An Optional Encoding of the BIFT-id Field in the non-MPLS BIER Encapsulation

Bit Index Explicit Replication (BIER) is an architecture that provides optimal multicast forwarding through a "multicast domain", without requiring intermediate routers to maintain any per-flow state or to engage in an explicit tree-building protocol. The Multicast packet is encapsulated using a BIER Header and transported through an MPLS or non-MPLS network. When MPLS is used as the transport, the Bit Indexed Forwarding Table (BIFT) is identified by a MPLS Label. When non-MPLS transport is used, the BIFT is identified by a 20bit value. This document describes one way of encoding the 20bit value.