North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Verizon outage in Southern California?
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I wonder what ever happened to redundancy? I guess 5 9s (dunno what the going number is) got blown out of the water for them. regards, /virendra David Lesher wrote: > > Speaking on Deep Background, the Press Secretary whispered: > >> >>I'm not completely familiar with the telco jargon. >>Does Tandem mean the same as a local central office, where >>POTS lines terminate at the switch? Long Beach has a population >>of 470,000. The C/Os I know of are: > > > > A "Central Office" switch talks to subscribers aka end-users. > On its backside, it talks to other CO's and tandems. Time > was, that was also VF copper pairs, but it's long since all > DS1 and up..... > > A tandem is a switch that talks not to subs, but only to CO's. In > days of old, when a {dialup} call went to the other side of town, > chances are it went you-yourCO-downtown tandem-joesCO-joe. {copper > all the way...}. > > A tandem was always housed in large CO building, but might have > been ATT's vice the operationg company, etc... > > But ESS's and ""classless switching"" and massive expansion of the > plant really muddled the picture. An ESS could be both a CO switch > [for multiple prefixes and even multiple NPA's..] AND act like a > tandem.. And oh, the actual "line cards" can be remoted 100 miles > away in a horz. phonebooth box alongside the road in Smallville.... > with DS1's/OC coming back. > > My guess is a DACS, a cross-connect point that is an software-driven > patch panel, lost its marbles. [engineering term of art.....] > A DACS could have dozen->MANY dozen DS1/DS3/OC-n going hither > and yon. Some will be leased circuits. Others will be the CO trunks > going from one switch to another. It may/may not have muxes internal, > so that what arrives on a DS1 leaves in a OC96.. > > I note it went down at 2:20 AM. That SCREAMS software > upgrade/cutover. What's to bet GEE, no...VZEEE, was doing just > that and there was a major ohshit. > > Sean noted a long while back that somehow, DACS crashes always > seem to take hours to recover. Maybe the backups are on Kansas > City standard tapes, I donno.. but this sounds like that.. > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.5 (MingW32) Comment: Using GnuPG with Thunderbird - http://enigmail.mozdev.org iD8DBQFDVoJXpbZvCIJx1bcRAstJAJ0dnrQL1P2QJyxNU3r0T/X8g9fukQCgnm/N yW5EvW7gI3gfjY7XSozyMds= =ocNd -----END PGP SIGNATURE-----
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