This protocol fragments messages larger than certain size. Messages are rejoined at the receiving end. This works for both unicast and multicast messages. It is configured in the
FRAG2 sub-element under the JGroups Config element, like so:
<FRAG2 frag_size="60000"/>
The configurable attributes in the FRAG2 element are as follows.
frag_size- Specifies the maximum size of a fragment, in bytes. Messages larger than this value are fragmented. For stacks that use the UDP transport, this value must be lower than 64 kilobytes (the maximum UDP datagram size). For TCP-based stacks, it must be lower than the value of
max_creditsin the FC protocol.
Important
The TCP protocol provides fragmentation, but a JGroups fragmentation protocol is still required if
FC is used, because if you send a message larger than FC.max_credits, the FC protocol blocks. The frag_size within FRAG2 must always be less than FC.max_credits.