JGroups Workload Communications in a Clustered Installation

Communication among cluster nodes about the workload of each node helps provide business process load balancing. You have a choice between multicast communication (which services all requests with a single stream of data) and unicast communication (which services each request with its own stream of data).

This method can use either IP multicast communication or TCP unicast and multicast communication. The unicast method lets one node communicate directly with another node, without the communication being distributed across more than one node (as with multicast).

You can use TCP when IP multicast is restricted because of security reasons or when IP multicast is a bottleneck to providing cluster support across a WAN for geographically distributed clustering.

You can choose between UDP and TCP during configuration. It is strongly recommended to use TCP communication, but the decision to use UDP or TCP depends on several factors, including the company's security policy (some disable UDP). For more information on UDP and TCP, see the JBoss.org Community Documentation page: http://www.jgroups.org/manual/html/user-advanced.html.

JGroups is used in cluster communication for broadcasting the business process load factor across all nodes in a cluster. It also can be used for workflow context distribution for load balancing. JGroups provides for reliable communication and group membership management, including notification and handling of new memberships, departing members, and failure detection and broadcasts. The underlying protocol can be switched during installation and configuration without compromising on the features of group membership management and communication. It also provides tunnelling over the firewall, which expands the cluster communication support for clusters on geographically distributed networks.

The JGroups protocol property settings (like type of protocol and ping interval) are managed in the jgroups_cluster.properties file. Multiple JGroups channels can be configured and managed in Sterling B2B Integrator by supporting multiple protocols.

The default protocol set for JGroups for business process load balancing information is IP multicast. Workflow context distribution is TCP unicast.

In addition, if you are using TCP for both property_string and distribution_property_string, the initial_hosts list for TCPPING should contain all hosts in the cluster.