What is this ?
Check the Multiplexer documentation (section 6.3) for details.
Using the Multiplexer in JBoss
If you want to play with the Multiplexer; I've uploaded a SAR to www.jgroups.com/Multiplexer.sar. This can also be created by downloading the JGroups source and executing target multiplexer-service (./build.sh multiplexer-service). The Multiplexer.sar will then be placed into ./dist.
I tried this with jboss-4.0.x (so the latest from the 4.0 branch).
(You can create the SAR yourself by calling ./build.sh multiplexer-service in JGroups; the SAR will be placed into ./dist)
Copy the Multiplexer.sar to your /deploy dir
Find the jgroups:name=Multiplexer in jmx-console
Find and execute the method createMultiplexerChannel(), use "fc-fast-minimalthreads" or "tcp" as first arg, and any other value as second (appl ID). This is from stacks.xml. (If you click on dumpConfig(), it'll dump all stack names listed in stacks.xml)
Go back to the MBean
Click on dumpChannels(): you'll see the channels plus registered applications. Note that you cannot register the same app twice
Go back to the agent view, find the "jgroups" domain. You'll see that we've got (1) the Multiplexer, (2) all channels and (3) all protocols. Whether or not you want to expose protcols is governed by the ExposeProtocols attribute
Go back to "jgroups:name=Multiplexer"
Click on destroy() / or remove the Multiplexer.sar from /deploy
You'll see that the agent view doesn't list any channels/protocols anymore