Aggregation Aggravation

LONDON -- A clash of views over the architecture of next-generation networks was spotlighted today in two keynote speeches by executives of European incumbent carriers at The Future of Telecom – Europe 2005 conference.

In the first keynote, Mick Reeve, group technology officer of BT Group plc (NYSE: BT; London: BTA) pointed to "issues" with Multiprotocol Label Switching (MPLS) and Ethernet, technologies critical to the rollout of IP infrastructure for its 21st Century Network project.

Reeve said it's "unacceptable" that MPLS standards still don't make it feasible to manage paths from end to end in an economical manner. This is because of "penultimate hop popping" -- removing MPLS labels at the edge of the MPLS network before forwarding the data to the user. Removal of the label makes it impossible to trace the route of traffic from the user, to pinpoint problems.

Reeve said it's also "unacceptable" that Ethernet standards still haven't been finalized for "Mac-in-Mac" methods of increasing the number of VLANs it supports, and still don't include vital OAM (operations, administration, and maintenance) functions needed to make Ethernet "carrier class."

Both of these issues have been kicked around for a while. (See MPLS Gets the Management Blues, Ethernet Faces OA&M Challenge, and Carriers Face Ethernet 'Black Hole'.)

The second keynoter of the day -- Sten Nordell, vice president for networks and platforms strategy at Telenor ASA (Nasdaq: TELN) -- said his company had avoided these problems by adopting an architecture different from BT's (see Telenor to Unveil All IP Plan ).

Telenor has eliminated aggregation networks between access points and the edge of the MPLS network. Instead, every user is connected by a dedicated Ethernet connection direct to the MPLS network. As packets only have one place to go, it effectively extends the MPLS network to the user site. "We don't have an aggregation network; we have a pipe," Nordell said. "We've removed complexity from the network."

The same strategy also applies to Ethernet. "Because we're transporting Ethernet directly into the MPLS network, it becomes carrier grade," Nordell said.

Nordell acknowledged that some carriers wouldn't be able to adopt Telenor's architecture "even if they wanted to." The scale of the network or the physical layout might make it impossible. He noted that it looks as though BellSouth Corp. (NYSE: BLS) might be adopting a similar architecture.

Somewhat later, the bar opened and everyone forgot what the fuss was about...

— Peter Heywood, Founding Editor, Light Reading