BGP Route Reflection

[CSCO11254628]

Hello,

Please i want to confirm if I need a direct connection between my RR and the clients or I just need to have a TCP connection set up between them?

[Lei Tian · Accepted solution]

Hi,

No need for direct connection between RR and client. Same as other iBGP neighbrs.

HTH,

Lei Tian

[John Blakley · Accepted solution]

As long as you have a route to the peer, either static or another routing protocol, you can peer up. As Lei stated, you don't need to be directly connected like other routing protocols (where they need a shared subnet to form an adjacency).

HTH,
John

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[milan.kulik · Accepted solution]

Hi,

as the other guys said here, direct connection is not necesary to establish a BGP connection between RR and his client.

But still you need to be sure all routers within your AS (including those on the path between the RR and his client) do know the routing info necessary to forward packets to the destinations advertised by BGP prefixes.

So you either need some BGP redistibution to your IGP (OSPF, e.g.) - in that case you don't need RR though - or each router inside your AS to be a client of some RR.

Which brings a conclusin the easiest practice is to make your router a client of some directly connected RR :-)

Bets regards,

Milan

[Harold Ritter]

Hi Milan,

That is an excellent point that, generally, transit routers in the AS would need to run BGP and know all the routes advertised via BGP. In service provider cores though, it is common that only the edge routers run BGP (to the RRs). Core routers are what we call BGP free. The connectivity between the ingress and egress routers, in such a scenario, is provided by MPLS, hence the core routers not needing to know all the BGP routes, only the IGP routes.

Regards