[c-nsp] BGP Architecture Question

[Rodney Dunn]

Actually, I just helped a customer implement
an exact setup like this a couple days ago.

They did the egress load balancing with OER
and it's working nicely for them.

I'm in the process of typing up a tech doc
on it.

But basically we pointed the default route
at the HSRP address.  We only received a
default from the providers.

We then made one of the Routers the
OER master while both of the routers served
as OER borders.

We did the egress load balancing based on 
link utilization such that the links would always
bee within 10% of each other.

On Wed, Nov 17, 2004 at 01:18:09PM +0100, Olav Langeland wrote:
> > -----Original Message-----
> > From: Christopher Martinsen [mailto:cmartinsen at viatraining.com] 
> > Sent: 17. november 2004 00:47
> > To: cisco-nsp
> > Subject: [c-nsp] BGP Architecture Question
> > 
> > I am going to be setting up BGP for my company.
> > 
> > I have secured two T1 circuits, each from different ISP's.
> > I have secured an AS number for my organization.
> > I have secured a full class C address space.
> > 
> > The question that I have is about architecture.
> > 
> > I will have each T1 going into a seperate router. I have
> > one Cisco 2621 and one Cisco 2621XM.
> > 
> > I believe that with BGP the incoming traffic will be somewhat
> > load balanced as well as connectivity for my organization will
> > be redundant should one of the circuit go down.
> > 
> > I want to know the best way to architect the LAN side of the 
> > connection. I will have:
> > 
> > 	T1		T1
> > 	\		/
> > 	 \	       /
> > 	 Router	     Router
> > 	    \	     /
> > 	      Switch 	
> > 		|
> > 	    PIX Firewall
> > 	    
> > If I put a switch between the firewall and routers. How can I set the 
> > outbound traffic to be load balanced?
> > 
> > I'm not sure what options are available to me. I'm hoping 
> > that someone can provide me with some options and insights 
> > on the best way to architect this.
> > 
> > Thanks,
> > 
> > Chris
> 
> Here are some links from cisco.com about BGP, second one is a
> configuration example for multihoming (which is what you want):
> http://www.cisco.com/pcgi-bin/Support/PSP/psp_view.pl?p=Internetworking:
> BGP
> http://www.cisco.com/warp/public/459/27.html
> 
> Internal setup can be done with HSRP on the LAN interfaces on your
> routers, and iBGP between your routers. This will mean that some traffic
> goes twice in your network since it can go Firewall -> HSRP IP to
> Router1 -> iBGP decides it should go out via second router -> Router2 ->
> Internet. But it will give you redundancy, if Router1 goes down the HSRP
> is taken over by Router2 and traffic will continue to flow. 
> 
> If this is acceptable depends on your network and how much traffic you
> have, but it's a decent design solution. For doing more with load
> sharing on outbound traffic there are several ways of achieving this
> including localpref
> (http://www.cisco.com/en/US/tech/tk365/tk80/technologies_configuration_e
> xample09186a00800945bf.shtml#conf5). 
> 
> 
> Regards,
> Olav Langeland
> 
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