Protection Methods for BIER-TE
Futurewei Technologies Inc.
Bouygues Telecom
University of Tuebingen
University of Tuebingen
This document proposes protection methods for the BIER-TE architecture [I-D.eckert-bier-te-arch]. These include 1+1 (live- live) path/tree [RFC7431] redundancy, 1:1 path/tree protection, as well as fast reroute (FRR) methods. The latter may protect against link and/or node failures and leverage infrastructure tunnels, BIER- in-BIER encapsulation, or header modification for implementation. In particular, this memo describes FRR for BIER-TE in detail. FRR for BIER-TE requires support from the BIER-TE controller and the BFRs that are attached to a link/adjacency for which FRR protection is desired. FRR relies on the BIER header described in [I-D.ietf-bier-architecture] which is also used by BIER-TE. It does not require extensions or modifications to existing BIER-TE tables. However, the presented FRR procedures need some additional forwarding plane logic on the BFR. An additional table is needed that carries information about pre-computed backup paths. When a failure is detected, the information from this table is used to modify the bitstring in the BIER header before forwarding a packet over a backup path. To prevent undesired packet duplication, packets should be tunneled on the backup paths.