Cisco Tracks PBT Standards Process

PBT, the controversial new flavor of Ethernet, is on the first rung of the standards ladder and is attracting attention from Cisco

December 14, 2006

5 Min Read
Cisco Tracks PBT Standards Process

PBT (Provider Backbone Transport), the new Ethernet flavor championed by Nortel Networks Ltd. and BT Group plc (NYSE: BT; London: BTA), is on the first rung of the standards ladder at the Institute of Electrical and Electronics Engineers Inc. (IEEE) and is under examination by a number of other industry bodies.

The news is important for PBT's supporters, as becoming a standard will help legitimize the technology in the eyes of carriers and vendors alike. It will also rile some companies, particularly Alcatel-Lucent (NYSE: ALU), that don't want PBT to gain any market credibility, as they have rival technologies to sell. The main direct rival to PBT is Transport MPLS, or T-MPLS.

So what's all the fuss about? PBT is a new brand of Ethernet that strips out some of the technology's inherent complexity and enables service providers to create a managed, traceable, point-to-point Ethernet tunnel across a network that offers Sonet/SDH-like performance. As a result, the OA&M (operations, administration, and maintenance) attributes are very familiar to carrier operations staff, so it's a technology they should feel comfortable with and confident about deploying and managing. (See BT Likes Nortel's New Ethernet Flavor and PBT Means What?)

Those attributes have attracted the attention of a number of carriers. BT has been the most vocal in its support, working closely with Nortel, but BCE Inc. (Bell Canada) (NYSE/Toronto: BCE) and Verizon Communications Inc. (NYSE: VZ) have also expressed an interest in PBT. (See BT Rethinks 21CN Core Strategy.)

And that recognition has led more vendors, including Siemens Communications Group to promote the technology. And now Cisco Systems Inc. (Nasdaq: CSCO) is showing interest and believes the technology has some potential. A spokeswoman says Cisco believes "there are plenty of options to do what PBT does," but Cisco will monitor the Ethernet technology's progress through the standards bodies, "and we'll be adhering to the resulting standards. We're tracking it."

Like Cisco, the carriers want a technology that's standards-based. So with BT so keen on Nortel's story, the operator has been helping the vendor get PBT recognized by the IEEE.

Nortel's director of carrier Ethernet in Europe, Mervyn Kelly, says the vendor's strategy has always been to get PBT standardized as quickly as possible.

"We want it to be widely adopted, so we are pushing it through the IEEE as fast as we can," says Kelly. "Sure, it'll allow other vendors to catch up with us, but if the technology isn't adopted by other companies then it won't get taken up [by carriers]. It's not in our interest to be the only guys out there deploying it."

So what has been the process at the IEEE? Kelly says Nortel and BT "socialized PBT" at the IEEE about 12 months ago, again in July, and then in November submitted it for a "formal agreement to proceed" vote, which was passed with a high majority, with no votes against and just a few abstentions.

Now PBT is in the PAR (project approval request) stage, and is referred to in IEEE documents as PBB-TE (Provider Backbone Bridge Traffic Engineering). There will be a further submission in February 2007 for the "formal agreement to proceed" part of the process.

Once that agreement is in place, "it's hard to tell how long before the technology will be standardized," but, Kelly says "the rule of thumb is about a year" at the IEEE.

The Nortel man says PBT is not rocket science. "There's no actual new technology, which makes it safe and risk free for carriers," he says. "Essentially, two things are being examined in the IEEE standards process. The first is a process -- how to use existing Ethernet technology, including VLAN identifier plus destination address" to create a deterministic path for the Ethernet tunnel.

Second, says Kelly, "it's standardizing a method of switching off the 'broadcast unknown' feature in Ethernet. There's currently no standard way of doing that."

But the IEEE is not the only standards body looking at PBT. According to Kelly: The TM Forum has a work item looking at the OSS requirements for PBT; the Broadband Forum has been presented with information for consideration by vendors that might want to incorporate PBT into their DSLAMs; there's an Internet draft paper with the Internet Engineering Task Force (IETF) to look at how GMPLS would manage PBT (see PBT: Stray Thoughts); and BT has submitted information to the International Telecommunication Union (ITU) 's Study Group 15, which looks at optical and other transport network infrastructures. "The ITU is doing a lot of stuff around Ethernet OA&M that is directly relevant to PBT," says Kelly.

Meanwhile, PBT continues to evoke passionate debate among vendors. At the "Future of Optical Networking: Europe," a Light Reading conference held in London earlier this week, a panel of vendor executives was asked whether they thought PBT was more suitable for carriers than T-MPLS.

Massimo Leo, director of product marketing in the optical multiservice networks division of Alcatel-Lucent, was most forthright. "T-MPLS is better. That's it," he said. Though he did elaborate after the laughter subsided, saying that T-MPLS is already a standard at the ITU, "which is the proper place to do transport standards," and backed by the IETF, "which is the proper place to do packet standards."

He added: "PBT was initiated by Nortel, and now there are a number of vendors staring through the window to see what will happen."

One of those technology peeping toms is Ciena Corp. (NYSE: CIEN). Marketing director Vinay Rathore said Ciena "hasn't taken sides" because it's waiting to see what carriers want. "I see an advantage to PBT because of the simplicity of the technology, but both [PBT and T-MPLS] appear to do exactly the same thing."

Nick Cadwgan, director of product marketing at Meriton Networks Inc. , said his company can "see the need for a connection-oriented methodology. The IEEE is the home of Ethernet, and this [PBT] is a way of making Ethernet more carrier-grade. It's starting down the standards path now, but the customers will decide."

But Meriton's not throwing its weight behind just one camp. "PBT will actually use some of the exact same attributes as T-MPLS. We intend to support both," said Cadwgan.

— Ray Le Maistre, International News Editor, Light Reading

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