Anycast: IP-SLA HOWTO

The complete configuration necessary to implement anycast DNS using Cisco IP SLA, though it’s a little weird without the background.

Anycast: DGRAM vs. STREAM

For internal anycast services, it doesn’t really matter if it’s using TCP or UDP, so long as your routing protocol fails over quickly.

For internal services, you probably want to have them fail over between sites. Dynamic routing protocols will let you do that.

If you use a loopback interface for your service, you can share the IP address between two different servers, even on the same LAN.

A nifty hack that’s possible in IP networks is the ability to share an IP between servers thousands of miles apart.

Anycasting is a way to scale geographically by having multiple servers sharing the same IP address.