Nice Route Failover Question/Scenario

Unanswered Question
Jun 28th, 2008

Hi, Folks:

I have a scenario in which we connect to a vendor at 2 locations, our primary data center and secondary data center. Company 'A' initiates the traffic always.

My question involves failover scenarios and how the architecture/design will adapt and react.

I don't need to give you a long narrative. I have it ALL on a .txt file and an accompanying Visio/jpeg.

If you read the Notepad document (please read it all, as I have everything on there you need to know), it explains everything in terms of the scenario, routing methodology, design, etc. I kept it very straightforward.

And the drawing shows you a visual of all that.

I really need a sanity check from someone with good routing experience.

Are the scenarios I present and what I think the reactions will be correct?

Thank so much ahead of time...


I have this problem too.
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Giuseppe Larosa Sun, 06/29/2008 - 05:46


I understand you don't want to have a BGP session with vendor = service provider

however, a BGP session between the two sites of company A wouldn't help in your scenario ?

Best regards


lamav Sun, 06/29/2008 - 06:34


No, BGP isnt an opton for the vendor.

Anyway, that has nothing to do with what I am asking everyone on this board.

Thanks anyway


Giuseppe Larosa Sun, 06/29/2008 - 11:20

Hello Victor,

I was suggesting a BGP session between customer "company A" routers with static routes used just to allow the setup of the BGP sessions.

By the way, looking at your network diagram I don't understand your static routes.

You show a NAT pool of 172.27.64/27 defined on vendor router with the NAT boundary on link between vendor and company A.

On company A DC1 site I would expect a static route for destination network (the global pool for company A DC2 site) and not a static route for the global pool of DC1 site. I would expect a swap of these static routes for a working network.

NAT is provided on the vendor routers, isn't it ?

Your thoughts about failover look like correct however in the case of failure inside the vendor network you have to wait for the application to fails to detect the problem if a BGP session between DC1 and DC2 were in place you could detect this.

For doing this you sholud move the NAT pools on the customer routers.

If this is not possible I agree this is the only way to manage this.

If vendor could provide an MPLS VPN service the NAT pools could be skipped.

hope to help



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