BGP default route

[kamtarias]

1. Heathrow is a Data Center and is originating Default route to other HQ's named - Slough, Swindon, Germany, and Bracknell.
2. All HQ's are learning Default route from Heathrow DC.
3. All HQ and DC's are having CE's and connected to BT MPLS cloud. BGP is running between CE- PE.
4. No idea about MPLS Cloud, but expecting Generic config that will have MPBGP running and having VRF for Customer.
5. My Goal is to make Swindon as DC and advertise a default route from Swindon but that default route should be only applicable for Bracknell HQ and not others.
6. Can somebody help to achieve this? Diagram has also been attached to Query

[Georg Pauwen]

Hello,

my first thought is to simply establish a neighbor on Swindon with Bracknell, and use the 'neighbor x.x.x.x default-originate' command. 

[kamtarias]

Hi Georg,

Many Thanks for looking into it and providing the best solution. However, I apologize for not explaining the Question properly. Basically Currently Heathrow is acting as a Head Quarter and rest all are acting as Branches. Long-term Goal is to shut down Heathrow and make Swindon as Head Quarter. Solution works if there is a single Branch office, however, there are many Branches and I do not feel to advertise default route individually for every Branch office. Hope My query is making more sense now?? 

[Jon Marshall]

You can't do what Georg suggests because you do not peer between your sites, you peer with your provider PEs  (unless I have misunderstood what he was suggesting).

You can't really do this without the help of your provider because basically Bracknell simply sees the PE as the next hop for the default route, it is the PE routers that choose the best default route. 

You would need to advertise the default route from Heathrow with a specific community and the one from Swindon with a different community and then your provider would need to choose which default route to advertise to which site(s) based on the community, assuming your provider would do this. 

Alternatively you could create a GRE tunnel directly between Swindon and Bracknell and advertise a default through the tunnel and prefer it over the default via MPLS (or simply filter that default route out). 

Sorry but as you do not really control the routing within the MPLS network there is no easy way to do this, or at least none that I am aware of. 

Jon

[Georg Pauwen]

Jon is right, my 'solution' would only work in conjunction with a tunnel that would make direct peering possible.

How is Heathrow announcing the default route ?

[kamtarias]

router bgp 64521
no synchronization
bgp log-neighbor-changes
network 10.101.65.0 mask 255.255.255.0
redistribute connected
redistribute static
neighbor 172.23.24.25 remote-as 12345
neighbor 172.23.24.25 ebgp-multihop 5
neighbor 172.23.24.25 default-originate
no auto-summary
R8#

[kamtarias]

router bgp 64521
no synchronization
bgp log-neighbor-changes
network 10.101.65.0 mask 255.255.255.0
redistribute connected
redistribute static
neighbor 172.23.24.25 remote-as 12345
neighbor 172.23.24.25 ebgp-multihop 5
* neighbor 172.23.24.25 default-originate*
no auto-summary
R8#