Some cloud providers charge you less for traffic over internal IP addresses compared to public IP addresses, in fact, some cloud providers do not even charge a thing for traffic over the internal network (i.e. GoGrid). In these circumstances, it's really advantageous to configure Infinispan in such way that replication traffic is sent via the internal network. The problem though is that quite often you don't know which internal IP address you'll be assigned (unless you use elastic IPs and dyndns.org), so how do you configure Infinispan to cope with those situations?
JGroups, which is the underlying group communication library to interconnect Infinispan instances, has come up with a way to enable users to bind to a type of address rather than to a specific IP address. So now you can configure bind_addr property in JGroups configuration file, or the -Djgroups.bind_addr system property to a keyword rather than a dotted decimal or symbolic IP address:
GLOBAL: pick a public IP address. You want to avoid this for replication traffic
SITE_LOCAL: use a private IP address, e.g. 192.168.x.x. This avoids charges for bandwith from GoGrid, for example
LINK_LOCAL: use a 169.x.x.x, 254.0.0.0 address. I've never used this, but this would be for traffic only within 1 box
NON_LOOPBACK: use the first address found on an interface (which is up), which is not a 127.x.x.x address