BGP Label Aggregation - Automatic by Site of Origin attribute

This feature introduces automatic label aggregation for labeled BGP prefixes (inet labeled-unicast, inet6 labeled-unicast, and inet-vpn labeled-unicast) sharing the same site-of-origin (SOO) community. When labeled BGP prefixes are originated with a unique label per-prefix, it leads to the creation of many next hops on the receiving provider edge (PE) device. This might lead to scaling challenges in an environment with a large number of prefixes. One way to address this scaling challenge is automatic label aggregation. The PE device originating labeled BGP prefixes attaches a different site-of-origin (SOO) community for each set of labeled prefixes that shares the same next hop. Thus, within each set, labeled prefixes have different labels (per-prefix label allocation) but the same SOO. A route reflector, when reflecting these labeled prefixes, selects a single label, picked from one of the prefixes within the set identified by SOO, and uses this single label for all reflected prefixes of the given set. Essentially, the route reflector converts the label scheme from per-prefix to per-next-hop. This reduces the next-hop scaling pressure on the PE device receiving labeled BGP prefixes.