Sample Scenario
Internal failover router

Some larger web-sites use advanced hardware routers internally to distribute load between web-servers, and to provide failover functionality (the router detects failed web-servers, and does not route traffic to them). The only problem is that this router is in itself a vulnerability. If the router or the connection to it fails - the web-site is effectively down, no matter how many servers are on the inside of the router. And since the router and the servers are all in one geographical location, everything is still vulnerable to the same disasters (floods, fires etc.):



Simple Failover can correct this by re-routing traffic to an external web-server if the primary location should be down: