Changes to CLUSTERIP between r3 and r4
'''Loadbalancer Less Load Balancing'''
There's not a lot of information on CLUSTERIP on the Internet for some reason. It's an implementation of an older technique, made easier by an IPTables target extension.
* Flavio's Technotalk on CLUSTERIP [http://flaviostechnotalk.com/wordpress/index.php/2005/06/12/loadbalancer-less-clusters-on-linux/] [http://web.archive.org/web/20070125103802/http://flaviostechnotalk.com/wordpress/index.php/2005/06/12/loadbalancer-less-clusters-on-linux/] [http://www.rkeene.org/projects/info/resources/projects/ipcluster/flavios-tech-talk-on-ipcluster.html]
* "Load Sharing with IPtables and Linux-HA" [http://www.linux-ha.org/ClusterIP]
* Microsoft calls this technique "Network Load Balancing" [http://technet2.microsoft.com/windowsserver/en/library/358b9815-3cd3-4912-a75a-cae85ea8d5ab1033.mspx?mfr=true]
* [LARTC] has a longer explanation of the underlying mechanism [http://lartc.org/autoloadbalance.php3]
* [LARTC] has a longer explanation of the underlying mechanism in their article "How to do simple loadbalancing with Linux without a single point of failure" [http://lartc.org/autoloadbalance.php3]
Only in r3
Only in r4 --> Modified slightly between r3 and r4