A Framework for Fast Reroute with Bit Index Explicit Replication (BIER-FRR)

This document provides a framework for the development of Fast Reroute (FRR) mechanisms for Bit Index Explicit Replication forwarding (BIER-FRR). BIER-FRR can provide protection against link or BFR failure by invoking locally pre-determined repair paths that can react in the same time-scales as (unicast) FRR for MPLS or IP networks - "sub 50msec", and without the creation of additional per- path or per-flow state coordinated across multiple routers/LSR. BIER-FRR can be implemed locally within a router/LSR with minimal interoperability requirements against other router/LSR. It can therefore easily be introduced incrementally or selectively where needed. BIER-FRR implementing nodes only need to understand the routing topology of the network for calculation of repair paths and know what type of unicast encapsulation can be used to send ("tunnel") BIER packets to remote BFR. This document proposes and discusses different options for BIER forwardng (BIFT) extensions to support BIER-FRR. These are exemplary and non-normative. This document does not specify any standards or experiments but aims to support such efforts.