IS-IS SPRING Anycast SID

This feature introduces support for IS-IS segment routing anycast prefix segments, in addition to node segments, for prefixes that are advertised by the IS-IS protocol through policy configuration. An IS-IS SR anycast segment is an IS-IS prefix segment that identifies a set of routers. An anycast segment enforces forwarding based on the equal-cost multipath-aware shortest path toward the closest node of the anycast set. Within an anycast group, all the routers advertise the same prefix with the same SID value, which facilitates load balancing.