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Multi Hommed, Multi Site Recommendation

I think I am on the right track here, just want to know from people in the group if I am proceeding in the right direction.

Background: Currently have 2 providers and our own AS from arin. We have a full class c from one upstream provider, and bot providers are broadcastings that subnet.

Issue: We are currently getting ready to replicate our current environment, and the new site and our existing sites are to be redundant with each other.

My solution: Using our current setup and BGP networks, I am thinking I can simply assign the same addresses to the corresponding machines in the new network and have the provider at the hosting center broadcast our subnet from our other provider.

If I am way off base here please let me know, along with any other solutions that might work. I do have the ability to have full class c address blocks from all players.

Thanks in advance!


Re: Multi Hommed, Multi Site Recommendation

This approach can work, but is dangerous if not carefully thought out and managed. The problem comes if both sites are "on-line" at the same time, at which point inbound traffic could end up going to the wrong site. Automating the cutover from one site to the other can be tricky. Some of the issues are discussed in the Disaster Recovery chapter of my book "High Availability Networking with Cisco."

Keep in mind that it is rarely simply a case of turn off the primary and turn on the secondary. You also typically need communications between primary and secondary sites to allow updating. These communications paths must also be part of your design.

Good luck and have fun!

Vincent C Jones

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