Overview
* Use IP multicast for backward compatibility.
* Use unicat for one-to-many communication.
* Use IP Sockets for peer-to-peer communication.
Peer-to-Peer Communication Using IP Sockets
* IP sockets provide a simple, high-performance mechanism for transferring messages and data between two applications.
* Clustered WebLogic Server instances use IP sockets for:
– Accessing non-clustered objects deployed to another clustered server instance on a different machine.
– Replicating HTTP session states and stateful session EJB states between a primary and secondary server instance.
– Accessing clustered objects that reside on a remote server instance (multi-tier cluster only)
* Two types of socket reader implementations:
– Native: use whenever possible for performance gains.
– Pure-Java: set reader threads to max open sockets.
* Potential socket usage:
– Normally two
– “Pinned” services require additional sockets.
Cluster-Wide JNDI Naming Service
* Similar to single server instance JNDI tree.
* In addition it stores services offered by clustered objects from other server instances in the cluster.
* Each server instance in a cluster creates and maintains a local copy of the logical cluster-wide JNDI tree.
* Deploy homogeneously to avoid cluster-level JNDI conflicts