Nortel Networks Ltd. is further enhancing its 8600 Metro Ethernet Routing Switch to meet the growing demand for Provider Backbone Transport (PBT) capabilities, the vendor announced today.

As the leading flag bearer for PBT, a controversial connection-oriented version of Ethernet that's known as Provider Backbone Bridging, Traffic Engineering (PBB-TE) in its Institute of Electrical and Electronics Engineers Inc. (IEEE) standards process, Nortel is keen to keep the technology's profile high.

So while it's busy developing a new PBT-enabled carrier Ethernet product, known as MetroNext, the vendor is adding new features to the 8600 switch that is being deployed by PBT's main carrier supporter, BT Group plc (NYSE: BT; London: BTA). (See Nortel Preps New PBT Switch and BT Goes Live With PBT.)

One key new feature is support for E-Tree, a point-to-multipoint topology being standardized by the MEF . E-Tree is expected to come in handy for delivering IPTV services, while some, including John Hawkins, a carrier Ethernet marketing manager for Nortel, believe it's also suitable for Ethernet-based wireless backhaul and DSLAM backhaul.

E-Tree is a relatively new development, with Hammerhead Systems Inc. among the few companies to detail support for the topology, both in PBT and Multiprotocol Label Switching (MPLS). (See Hammerhead Unveils PBT Smarts.)

Nortel says its E-Tree implementation supports dual homing, a way of giving the tree's root a backup node without having to build an entire redundant tree in the network.

Nortel is also launching new interface modules for the 8600, adding small-form pluggable (SFP) support and an XFP module with three 10-Gbit/s Ethernet ports. New network processors will help some of the modules support 60,000 virtual private networks (VPNs) apiece, up from 30,000 in the previous generation.

The 8600 enhancements are set to be available in the first quarter of 2008.

Nortel is still also working on getting PBT added to its Optical Multiservice Edge 6500 platform. Hawkins says it's still on the company's to-do list, and could appear next year. (See OME Waits for PBT.)

Nortel's product news comes as PBT continues to attract carrier interest and support from multiple vendors. (See PBT: New Kid on the Metro Block, CESR Sales Crack $500M, BT Goes Live With PBT, and Deutsche Telekom Flirts With PBT.)

Not everyone's a fan, though, as PBT is also attracting very direct criticism from pro-MPLS vendors like Alcatel-Lucent (NYSE: ALU), which gave the still-developing Ethernet technology a verbal kicking at a recent Light Reading Live event in Poland. (See PBT Cost Claims Questioned.)

That event prompted a response from BT, which countered AlcaLu's claims about the cost of deploying and managing PBT. (See BT Counters PBT Claims.)

The cost issue is important, as PBT is being pitched to carriers as a cheap, easy-to-provision transport technology that, operationally, closely resembles SDH. Those attributes, say its supporters, make it an attractive alternative to MPLS in many next-generation network scenarios. (See MPLS: Metro a No-Go?)

Nortel's Hawkins adds to BT's defense of PBT: "The original argument still stands, that an Ethernet management capability is operationally intuitive to a transport person."

Carriers are "having to experiment and stage their rollouts," but that doesn't mean the PBT argument has been disproven, contends the Nortel man.

Nortel also announced two new PBT customers today -- Swiss utility firm groupe-e, and Highland Telephone Cooperative and Southern Light in the United States. The vendor has also added seven more names to its Carrier Ethernet Ecosystem. The new participants are Bay Microsystems Inc. , Broadcom Corp. (Nasdaq: BRCM), Ceterus Networks Inc. , Ethos Networks Ltd. , InfoVista SA , JDSU (Nasdaq: JDSU; Toronto: JDU), and Zhone Technologies Inc. (Nasdaq: ZHNE).

— Craig Matsumoto, West Coast Editor, Light Reading