JBoss.org Community Documentation

22.7.3. Fragmentation

This protocol fragments messages larger than certain size. Unfragments at the receiver's side. It works for both unicast and multicast messages. It is configured in the FRAG2 sub-element under the JGroups Config element. Here is an example configuration.

	
		<FRAG2 frag_size="60000" down_thread="false" up_thread="false"/>

The configurable attributes in the FRAG2 element are as follows.

  • frag_size specifies the max frag size in bytes. Messages larger than that are fragmented.

Note

TCP protocol already provides fragmentation but a fragmentation JGroups protocol is still needed if FC is used. The reason for this is that if you send a message larger than FC.max_bytes, FC protocol would block. So, frag_size within FRAG2 needs to be set to always be less than FC.max_bytes.