PBB Steals the Stage

Two years ago, Nortel Networks' newly minted metro Ethernet division made a splash at the Globalcomm trade show by introducing provider backbone transport technology in its carrier Ethernet switch. A lot has changed since then: Globalcomm is no more; the metro Ethernet division is up for sale; and as for PBT, well, that's a longer story.

PBT, the point-to-point tunneling technology for connection-oriented Ethernet transport, is actually a subset of an older technology, provider backbone bridging (PBB). (PBT is essentially PBB with some of the functions turned off.) Nortel's embrace of PBT led a fast-emerging cult of like-minded equipment vendors — including Extreme Networks, Fujitsu Network Communications, Hammerhead Systems, Meriton Networks and Soapstone Networks — to follow suit, introducing their own PBT gear and igniting a storm of interest across the industry, as well as a formal effort to standardize the technology under a new name that highlighted its roots: PBB-TE (for “traffic engineering”). Ironically, it is the technology's older sibling, PBB, that seems to be getting more attention these days.

Alcatel-Lucent, an established vendor of MPLS gear in metro networks (the champion to PBB-TE's challenger), stuck to its guns and shunned the PBB-TE game. But this summer it added PBB to its 7450 Ethernet edge switch, pairing it with MPLS-based virtual private LAN service in metro networks. In August, Foundry Networks added PBB to its own gear, though in a manner less dependent on MPLS than Alcatel's solution.

Perhaps most notably, the only U.S. Bell carrier to weigh in favorably on the topic, Verizon, has voiced much more interest in PBB than PBB-TE. This summer Verizon began lab-testing Nortel's Metro Ethernet Routing Switch 8600 to see if its PBB capabilities could help scale and diversify the carrier's switched Ethernet services.

“We're in the MPLS pseudowire world until further notice,” said Mark Wegleitner, chief technology officer for Verizon. “We continue to look at PBT, but it's not being actively planned for in our network. We do have great interest in PBB because we have scalability and other issues we think PBB can help us with.”

Add to that the skepticism expressed by Pieter Poll, chief technology officer for Qwest Communications, regarding whether PBB-TE is cheaper or simpler than MPLS in the metro, and it's safe to say the U.S. Bells are not carrying PBB-TE's torch today.

Still, because the 8600 is capable of both PBB and PBT (on the client and trunk sides, respectively), Nortel can potentially claim that it has a foot in the door at Verizon — a chance to eventually sell the carrier on turning up PBT on the other side of those switches. (Fujitsu can probably say the same; its newest transport platform, the Flashwave 9500, which Verizon deployed this year, will be PBB-TE-capable early next year).

Of course, PBT has been adopted already (as many new technologies initially are) by some U.S. Independent carriers, including Dakota Carrier Network and Frontier Communications. So two years from now, who knows how the story will have changed?