Router for TCP based group comunication (using layer TCP instead of UDP). Instead of the TCP
layer sending packets point-to-point to each other member, it sends the packet to the router
which - depending on the target address - multicasts or unicasts it to the group / or single member.
This class is especially interesting for applets which cannot directly make connections (neither
UDP nor TCP) to a host different from the one they were loaded from. Therefore, an applet would
create a normal channel plus protocol stack, but the bottom layer would have to be the TCP layer
which sends all packets point-to-point (over a TCP connection) to the router, which in turn
forwards them to their end location(s) (also over TCP). A centralized router would therefore have
to be running on the host the applet was loaded from.
An alternative for running JGroups in an applet (IP multicast is not allows in applets as of
1.2), is to use point-to-point UDP communication via the gossip server. However, then the appplet
has to be signed which involves additional administrative effort on the part of the user.
Note that a GossipRouter is also a good way of running JGroups in Amazon's EC2 environment which (as of summer 09)
doesn't support IP multicasting.