From: Howard C. Berkowitz (hcb@gettcomm.com)
Date: Tue Jul 20 2004 - 13:15:52 GMT-3
At 4:30 PM +0300 7/20/04, Dan Shechter wrote:
>Hello all,
>
>I have read somewhere that the 'dialer load-threshold' should be
>configured only on one end, because both side might initiate the
>connection in the same time and the call won't succeed.
>
>Is it right?
>
Let me answer in a more general way. Anytime you have a
connection-oriented function that can be initiated by either end, one
of two conditions is necessary for reliable operation (i.e., without
unresolved collisions)
1. The two ends have different trigger rules for starting the action,
so it is highly probable that one will trigger before the other.[1]
2. The protocol (e.g., BGP session establishment) has a built-in
mechanism for establishing requester-responder relationships in
the event of the collision of simultaneous requests.
[1] It will sometimes happen that, say, you set one side to trigger on
45% outbound link utilization and the other side to trigger on 65%
outbound link utilization, and both ends just happen to hit the same
trigger at the same time.
The simplest answer to this is to observe "life is hard, and then
you die." A more scientific answer says that well-designed functions
have built-in collision resolution, as in #2 above.
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