BIER Fast Reroute
draft-merling-bier-frr-00
| Document | Type |
Expired Internet-Draft
(individual)
Expired & archived
|
|
|---|---|---|---|
| Authors | Daniel Merling , Michael Menth | ||
| Last updated | 2019-09-06 (Latest revision 2019-03-05) | ||
| RFC stream | (None) | ||
| Intended RFC status | (None) | ||
| Formats | |||
| Stream | Stream state | (No stream defined) | |
| Consensus boilerplate | Unknown | ||
| RFC Editor Note | (None) | ||
| IESG | IESG state | Expired | |
| Telechat date | (None) | ||
| Responsible AD | (None) | ||
| Send notices to | (None) |
This Internet-Draft is no longer active. A copy of the expired Internet-Draft is available in these formats:
Abstract
BIER is a scalable multicast overlay [RFC8279] that utilizes some routing underlay, e.g., IP, to build up its Bit Index Forwarding Tables (BIFTs). This document proposes a Fast Reroute Extension for BIER (BIER-FRR). In case of a link or node failure, the routing underlay may first utilize FRR techniques to restore connectivity and then its forwarding tables converge. After that, BIER can update its BIFTs, which requires time. BIER packets may not be delivered until the last procedure has finished. With BIER-FRR, a BIER Forwarding Router (BFR) can deliver BIER packets again after a link or node failures as soon as the connectivity within the routing underlay is restored and the BFR is informed about a next-hop (NH) that is unreachable on a lower layer. BIER-FRR provides a mode for link protection and node protection. For link protection, it tunnels traffic to the next-hop using the underlying routing. For node protection, it forwards BIER packets to their specific next-hop and next-next-hops using tunnels in the underlying routing after applying a suitable backup bitmask to the bitstring in the BIER header of each packet. This procedure prevents duplicates. If topology allows, BIER-FRR achieves full protection against any single component failure. For link protection, BIER-FRR requires only a minor change to the forwarding logic. For node protection, BIER-FRR also requires backup entries in the BIFT. This document describes the concept and operating principles of BIER- FRR. It defines the necessary modifications to the BIER forwarding Procedure and the BIFT, and explains how backup entries are computed.
Authors
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