Multicast traffic considerations with multiple IBM Business Process Manager V8.5 environments in a Flat Network
Nakul Bharade 270004XHV7 Visits (2015)
This blog covers the multicast traffic considerations with multiple IBM Business Process Manager (BPM) V8.5 environments in a flat network. It also covers the steps that must be taken to address these considerations.
For the sake of this discussion, we can assume that a customer is on a WebSphere Application Server Network Deployment V8.5.x.x (WAS ND) and a BPM Standard V8.5 two node three cluster topology.
Multicast is a technique for one-to-many communications over an IP infrastructure in a network, where a host can send data to a group of hosts without knowing who are the members of the group. In WAS ND, the multicast address is used by the BPM cluster members (application, support and messaging) and node agents to discover one another on startup. This multicast address is a logical address, therefore it is not bound to any physical address and will not be the same as the host name (or IP address) of the host on which the node agent is executed. In WAS ND, multicast host addresses must be within a special range (188.8.131.52 to 184.108.40.206) defined by the IP standards and must never carry a host name value. The default value for the WebSphere node agents is 220.127.116.11.
By default, all BPM environments (Development, Test, Production etc) installed in a flat network come with a multicast address of 18.104.22.168. This means that in a flat network, multicast messages from cluster members and node agents in one environment will also be routed to members of the other environments. This may lead to unintended consequences. To mitigate this issue, a unique multicast address must be assigned to each BPM environment. The example below shows the steps involved to assign a multicast address of 22.214.171.124 to a WAS ND cell in a BPM environment during the product installation and deployment environment configuration phase.
In the serverindex.xml file, update the host IP address associated with port NODE
To change the multicast address in an existing BPM environment, follow steps 4, 5,6 and 7 above.