Redundant Data Center Internet Connectivity – High-Level Design
Yesterday I described the roadblocks you might encounter when faced with a seemingly simple challenge:
In a network with two data centers (connected with a DCI link), ensure the applications in a data center stay reachable even if its Internet links fail.
In the Solutions Corner (a brand new part of my web site) you’ll find a short high-level design document describing the overall solution and listing the technologies you could use to implement it (you might want to watch the video before reading the document).
Additionally on the eBGP speakers in both DC's we advertise the local DC's prefix (say a /21) as well as a the larger /20 that encompass's both regional DC's, allowing both DC's to advertise their specific paths as well as provide a backup path for their partner DC.
to date this has worked excellently, we've maintained 100% up time since this was deployed despite several potentially impactful outages at the ISP, CPE or facility level.
Although more difficult for us to initially configure, we felt there was less risk of changes impacting the communication between the DCs because the ONS configurations are fairly static. Many more people manage our switches, and make changes much more regularly. In my company, I could more easily see someone making mistakenly changing the VRF configuration without knowing what they did.