About MPLS Label Imposition
An outgoing label stack having one or more labels can be statically provisioned using the MPLS Label Stack Imposition feature. The outgoing label stack is used in the following two types of statically configured MPLS bindings:
Prefix and Label to Label Stack - Here an IP prefix or an incoming label is mapped to an outgoing stack, similar to static MPLS. An incoming prefix is mapped to out-label-stack for IP-only ingress traffic.
Label to Label Stack - Here only an incoming label is mapped to an outgoing stack without any prefix.
The new MPLS binding types are implemented in the static MPLS component and are available only when the feature mpls segment-routing command is enabled.
If configured next-hops of MPLS label imposition are SR recursive next-hops (RNH), then they are resolved to actual next-hops using RIB. The outer label of the out-label stack is imposed automatically from the SR allocated labels.
ECMP is also supported by adding a number of path configurations.
The static MPLS process is started when either the feature mpls segment-routing command or the feature mpls static command is run. Certain standard static MPLS commands will not be available when static MPLS is run using the feature mpls segment-routing command, and the commands for MPLS bindings will not be available when the feature mpls static command is run.