Support for Long-lived BGP Graceful Restart
Bruno Decraene, Jim Uttaro, Enke Chen, John Scudder · 2019
In this document we introduce a new BGP capability termed Long-lived Graceful Restart Capability so that stale routes can be retained for a longer time upon session failure. A well-known BGP community LLGR_STALE is introduced for marking stale routes retained for a longer time. A second well-known BGP community, NO_LLGR, is introduced to mark routes for which these procedures should not be applied. We also specify that such long-lived stale routes be treated as the least-preferred, and their advertisements be limited to BGP speakers that have advertised the new capability. Use of this extension is not advisable in all cases, and we provide guidelines to help determine if it is. We update RFC 6368 by specifying that the LLGR_STALE community must be propagated into, or out of, the path attributes exchanged between PE and CE.