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Optical/IP

In Qwest Outage, ATM Takes Some Heat

A nationwide outage on the ATM network of Qwest Communications International Corp. (NYSE: Q) has thrown so-called "legacy" ATM switches into the spotlight, once again.

The outage occurred between Wednesday and Thursday of this week, affecting OC12 (622 Mbit/s) and OC3 (155 Mbit/s) links on Qwest's high-speed ATM network. Those links are reportedly based on GX 550 ATM core switches from Lucent Technologies Inc. (NYSE: LU). And members of the North American Network Operators' Group (NANOG) mailing list were abuzz with complaints on Thursday. "I'm betting on a bungled software upgrade or something similar," wrote one.

Neither Lucent nor Qwest returned calls about the outage at press time.

But one network engineer at a large West Coast facility said his network was out all night between April 4 and 5, and he thinks the Lucent switches may be to blame. "With those 550 ATM switches, if one acts up it sends a ripple effect through the rest of the network," he says. Outages tied to the switches have been reported before. The engineer says Lucent's had problems with the inter-switch PNNI (private network-to-network interface) code that coordinates the flow of traffic between switches. Qwest's been adjusting the code, he says, and the carrier told him they'd replaced it on the Lucent switches a week or so ago to fix problems.

The outage reportedly did not affect Qwest's IP network at all, since that portion of the net uses packet over Sonet (POS) for high-speed networking, not ATM.

Follow-up discussions on NANOG suggest that Qwest's older, pure ATM gear is being eyed for revision and replacement (see ATM: Over and Out?). This may open the door for several startups, including Équipe Communications Corp. and WaveSmith Networks Inc., that are marketing switches that could replace such gear and cope better with quality-of-service issues in packet-based nets.

- Mary Jander, Senior Editor, Light Reading http://www.lightreading.com
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netskeptic 12/4/2012 | 8:35:25 PM
re: In Qwest Outage, ATM Takes Some Heat MPLS is just a new buggy and it is in no way better than old one. IMHO.

Thanks,

Netskeptic
Betelgeuse 12/4/2012 | 8:35:25 PM
re: In Qwest Outage, ATM Takes Some Heat Wouldn't Qwest be better off replacing the ATM gear with MPLS based packet technology? If your buggy broke down after the car had been invented, wouldn't it be better to by a car? You know the horse is going to die soon anyway.

Betelgeuse
yit 12/4/2012 | 8:35:25 PM
re: In Qwest Outage, ATM Takes Some Heat Are there any major providers that truly have MPLS rolled out throughout their backbones? I've talked to quite a few who have MPLS, but it is mostly a few LSRs (aka Juniper Boxes) in a small area of their network.

So how many backbones have been turned over to MPLS?
freedman 12/4/2012 | 8:35:22 PM
re: In Qwest Outage, ATM Takes Some Heat MPLS may not be the answer since there is no track record of a large scale MPLS network. Even IP network could encount the same problem. The issue is how to achive stability of a large network. This is no a layer-3 or layer-2 protocol issue, not even a routing issue. It involves routing and system design.
Betelgeuse 12/4/2012 | 8:35:22 PM
re: In Qwest Outage, ATM Takes Some Heat A few providers currently have or are planning to deploy MPLS. Right now it is mostly LSR. Like all the other protocols in the past Frame Relay, ATM, etc it will take some time for people to adopt.

I've been through a number of these migrations in my career starting with X25. Then they invented Frame Relay and tried to put Frame Relay code on X.25 switches and that didn't work too well so they built Frame Relay switches. Same thing happened with ATM on Frame Relay switches. Now they are putting MPLS code on best effort routers and that won't work too well.

MPLS is start to take off when real MPLS switches hit the market.

Betelgeuse
whineceller 12/4/2012 | 8:35:18 PM
re: In Qwest Outage, ATM Takes Some Heat The same Lucent (Cascade) gear took out Worldcoms network for over a week in the late summer of 1999. Questions :

What is out in the market now that can do the job of these switches?

Isnt it ironic that many of the engineers that developed the Cascade gear are at Sycamore. Sounds from the posts that this gear has its own problems.


These outages are true opportunities for some new upstart to step up and offer a better solution than Lucent is offering. I see a lot of slams but not a lot of we got the replacement product now posts.
lu-alum 12/4/2012 | 8:35:16 PM
re: In Qwest Outage, ATM Takes Some Heat "What is out in the market now that can do the job of these switches?"

By the sound of the article, WaveSmith and Equipe.
fk 12/4/2012 | 8:35:15 PM
re: In Qwest Outage, ATM Takes Some Heat Neither Wavesmith nor Equipe has a box in general availability. I don't know that either company is in so much as beta testing at this point.
freedman 12/4/2012 | 8:35:15 PM
re: In Qwest Outage, ATM Takes Some Heat This happened in other large networks many times before. It could happen to voice, IP, FR and ATM. None can say it will not happen to MPLS or lamda switch. It is part of a large network. One can prevent it to happen often, but won't total eliminat its happenning.
_____ 12/4/2012 | 8:35:11 PM
re: In Qwest Outage, ATM Takes Some Heat http://www.lightreading.com/do...
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