BEA Weblogic Interview Question:

When should I use multicast subscribers?

Submitted by: Administrator

Multicasting enables the delivery of messages to a select group of hosts that subsequently forwards the messages to multicast subscribers. The benefits of multicasting include:

* Near real-time delivery of messages to host group.
* High scalability due to the reduction in the amount of resources required by the JMS server to deliver messages to multicast subscribers.

Note: Multicasting is only supported for the Pub/sub messaging model.

For an example of when multicasting might be useful, consider a stock ticker. When accessing stock quotes, timely delivery is more important than reliability. When accessing the stock information in real-time, if all, or a portion, of the contents is not delivered, the client can simply request the information be resent. Clients would not want to have the information recovered in this case because by the time it is redelivered it would be out-of-date.
Multicast messages are not guaranteed to be delivered to all members of the host group. For messages requiring reliable delivery and recovery, you should not use multicasting.
Submitted by: Administrator