>lsp>metricIf the user enters, for the same static route, more LSP names with the same LSP metric than the value of the router level ecmp option, only the first configured LSPs equal to the ecmp value are selected. The remaining tunnel next-hops for the route are not activated. When automatic MPLS LSP selection is performed in TTM, the lowest tunnel ID is used as a tie-breaker among the same lowest metric LSPs.
To perform weighted load-balancing over the set of MPLS LSPs, either when the LSP names are provided or when auto-selection in TTM is performed, the user must also enable the weighted ECMP globally like for static, IGP, and BGP prefixes resolving to IGP shortcuts:
- config>router>weighted-ecmp