BGP advertise-best-external on RR

Diptanshu Singh diptanshu.singh at gmail.com
Mon Aug 24 19:16:41 UTC 2015


BGP Add-Path might be your friend . You can look at diverse-path as well .

Sent from my iPhone

> On Aug 24, 2015, at 2:07 PM, Mohamed Kamal <mkamal at noor.net> wrote:
> 
> Hi,
> 
> I have a classic network design with 3 gateways, each receive a default route from different upstream provider. Each gateway has a BGP session with a route-reflector, which in turns reflects the best BGP route to the other PE routers in the network. The route-reflectors are running the SRE train (12.2(33)SRE1) and here exist the problem.
> 
> I need to leak all the default routes (3 default routes) from the gateways into the PE routers. I have done this via bgp advertise-best-external on the gateways. So far, the default routes exist on the route-reflector, however it's suppressed as the RR will only send the best path.
> 
> I have configured bgp advertise-best-external also on the RR but it didn't work, because the RR didn't see that the different default routes received are of "external" type. Cisco didn't state that clearly and it only stated that bgp best external feature won't work on the RR unless you get an ASR loaded with an IOS-XE 3.4 or later!
> 
> Anyhow, do anyone here has a suggestion of how to get this done without replacing my RR sticking to this classical network design?
> 
> Thanks.
> 
> -- 
> Mohamed Kamal
> Core Network Sr. Engineer
> 



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