RE: Callback Profile

> 3) The user peer sends a single message on the
> callback channel to the provider peer identifying 
> the transport mapping details to use for the callback
	If a callback mechanism is defined, it would be useful if the
callback initiator was able to also pass a token (call it a "calling
card") that was to be returned as part of the callback. Data in the
calling card would be used to facilitate the process of doing rendezvous
with the specific application session that had requested the callback.
The data in the calling card could also be used to augment the security
of the connection.
	An application for callback that might be a bit more uplifting
than avoiding license restrictions would be load balancing. This might
have application in solving the problem of having multiple Apex relays
in a single administrative domain. i.e. someone wishing to connect to an
array of relays would do so via a callback request to a load balancing
server. The load balancing server would then request that the best
available relay establish a connection with the endpoint. (This would
address some of the issues that led me to suggest a Beep and/or Apex
"redirection" option in the past.)

		bob wyman