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New Member

Establish BGP adj across a router in bridge mode


I have a DS3 terminated on a 3825 with bridging configured with all interfaces in the same bridge group.The DS3 is frame-relay leading to my BGP neighbor.

I'm unable to get BGP established across the bridge. Frame is up and I can ping from BGP router 1 to the carrier neighbor.


The reason we want to do this is so we can have a failover router running BGP on this same single MPLS line.

I suspect it has to do with unicast forwarding but since BGP uses Unicast but I can't find where to enable this. I've tried ebgp-multihop but that gets no joy.


Carl King

Everyone's tags (3)
New Member

Re: Establish BGP adj across a router in bridge mode

Can you share your interfaces and BGP config? Hard to say without that.

Sent from Cisco Technical Support iPad App

New Member

Re: Establish BGP adj across a router in bridge mode

The basics are in the drawing, but here you go.

## Router MPLS-DS3

int g0/0

no ip address

bridge-group 1

int g0/1

no ip address

bridge-group 1

interface Serial0.100 point-to-point

no ip address

frame-relay interface-dlci 100 ietf

bridge-group 1


bridge 1 protocol ieee

bridge irb

## Router BGP router 1

ip routing

int g0/0

ip address

router bgp 64600

neighbor remote-as 65000

neighbor default-originate

Again, is pingable from, frame pvc is up.



New Member

Re: Establish BGP adj across a router in bridge mode

Carl, my apologies the iPad app does not show images that's why I couldn't see you diagram.

I would check few things. See what IP address BGP is using to connect with the command "show tcp brief" and look for any port 179 source IP. Make sure these match on your bgp neighbors.

Because of the frame relay you might need eBGP multihop, might want to check that.

One other thing I would try is use this command on the FR " frame-relay map bridge 100".

If anything fails, "debug ip bgp events" or "debug ip packet (acl)" with the acl of tcp port 179.

Hope that helps.