The communication between realms in a cluster can be secure (encrypted) or non-secure (non-encrypted). The communication is implemented by defining one or more interfaces on each realm.

Since all realms in a cluster are required to have the same configuration (so that for example if the master realm goes offline, one of the other realms can become the new master), you must ensure that any interface definitions on one realm match the interface definitions on all other realms in the cluster.

For non-encrypted inter-realm communication, you can set up the interfaces to use either NSP (Socket Protocol) or NHP (HTTP Protocol). In general, we recommend you to use NSP rather than NHP for non-encrypted inter-realm communication.

For encrypted inter-realm communication, you can set up the interfaces to use either NSPS (Secure Socket Protocol) or NHPS (Secure HTTP Protocol). In general, we recommend you to use NSPS rather than NHPS for encrypted inter-realm communication.