that is, your ip core and edge are sort of very "close" to each other. it's not like, say, in uunet, where this architectural distance is greater. true? -- dima.

-----Original Message----- From: Chris Liljenstolpe [mailto:chris@cw.net] Sent: Wednesday, July 12, 2000 7:13 AM To: Dmitri Krioukov; Bora Akyol Cc: nanog Subject: RE: Running BGP4 on a Core Router

Dimirtri,

I have to disagree with you on this statement. While the physical trunks are not connecting routers together in the C&W network, there is most definately an IP core. The L2 core provides a mesh for core routers at each site, wich provide the hierarchy for edge/fannout routers. Therefore we have both an IP and L2 core with the IP core overlayed over the L2 core.

Chris

--On Tuesday, 11 July 2000 21.54 -0400 Dmitri Krioukov <dima@krioukov.net> wrote:

...

we can even imagine some core that is not ip core but, say, atm core and all lsrs are atm-lsrs.

actually some providers (like c&w) have exactly this no ip core, overlay model. it's far from being the best one. -- dima.

...

-----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu]On Behalf Of Bora Akyol Sent: Monday, July 10, 2000 12:10 AM To: nanog Subject: Re: Running BGP4 on a Core Router

Even with MPLS, you need to run some sort of a routing protocol.

ISIS or OSPF with TE extensions would do.

One can also use BGP with MPLS Label extensions as well. By

the way, how

...

...

does this work with route reflectors?

Bora

----- Original Message ----- From: "Jesper Skriver" <jesper@skriver.dk> To: "HANSEN CHAN" <hansen.chan@alcatel.com> Cc: <nanog@merit.edu> Sent: Sunday, July 09, 2000 8:20 PM Subject: Re: Running BGP4 on a Core Router

...

On Sun, Jul 09, 2000 at 07:49:37PM -0400, HANSEN CHAN wrote:

...

Hi folks,

I was hearing that typically BGP4 is run on all routers

inside a POP,

...

...

including access routers connecting to customers, border routers connecting other ISPs and core routers connecting to other POPs in the same network.

I can understand why BGP4 is run on access and border routers. But running BGP4 on core routers is beyond my understanding. I thought you don't need to run BGP4 on core routers which are considered to be interior nodes.

Can someone shed some light on what is the benefit of running BGP4 on the core routers?

If these routers run "normal" ip routing you have to, as each router does a lookup of the destination ip address of each packet, and forward it accordingly.

If you run MPLS, you don't have to, as it uses labels to get to the next-hop router.

/Jesper

-- Jesper Skriver, jesper(at)skriver(dot)dk - CCIE #5456 Work: Network manager @ AS3292 (Tele Danmark DataNetworks) Private: Geek @ AS2109 (A much smaller network ;-)

One Unix to rule them all, One Resolver to find them, One IP to bring them all and in the zone to bind them.