From cae770d31d306e5053c1c69509c03d11903217fa Mon Sep 17 00:00:00 2001 From: Christoffer Date: Thu, 23 Aug 2018 01:46:37 +0200 Subject: [PATCH] doc: Add documentation for IANA well-known communities Coded as part of #2684 and most code written while participating at BornHack@2018. bgp.rst: Explain what the communities does and a summarized edition of the communities purpose. Signed-off-by: Christoffer --- doc/user/bgp.rst | 74 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 74 insertions(+) diff --git a/doc/user/bgp.rst b/doc/user/bgp.rst index f1209c2172..2cea24a8bd 100644 --- a/doc/user/bgp.rst +++ b/doc/user/bgp.rst @@ -1011,6 +1011,75 @@ is 4 octet long. The following format is used to define the community value. ``internet`` ``internet`` represents well-known communities value 0. +``graceful-shutdown`` + ``graceful-shutdown`` represents well-known communities value + ``GRACEFUL_SHUTDOWN`` ``0xFFFF0000`` ``65535:0``. :rfc:`8326` implements + the purpose Graceful BGP Session Shutdown to reduce the amount of + lost traffic when taking BGP sessions down for maintainance. The use + of the community needs to be supported from your peers side to + actually have any effect. + +``accept-own`` + ``accept-own`` represents well-known communities value ``ACCEPT_OWN`` + ``0xFFFF0001`` ``65535:1``. :rfc:`7611` implements a way to signal + to a router to accept routes with a local nexthop address. This + can be the case when doing policing and having traffic having a + nexthop located in another VRF but still local interface to the + router. It is recommended to read the RFC for full details. + +``route-filter-translated-v4`` + ``route-filter-translated-v4`` represents well-known communities value + ``ROUTE_FILTER_TRANSLATED_v4`` ``0xFFFF0002`` ``65535:2``. + +``route-filter-v4`` + ``route-filter-v4`` represents well-known communities value + ``ROUTE_FILTER_v4`` ``0xFFFF0003`` ``65535:3``. + +``route-filter-translated-v6`` + ``route-filter-translated-v6`` represents well-known communities value + ``ROUTE_FILTER_TRANSLATED_v6`` ``0xFFFF0004`` ``65535:4``. + +``route-filter-v6`` + ``route-filter-v6`` represents well-known communities value + ``ROUTE_FILTER_v6`` ``0xFFFF0005`` ``65535:5``. + +``llgr-stale`` + ``llgr-stale`` represents well-known communities value ``LLGR_STALE`` + ``0xFFFF0006`` ``65535:6``. + Assigned and intented only for use with routers supporting the + Long-lived Graceful Restart Capability as described in + :rfc:`draft-uttaro-idr-bgp-persistence`. + Routers recieving routes with this community may (depending on + implementation) choose allow to reject or modify routes on the + presence or absence of this community. + +``no-llgr`` + ``no-llgr`` represents well-known communities value ``NO_LLGR`` + ``0xFFFF0007`` ``65535:7``. + Assigned and intented only for use with routers supporting the + Long-lived Graceful Restart Capability as described in + :rfc:`draft-uttaro-idr-bgp-persistence`. + Routers recieving routes with this community may (depending on + implementation) choose allow to reject or modify routes on the + presence or absence of this community. + +``accept-own-nexthop`` + ``accept-own-nexthop`` represents well-known communities value + ``accept-own-nexthop`` ``0xFFFF0008`` ``65535:8``. + :rfc:`draft-agrewal-idr-accept-own-nexthop` describes + how to tag and label VPN routes to be able to send traffic between VRFs + via an internal layer 2 domain on the same PE device. Refer to + :rfc:`draft-agrewal-idr-accept-own-nexthop` for full details. + +``blackhole`` + ``blackhole`` represents well-known communities value ``BLACKHOLE`` + ``0xFFFF029A`` ``65535:666``. :rfc:`7999` documents sending prefixes to + EBGP peers and upstream for the purpose of blackholing traffic. + Prefixes tagged with the this community should normally not be + re-advertised from neighbors of the originating network. It is + recommended upon receiving prefixes tagged with this community to + add ``NO_EXPORT`` and ``NO_ADVERTISE``. + ``no-export`` ``no-export`` represents well-known communities value ``NO_EXPORT`` ``0xFFFFFF01``. All routes carry this value must not be advertised to @@ -1030,6 +1099,11 @@ is 4 octet long. The following format is used to define the community value. it is considered as external BGP peer, so the route will not be announced to the peer. +``no-peer`` + ``no-peer`` represents well-known communities value ``NOPEER`` + ``0xFFFFFF04`` ``65535:65284``. :rfc:`3765` is used to communicate to + another network how the originating network want the prefix propagated. + When the communities attribute is received duplicate community values in the attribute are ignored and value is sorted in numerical order. -- 2.39.5