Re: Dialup congestion and winter weather (fwd)

[Mark Milhollan <mlm () ftel net>]

Jeff Mcadams writes:

> its been our experience that once all of the channels on all of the
> available PRI to the ISP are in use, the telco will generate an all
> circuits busy type of response as the PRI are trunk-side, so the
> switches typically treat them as inter-switch trunks being filled, not
> end lines to the ISP being full.

As always YMMV.  The result is affected to a great extent by
provisioning.  Which is obvious and yet hasn't been mentioned.

One way causes a call setup request to be sent even though the switch
knows that there are no available B channels, which permits the terminal
to make it's own decision as to the disposition of the call, e.g.,
refuse it with cause code 17 which _should_ cause some switch in the
call path (the originating one usually) to generate a normal busy tone.