Multihoming with BGP
Posted on 2011-03-01
I have a client that does monitoring for alarm security systems. The alarms in the field, which I will call clients, send a UDP packet to a piece of hardware that I will call the alarm server to indicate the alarms. The current solution to build redundancy and failover to the setup, is to add a second server which is connected to a second ISP. The two servers are on the same LAN, but use different default gateways. Clients in the field are set to communicate with the primary server and only use the seconary server if the primary fails. This setup allows us to keep monitoring the alarms if a single ISP fails or and single server fails. However, if the primary ISP and secondary server both fail at the same time, we are not longer able to monitor the alarms.
With a multihomed setup with BGP, I understand that the primary and secondary IP addresses could be reached over either ISPs. If the primary ISP fails, the clients will still communicate with the primary server, but through the secondary ISP. If the primary server fails, the clients will communicate with the secondary server through whichever ISP. While the alarm monitoring only need the two IP addresses, by the time we setup the routers we would still only need 5-10 addresses. Would it be worth while setting this up using BGP?