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New Member

BGP over GRE tunnel

I want to set up an EGP peering with a remote router over a GRE tunnel via the internet (internet firewalls at each site provide encryption).

Currently I connect to the remote router

via my Telco's MPLS network and want to use the Tunnel to provide some redundancy. The tunnel is currently only being used to do some policy routing.

Are there any issues or is there any special bgp configuration required?


Re: BGP over GRE tunnel


assuming the tunnel is terminated on both BGP peersthere should be no problem. The routers will "see" the GRE tunnel as an interface and eBGP setup is normal because the neighbor is directly connected.

The only "problem" to be expected is MTU size being below 1500. But this is not an issue for BGP but for some applications. Enable path MTU discovery on the routers and "adjust-mss" to a suitable value. For BGP the IP unicast packets transporting the updates and hellos will be sent down the tunnel like any other traffic.

Regards, Martin

New Member

Re: BGP over GRE tunnel

I think there should be no problem in establishing the EBGP with the peer.But only advertise those routes which are necessary.MTU size is also important and certain applications work on different MTU sizes.