Ethernet equipment

Vendors Clash Over PBT

PBT (Provider Backbone Transport) has solidified its reputation as the telecom industry's most controversial technology, with its supporters and detractors jostling for the chance to talk up or shoot down its potential. (See PBT: New Kid on the Metro Block.)

With most of the carrier community watching from the sidelines, equipment vendors have argued vociferously about the validity of PBT (the pre-standards connection-oriented flavor of Ethernet) as a technology worthy of commercial deployment, with the pro- and anti-PBT camps clashing again at the Carrier Ethernet World Congress in Geneva last week. (See PBT vs MPLS: Round VII.)

There, Nortel Networks Ltd. , Ciena Corp. (NYSE: CIEN), Extreme Networks Inc. (Nasdaq: EXTR), Meriton Networks Inc. , and Nokia Networks were PBT's most vocal supporters, while the leading MPLS vendors -- Alcatel-Lucent (NYSE: ALU), Cisco Systems Inc. (Nasdaq: CSCO), and Juniper Networks Inc. (NYSE: JNPR) –- were the technology's major detractors in presentations and panel sessions. (See Nortel Touts Ecosystem and Extreme Tests PBT.)

That division exists because PBT is regarded as an alternative to MPLS in metro networks, a tension highlighted in the latest Light Reading Insider, MPLS vs. PBT: The Empire Strikes Back.

In that report, author Simon Sherrington finds the MPLS vendors under pressure from advances in Carrier Ethernet technology, and having to fight hard to "justify the role of their technology in metro and access infrastructures." (See MPLS: Metro a No-Go?.)

The end result, he feels, is that the emergence of PBT as an option for carriers will drive MPLS innovation and new product development -- something that will ultimately have a positive impact on the router vendors.

Validating multivendor deployments
Pressure on the MPLS vendors intensified in Geneva, where German test facility European Advanced Networking Test Center AG (EANTC) replicated a metro and access network using technology from 24 different vendors. (See Hammerhead Demos PBT, WWP Combines MPLS, PBT, RAD Plays Ethernet Test Role, Gridpoint Plans PBT, Soapstone Goes to CEWC, and TPack Talks Ethernet.)

The demonstration network showed how Ethernet services could run end-to-end across network clouds that were using three different transport and aggregation technologies –- MPLS, PBT, and Transport MPLS (T-MPLS), a stripped down version of MPLS that is similar in nature to PBT. (See EANTC Preps MEF Demo.)

The resulting white paper is available at EANTC's Website..

The challenge set by constructing that test network, notes EANTC managing director Carsten Rossenhoevel, was "to interconnect the three metro clouds to an MPLS core" and run services across the clouds. "Interworking between MPLS and PBT was more or less seamless," says Rossenhoevel.

Having conducted numerous network tests involving many fixed and wireless technologies previously, the EANTC man was surprised by the success attained with a non-standard technology. "Successful interoperability with PBT at such an early stage is very reassuring," he says. "This has been a milestone" for the technology.

Independent evidence that PBT and MPLS can co-exist will be reassuring for carriers looking to deploy the new flavor of Ethernet, and none more so than BT Group plc (NYSE: BT; London: BTA), the one major carrier to have thrown its weight behind PBT.

BT has worked with Nortel on developing PBT, is involved in the standards development work at the Institute of Electrical and Electronics Engineers Inc. (IEEE) , has already deployed PBT in Italy, and is working towards deployment in the U.K. (See BT Goes Live With PBT.)

PBT survey reveals carrier indecision
But while the pro-PBT camp has gathered increasing support, and other major carriers are known to be checking out PBT's potential, the technology is still regarded as a risk by many carriers, while vendors with PBT solutions admit that the current interest shown by operators is largely based on curiosity. (See Deutsche Telekom Flirts With PBT, Nortel Lands More PBT Action, and Verizon Preps God Box RFP.)

A survey of carriers conducted by Synergy Research Group Inc. shows that a vast majority, around 70 percent, are "uncertain" about whether they might deploy PBT, while less than 25 percent stated they were definitely interested in deploying the technology. A small percentage, less than 10 percent, had no interest in PBT at all.

Synergy's research showed that the lack of a standard was PBT's major negative. The technology is currently going through the standards process at the Institute of Electrical and Electronics Engineers Inc. (IEEE) , where it is known as PBB-TE (Provider Backbone Bridging - Traffic Engineering), but is not expected to be ratified until some time in late 2008 or during 2009.

In the meantime, PBT continues to attract further vendor support. (See Ciena Falls in PBT Camp, Bay Adds PBT, and Lightstorm Charges Into Ethernet.)

— Ray Le Maistre, International News Editor, Light Reading

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