World Wide Packets Embraces PBT

It looks like Nortel and its customer BT are no longer alone in embracing PBT, or provider backbone transport. World Wide Packets today announced that its LightningEdge 311v platform now supports PBT.

The LightningEdge is a Layer 2 VPN platform that also supports transparent LAN services delivered over Ethernet or over MPLS, but World Wide Packets said that “with the addition of PBT, the LE-311v will simplify the network and enable service providers to drive down the overall costs of deployment which allows for the generation of new revenue by offering optimal services at a fraction of the cost.”

PBT, which is a new take on carrier Ethernet aimed at addressing requirements of transport networks, “provides a means of traffic engineering the network so paths through the Ethernet cloud can be preconfigured (similarly, protection paths can be pre-configured). The result is predicable, resilient behavior from a packet network that is based on Ethernet only and therefore enjoys similar cost advantages,” John Hawkins, senior marketing manager for carrier Ethernet at Nortel, once the sole vendor behind PBT, told xchange in a recent interview. The need for spanning tree protocol thus goes away for those engineered paths, and the network becomes more well-behaved and predictable, according to Nortel.

Although Nortel; BT, a pioneer in IP networking; and now World Wide Packets are all behind PBT, this new technology is still very early in the standards process. But while the IEEE 802 study group has just recently begun looking at PBT, Hawkins says the technology won’t require much change beyond what is already adopted for 802.1ah (Mac-in-Mac or PBB).

PBT also faces a potential rival technology known as T-MPLS (the T stands for transport). The idea here is to simplify MPLS from an OAM&P standpoint, said Mike O’Malley, group manager of portfolio marketing at Tellabs, which along with Alcatel was among the companies that initiated work on T-MPLS within the ITU back in May 2005.

Although T-MPLS has made strides on the standards front at the behest of several important vendors, no service providers have yet publicly endorsed T-MPLS.

But some in the industry say there’s no need for either PBT or T-MPLS. Atrica Inc. and Juniper Networks said MPLS and carrier Ethernet solutions available and in use today more than adequately address the requirements of transport networks, and, while PBT and T-MPLS are still in their formative stages, MPLS is already a mature and deployed technology.

According to Juniper Fellow Kireeti Kompella, T-MPLS is positioned as a way to make MPLS more palatable to telcos, who are more comfortable with connection-oriented networking. “Just speaking with an IP-centric language scares a lot of people,” he said.

But MPLS can be connection-oriented, using RSVP, or it can be connectionless, via LDP, Kompella added. The funny thing about the effort to make MPLS more connection-oriented, he continued, is that most service providers using MPLS in their networks are using LDP, so this T-MPLS effort “goes against the grain of what people are actually doing in their networks.”

Saying he doesn’t see T-MPLS gaining any traction in the marketplace, Kompella concluded that “T-MPLS offers nothing significantly different than MPLS except they’ve made a few annoying, subtle changes.”

As for PBT, Kompella said this effort by Nortel to make Ethernet more carrier class by going from a more connectionless to a more connection-oriented construct is also problematic because there are no features in PBT that aren’t already in MPLS. And, he added, PBT requires a whole new control plane and data plane, plus it doesn’t include the fast reroute function found in MPLS. “PBT is what MPLS did 10 years ago,” Kompella said. “PBT is trying to redo all kinds of standards like pseudowire, Layer 2 and 3 VPNs, etc. The point is PBT is now where MPLS was 10 years ago.”

Umesh Kukreja, director of marketing at Atrica Inc., said of the two technologies, Atrica is more aligned with T-MLS, simply because it’s more standard and a better match with what the company already has, but he said both T-MPLS and PBT are essentially doing what Layer 2 MPLS has already defined in terms of traffic engineering and other aspects. He added that both PBT and T-MPLS have been, to date, positioned and discussed for point-to-point services only.

Alcatel www.alcatel.com  

Atrica Inc. www.atrica.com  

BT www.bt.com  

Juniper Networks www.juniper.net  

Nortel www.nortel.com  

Tellabs www.tellabs.com  

World Wide Packets www.worldwidepackets.com

Share this article: Email, Slashdot, Digg, Del.icio.us, Yahoo!MyWeb, Windows Live Favorites, Furl
Add this article feed to: RSS, My Yahoo, Newsgator, Bloglines