Ascend Archive
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Re: (ASCEND) Max-4000 E1/T1
At 01:03 PM 4/20/98 +0200, Andre Beck wrote:
>If you by "quiese" mean to signal to the telco that an E1 is currently
>inoperative and the telco should refuse calls which otherwise would
>be routed to this PRI (or route them to another PRI if the failed one
>is part of a "bundle"), I would see at least two ways to do that:
>
>1) Signal L1 loss. The E1 can do that, see G.704 and the RAI (Remote Alarm
> Indication) bit in TimeSlot 0. I'm pretty sure the telco will notice
> when we would send RAI and would itself go to AIS until we clear the
> situation. Just going to send AIS would be as effective, IMHO.
>
>2) Drive down L2. As long as L2 is not in sync (after a SABME) the telco
> should not count the PRI as operative. I dunno whether it is easy to
> cleanly shut down L2 so the telco notices, but I expect that there
> is one way or another.
I don't believe that's quiescing. That's taking the line down. Quiesce
means to take the line down gracefully without affecting users. So you
prevent new calls from coming in. You wait for the existing calls to complete.
The methods above are not a standard way to do anything and different
switches may behave differently. National ISDN (USA) has a standard method
for sending service messages to the switch to quiesce. ETSI NET 5 doesn't.
>This is, AFAIK, impossible. The switch is the final location where state
>is kept of which Bs are allocated and which are not. I don't expect that
>there would be a way to trick this. Actually signalling L2 or L1 down is
>the clean way. The big question is whether the telco interprets this in
>the correct way (switches are computers running software, too...).
As I said earlier, SS7 is a usable method and it is a world-wide standard.
Matt Holdrege http://www.ascend.com matt@ascend.com
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