Typically in a WAN environment clients at a particular location are primarily interested in topics for which their local Distributed Cache is the “home” Distributed Cache (that is, the Distributed Cache that is the definitive repository for messages on those topics). However, these messaging applications may occasionally wish to fetch messages for topics that are “homed” on other Distributed Caches in the network.
The Global Caching feature enables client applications that are operating in a WAN environment to request and receive messages for topics, as usual, from their local Distributed Cache or Cache Cluster, regardless of whether those messages are cached locally or in a Distributed Cache that is geographically distant. The requesting clients do not need to know where in the network a particular topic is being cached or where the cache response comes from.
For more information on the Global Caching feature, refer to Using Global Caching.