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Default Route BGP Query

Hello all.

I'm hoping someone will offer a hand. I'm trying to achieve failover in a slightly strange scenario without using a full routing table.

I use a Catalyst 3550 and because it's limited I just take a default route off an ISP via two BGP neighbours. I use "ip route 0.0.0.0

0.0.0.0 172.1.1.1" to push all outgoing traffic to them using their private LAN IP.

I want to add another bandwidth provider but all I will be given is another private IP 172.1.1.2 to send traffic to. I can easily write a script to ping the primary IP periodically and change the default route if it fails to respond for outgoing traffic.

My question is how do I affect incoming traffic if the primary provider has problems but is still visible to my pings ?

The two bandwidth providers will be visible from the same BGP neighbours so I can't drop the sessions and stop advertising them or pad out with prepends. I also only connect to one physical port.

Any help greatly appreciated ! I'm stumped.

JR

Reply to
Jonathan Ross
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I'm confused. You said you're using BGP to get the default route, but then you show a static default route. Are you talking about two different routers?

It would probably be better to use a routing protocol.

I don't understand this, either.

Could you draw a diagram?

Reply to
Barry Margolin

Hi Barry,

Thanks for having a look. I hope I can explain clearly.

The upstream router that the Catalyst will talk to is from Arbinet (a trading exchange) who offer multiple 'seller' connections to get IP Transit from when you're a 'buyer'. When they send you a default route instead of a full routing table it's possible to script around their private LAN IPs to affect which seller outgoing traffic is pushed out through (using that static default route shown) but I can't think of a way of affecting the incoming traffic.

Any help greatly appreciated.

JR

Barry Margol> >

Reply to
Jonathan Ross

Sorry I should have said that yes it is two routers, one from each seller and Arbinet 'mask' their connection with me but just inject whatever providers I have asked to buy from from their two neighbors.

They have said that more than one incoming default route means that incoming traffic will be round robin between the bandwidth providers because there's no best path choice.

Thanks,

JR

J> Hi Barry,

Reply to
Jonathan Ross

Thanks. But why did you have to top-post?

When you have multiple providers and want to be able to make inbound traffic fail over between them, you need to advertise routes using BGP, not just get a default route that way. Then, when one of the provider connections fails, the BGP session will go down and that advertisement will go away.

Reply to
Barry Margolin

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