bgp conditional peering

Unanswered Question
Aug 11th, 2007

hi everyone, i had a question regarding bgp.

Suppose i have 2 routers peering with an ISP ( whether same ISP or 2 different ISP ) lets name these routers RA and RB. i want RB to make a peering session with its ISP if and only if RA fails its bgp session, now u can also assume that RA fails completely or just loses its bgp connection, in either case i want RB to start its own bgp session, so i want to make RB backup of RA in terms of BGP.

how can it be possible

I have this problem too.
0 votes
  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 0 (0 ratings)
criss_noh Sun, 08/12/2007 - 21:10

yes. that is commonly used. you can have backup line via BGP or have 2 paths likely loadbalancing.

illusion_rox Mon, 08/13/2007 - 00:47

can u kindly tell me that how its possible ? what configuration i have to do ???

royalblues Mon, 08/13/2007 - 01:09

The only way i could think of achieving this is by configuring BGP over loopbacks and making sure that it is reachable only when your primary links come up.


criss_noh Thu, 09/20/2007 - 20:48

that is very simple. you just command maximum-path 2. but please make sure all of BGP best path selection procedure.

router bgp 10

neighbor x.x.x.x remote-as xxxx

maximum-paths 2


etienne.basset Thu, 09/20/2007 - 23:55


i don't know exactly why you want to to this but you should do like this :





then RA set localpref150 on incoming routes,

RB do as path prepend on outgoing routes...

it's more clean than 'conditionnal peering'


criss_noh Sat, 09/22/2007 - 19:23

Dear etienne,

I guess that he wants to have 2 paths on the same router. this means link redundency vis bgp not router redundency.


This Discussion