nanog mailing list archives

RE: Verizon PSTN continued


From: Sean Donelan <sean () donelan com>
Date: Thu, 9 Nov 2006 15:22:56 -0500 (EST)


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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