Re: BGP advertise-best-external on RR

[Mohamed Kamal <mkamal () noor net>]

Hi,

Diverse-path will only send the second best path, and in my case I have 
three routes not two. In addition to that, every PE will have to peer 
with the RR via a second session (on the same RR, as I will not deploy a 
new standalone shadow RR) and this will increase the BGP sessions to the 
double.

Add-path will have a network-wide IOS upgrade for this BGP capability to 
be supported which is not viable now.

So, is there any other recommendation other than the internet VRF with 
different RDs solution?

Regards,

Mohamed Kamal
Core Network Sr. Engineer

On 8/25/2015 11:37 AM, Jeff Tantsura wrote:
> Hi,
>
> In your case I¹d recommend to use diverse path, due to its simplicity and
> non disruptive deployment characteristics.
> As you know - diverse path requires additional BGP session per additional
> (second, next, etc) path, in most cases not a problem, however mileage
> might vary.
>
> To my memory, in Cisco land - it has only been implemented in IOS, not XR,
> please check.
>
> Cheers,
> Jeff
>
>
>
>
> -----Original Message-----
> From: Diptanshu Singh <diptanshu.singh () gmail com>
> Date: Monday, August 24, 2015 at 10:53 PM
> To: Mohamed Kamal <mkamal () noor net>
> Cc: "nanog () nanog org" <nanog () nanog org>
> Subject: Re: BGP advertise-best-external on RR
>
> > Yes . In the case of diverse path , shadow route reflector will be the
> > one wherever  you enable commands to trigger diverse path computation.
> >
> > Good thing with diverse path is that the RR-Clients don't have to have
> > any support but bad thing is that it can only reflect One additional
> > best-path( second best path ) .
> >
> > Sent from my iPhone
> >
> > > On Aug 24, 2015, at 2:31 PM, Mohamed Kamal <mkamal () noor net> wrote:
> > >
> > > It's only supported on the 15.2(4)S and later not the SRE train. I
> > > might consider an upgrade.
> > >
> > > One more question regarding this, can you configure the RR to be the
> > > main and shadow RR?
> > >
> > > Mohamed Kamal
> > > Core Network Sr. Engineer
> > >
> > > > On 8/24/2015 9:16 PM, Diptanshu Singh wrote:
> > > > BGP Add-Path might be your friend . You can look at diverse-path as
> > > > well .