RES: [c-nsp] Different Traffic thru BGP links

Tue Nov 23 14:07:33 EST 2004

Well..I'm gonna try to explain better. Tell me if I'm not clear again ;)

I have two internet peerings with providers A and B that I'm exporting their routes for all my customers (plus all the other internet routes). 

Today one of my customers has one Link with me (let's call link01) that I'm exporting all the internet routes to him and I'm receiving his prefixes and announcing them to all my peerings (too many than providers A and B) and other customers. 

This customer wants a new link (let's call link02) and he wants the traffic in the link02 will be only traffic between his AS and the AS from providers A and B. Remember, that I will keep exporting routes from this two providers to other customers. The link01 will have all other internet traffic with providers different from A and B.

In customer side is quite simple to solve this using local-preference to select which routes will prefer such link (also in link02 I'm announcing only routes from A and B to my customer). But in the reverse side, I mean, from my backbone to customer way, how do I do this? The prefixes that the customer announced to me are the same in link01 and link02 and I cannot use local-preference since the rule will be for all the traffic, not only from the origineted from providers A and B. 

So that's my question..is there a way to solve this without using Policy Based Routing(PBR) doing the forward of the packets by the source IP address which is not desirable cause both links are 100Mbps and it will consume a lot of resources from the equipment.

Any ideas?

Thanks in advanced!

Anderson

-----Mensagem original-----
De: Zaheer Aziz [mailto:zaziz at cisco.com]
Enviada em: terça-feira, 23 de novembro de 2004 14:29
Para: Brian Turnbow
Cc: Zaheer Aziz; BRA-SAO-Tomaiz,Anderson Goncalves;
cisco-nsp at puck.nether.net
Assunto: RE: [c-nsp] Different Traffic thru BGP links

At 04:43 PM 11/23/2004 +0100, Brian Turnbow wrote:
>
>If your using 2 routers twords the customer you can set up traffic shaping 
>tunnels to each router using MPLS, one for the direct peer traffic, one 
>for internet and
>use local weight to route twords the customer, that way you could still 
>have redundancy

if you use VRFs to separate link A,B, and C then it is difficult to fall 
back to global routing table that is where the redundancy issue comes up.
Perhaps Anderson should explain his topology a bit more(diagram) so we 
would all be on the same page. Currently we are not.

Thanks
Zaheer

>-----Original Message-----
>From: cisco-nsp-bounces at puck.nether.net 
>[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Zaheer Aziz
>Sent: martedì 23 novembre 2004 16.08
>To: BRA-SAO-Tomaiz,Anderson Goncalves
>Cc: cisco-nsp at puck.nether.net
>Subject: Re: [c-nsp] Different Traffic thru BGP links
>Importance: High
>
>At 04:23 PM 11/22/2004 -0200, BRA-SAO-Tomaiz,Anderson Goncalves wrote:
> >Hi Guys,
>
>
>This is how I understood your problem,
>
>You have ISP connections on Link C and D.
>
>You have two providers on say link A and B that must use Link C of your ISP.
>
>Link D of your ISP must only be used by your customers and others for 
>general Internet traffic.
>
>PBR on A and B was your first thought but due to high amount on traffic on 
>Link A and B, it could be an issue.
>
>You could use MPLS_VPN and put A, B and C in a VRF but you must understand 
>that you will loose redundancy, for not using link D in case of failures 
>on C. You could solve this with lots of vrf aware statics as backups but 
>it may not scale.
>
>If my understanding of your topology is right then Local_pref that others 
>have suggested will not work because all traffic will follow Link C which 
>is what you dont desire.
>
>Thanks
>Zaheer
>
>
> >I have a situation where an ISP (running BGP) will have two links with
> >my AS backbone.
> >In one of them it must allow to pass only peering traffic (from two
> >other providers that I have direct connection) and thru the other one
> >normal internet traffic.
> >To route traffic inbound my AS is simple. Only using local-preference
> >in the BGP at the customer side, but the problem is how to route
> >traffic outbound my AS to the customer side, since the prefixes
> >announced are keeped at the same routing table and are the same on both 
> links.
> >Use PBR is not desirable, cause there are too many prefixes and to much
> >traffic thru these connections. I'm also running MPLS VPN in my
> >backbone, if it has some solution based on this.
> >
> >Does anyone has a solution or see it before?
> >
> >Thanks for help!
> >
> >Anderson
> >
> >
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