BGP Route Propagation Without Population

[gameretail]

Morning/Afternoon all,

I'm in the process of designing a new data centre infrastructure and the technical architect that I'm working with has come up with a wacky idea that involves having an eBGP relationship established with our Internet providers on a router that then passes off the routes to one of it's iBGP peers without letting the routes populate in its routing table. This is largely because the eBGP peering router can't handle the entire Internet routing table as much as the internal router can. This sounds like some kind of jujumagic to me but I wanted to check whether it's possible or not with people that undoubtedly have a great deal more experience than me.

I realize that the easiest thing to do in this scenario would be to have the router that can handle the internet routing table as the eBGP edge gateway to our service providers but I believe that the architect has some exciting ideas that involve DDoS mitigation that mean that we want to do things in the way specified above.

Thanks in advance,

Tom

[eduardopozo56]

You can prevent BGP from installing routes into RIB by using "BGP Selective Route Download" feature. This feature is commonly used on Route Reflector deployments, where you dont really need to install the routes on the RIB, only receive them on BGP and pass them to your peers.

More Info:

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/15-s/irg-15-s-book/irg-selective-download.html

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_bgp/configuration/xe-3s/irg-xe-3s-book/irg-selective-download.pdf