Verizon PSTN continued

Alexander Harrowell a.harrowell at
Fri Nov 10 09:55:44 UTC 2006

"Centralised switching guarantees QOS!" Keep saying it and it might be true!

On 11/9/06, Sean Donelan <sean at> wrote:
> On Tue, 7 Nov 2006, Chris L. Morrow wrote:
> >> Working with 2 other carriers on a similar issue, response I rec'd was
> >> congestion due to automated political dialers. Not sure if I believe
> >> that or not...
> >
> > you'd think they'd have systems monitoring that and trimming down the
> > 'fat'? or can they do that? (legally I mean, sorta like QOS for the phone
> > network I suppose)
> They can, and do.  But SS7 interconnect battles between carriers are about
> as much fun as peering battles between ISPs, lots of finger pointing and
> blustering and more lawyers. If you lose SS7 links between carriers, and
> there is not enough SS7 capacity remaining, the SS7 systems start
> "flapping" (the SS7 folks probably use a different term, but it gives the
> IP folks some idea of what happens).  It has happened a few times.  I
> expect the SS7 vendors and protocol wizards are thinking up more clever
> ways to address it.
> It has nothing (essentially) to do with the type of calls being made,
> although high call volumes always make any problem worse.  Another time
> it happened was just before Christmas a few years ago, during peak
> shopping time and the dialup credit card authorization numbers (and lots
> of other types of numbers) got jammed up during a SS7 incident as I found
> out doing my Christmas shopping that afternoon.

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