Answer:   A Universal Messaging Realm is the name given to a single Universal Messaging server. Universal Messaging realms can support multiple network interfaces, each one supporting different Universal Messaging protocols. A Universal Messaging Realm can contain many Channels or Message Queues.
Zones: Zones provide a logical grouping of one or more Realms which maintain active connections to each other. Realms can be a member of zero or one zone, but a realm cannot be a member of more than one zone . Realms within the same zone will forward published channel messages to other members of the same zone, if there is necessary interest on corresponding nodes.