Hop

[Mal Lansell <mal@xxxxxxxxxxx>]

So I was looking at the idea of an xPL Router, when Ian pops up and says
"hey, we wrote one", but I the idea still rumbled around my brain
for a
bit.  After a bit of design, I was left wondering how to stop messages
looping around between routers.

Looking at the existing app, it appears to hash the received message,
and then not retransmit any that match any of the hashes in its list.
But I thought that was what the hop was for - if it is > 1 then don't
retransmitt.

Then I realised, what if there is an rs232 network connected? - the xPL
messages from that will have a hop of 2 (1 when sent, +1 when moving
from rs232 ro udp).  That led me to wonder just what is the point of the
hop count - if there is more than one app on the PC that can increment a
hop, then without knowing who did it, how it can be of any use...?

Mal