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| author | Rubens Figueiredo <rubens.figueiredo@bisdn.de> | 2019-03-20 14:24:25 +0100 |
|---|---|---|
| committer | Rubens Figueiredo <rubens.figueiredo@bisdn.de> | 2019-03-21 10:34:28 +0100 |
| commit | 749afd7dcef9f3fcc3f30b27722fb26c990529e1 (patch) | |
| tree | 92cebd830f560171383e48897369cf8a4e5a1e0e /doc | |
| parent | Merge pull request #3977 from opensourcerouting/bfd-small-fixes (diff) | |
| download | frr-749afd7dcef9f3fcc3f30b27722fb26c990529e1.tar.xz frr-749afd7dcef9f3fcc3f30b27722fb26c990529e1.zip | |
doc: route reflector documentation
Signed-off-by: Rubens Figueiredo <rubens@bisdn.de>
Diffstat (limited to 'doc')
| -rw-r--r-- | doc/user/bgp.rst | 22 |
1 files changed, 17 insertions, 5 deletions
diff --git a/doc/user/bgp.rst b/doc/user/bgp.rst index 5b453e75c..3aee1940b 100644 --- a/doc/user/bgp.rst +++ b/doc/user/bgp.rst @@ -511,8 +511,8 @@ cause may lead to routing instability or oscillation across multiple speakers in iBGP topologies. This can occur with full-mesh iBGP, but is particularly problematic in non-full-mesh iBGP topologies that further reduce the routing information known to each speaker. This has primarily been documented with iBGP -route-reflection topologies. However, any route-hiding technologies potentially -could also exacerbate oscillation with MED. +:ref:`route-reflection <bgp-route-reflector>` topologies. However, any +route-hiding technologies potentially could also exacerbate oscillation with MED. This second issue occurs where speakers each have only a subset of routes, and there are cycles in the preferences between different combinations of routes - @@ -2240,10 +2240,15 @@ Displaying Routes by AS Path Route Reflector =============== -.. note:: This documentation is woefully incomplete. +BGP routers connected inside the same AS through BGP belong to an internal +BGP session, or IBGP. In order to prevent routing table loops, IBGP does not +advertise IBGP-learned routes to other routers in the same session. As such, +IBGP requires a full mesh of all peers. For large networks, this quickly becomes +unscalable. Introducing route reflectors removes the need for the full-mesh. -.. index:: bgp cluster-id A.B.C.D -.. clicmd:: bgp cluster-id A.B.C.D +When route reflectors are configured, these will reflect the routes announced +by the peers configured as clients. A route reflector client is configured +with: .. index:: neighbor PEER route-reflector-client .. clicmd:: neighbor PEER route-reflector-client @@ -2251,6 +2256,13 @@ Route Reflector .. index:: no neighbor PEER route-reflector-client .. clicmd:: no neighbor PEER route-reflector-client +To avoid single points of failure, multiple route reflectors can be configured. + +A cluster is a collection of route reflectors and their clients, and is used +by route reflectors to avoid looping. + +.. index:: bgp cluster-id A.B.C.D +.. clicmd:: bgp cluster-id A.B.C.D .. _routing-policy: |