8.1.1. Constructing the Ethernet Segment Route

8.1.1. Constructing the Ethernet Segment Route

The Route Distinguisher (RD) MUST be a Type 1 RD [RFC4364]. The value field comprises an IP address of the PE (typically, the loopback address) followed by a number unique to the PE.

The Ethernet Segment Identifier (ESI) MUST be set to the 10-octet value described in Section 5.

The BGP advertisement that advertises the Ethernet Segment route MUST also carry an ES-Import Route Target, as defined in Section 7.6.

The Ethernet Segment route filtering MUST be done such that the Ethernet Segment route is imported only by the PEs that are multihomed to the same Ethernet segment. To that end, each PE that is connected to a particular Ethernet segment constructs an import filtering rule to import a route that carries the ES-Import Route Target, constructed from the ESI.