4.2BSD: rwho and multiple networks

[sanjay Radia]

	The rwhod does a broadcast of the uptime and who-list on all the
networks directly connected to the host. Now, gateway hosts (hosts
connected to 2 or more network) forward packets destined for other networks
if the appropriate information is in the kernel routing tables. They do
not forward broadcast packets as this could cause loops and besides, in
my opinion, the ethernet broadcast packets, by definition,  are destined to
all hosts on a network and not to all hosts on an internet.
I know that some work was done at Xerox on internetwork broadcasting
(by Boggs, I think).
	You might make the rhwod do the necessary "broadcast forwarding" if its
host is connected to multiple networks but again you have to watch out 
for loops (hop counts will not work properly in general depending
upon the topology of your internet).  You could add on the network id of each
net through which a packet passes and then somehow prevent loops.
	Alternately, you could explictly tell certain rwhod's (those at key
nodes on the network) to forward info to other networks. This solution would
require manual intervention each time there is a change in the network topology
and maybe it won't work for certain topologies.
Maybe someone has better ideas.
sanjay
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		sanjay
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