Hot Site BGP Setup

[plexus]

Here is the scenario: We have our main site with 2 ISP connections, our own /24 external subnet and AS number. We are running BGP on the router connecting us to the ISP's. We are looking to bring up a "warm" site for our DR Plans. What is the best choice for setting this up? We are considering either having the backup site use the same subnet as the primary with route suppression or we can use our /28 subnet (new for hotsite link) and use a DNS redirection approach. Any suggestions?

[steven-dunn]

If you keep the same subnet you won't have to worry about changing DNS when you need to. You can prepend as path hops to your BGP route advertisment to force your data to your live site. When that site goes down, your backup site will take over.

If the site is going to be "warm", you will probably have a lot of day to day admin work to do on firewalls, servers, relays,etc to keep them in line with the live site, so if you are using identical subnets, management may become an issue. If you don't have too many DNS entrie's, use the redirect.

DR has a lot of conciderations, you will find setting up the network will be the easy part. Find out what the business needs and how fast they need it.

[plexus]

Your answer is what I thinking. Only the external subnet is going to be identical at both sites. We will have the backends of each site in their subnet so management should not too big of an issue there. It is for my company and we are talking about a month or so for this to be ready.

Thanks for the help.

[wkumari]

You may want to consider doing conditional advertisement instead of just prepending lots of times if you need to ensure that the DR site does not receive traffic while the main one is up. While AS Path is near the top of the decision process, some traffic does sometimes "leak" to prepended paths. If the DR site isn't announcing the space (untill needed) you will not have this problem...

Warren.