A Guide to PBT/PBB-TE
Provider Backbone Transport (PBT) is a new, rapidly evolving, and highly controversial development in Ethernet technology. But for all its controversy, the technology has the potential to revolutionize the construction of carrier access and metro transport networks.
It promises to combine traditional Sonet/SDH-like connection capabilities and operational features with the lower costs and packet-oriented advantages of carrier-grade Ethernet. That gets loads of attention because PBT represents a huge break with the long-established orthodoxy that sees Multiprotocol Label Switching (MPLS) technology playing the central role of providing transport connections in carrier packet-based networks. (See MPLS in Access Networks.)
Add to this that PBT is only just beginning to become a commercial product, that standardization is still ongoing, that there is limited evidence of the real benefits to carriers, and that vendors in the PBT space are not all singing from the same hymn sheet. Given all that conflict, we found it hard to resist publishing this guide to the key issues and views on the technology, as a follow-up to last year’s initial report "PBT: New Kid on the Metro Block." Additionally, this guide is supplemented by a survey of vendor and component maker views, a second report called "PBT/PBB-TE Guide: Vendor Talk." What's in a name?
Although some use it as a generic term, PBT (Provider Backbone Transport) is strictly an informal moniker introduced by Nortel Networks Ltd. and BT Group plc (NYSE: BT; London: BTA) for this relatively new flavor of carrier-class, connection-oriented Ethernet that has recently ruffled a lot of feathers in the industry.
PBB-TE (Provider Backbone Bridge – Traffic Engineering), on the other hand, is an ongoing standardization and extension of the basic PBT idea, but it is still some time away from producing the first products based on that technology standard. Since the first (PBT) is technically a proprietary network solution and includes things that the other (PBB-TE) doesn’t, while PBB-TE technically doesn’t yet exist, and will include things (some as yet unknown) that PBT doesn’t, it’s difficult to come up with a simple generic term to cover both.
"We regard PBT as an informal and more general term," says John Hawkins, senior marketing manager for carrier Ethernet at Nortel. "It simply rolls off the tongue more easily than PBB-TE."
Whatever you call it, carrier interest in PBT and PBB-TE is growing, and companies that have committed to using the technology in their networks include BT (in the U.K. and in Italy, where it is up and running), CNC, Dakota Carrier Network LLC , Frontier (an ILEC that's part of Citizens Communications Co. (NYSE: CZN)), groupe-e (a Swiss utility), Highland Telephone Cooperative, Mumbai International Airport, Promigas Telecomunicaciones (Colombia), Silk telecom , and Southern Light.
Another batch, which includes BCE Inc. (Bell Canada) (NYSE/Toronto: BCE), Deutsche Telekom AG (NYSE: DT), Orange (NYSE: FTE), NTT Group (NYSE: NTT), Swisscom AG (NYSE: SCM), Telefónica SA (NYSE: TEF), Telia Company , and Verizon Communications Inc. (NYSE: VZ), is either trialing the technology or rumored to be looking at it closely.
Underlining this interest was the big carrier Ethernet interoperability test run by European Advanced Networking Test Center AG (EANTC) at the Carrier Ethernet World Congress in Geneva in September 2007. Nine of the 24 vendors involved participated in a PBT network, compared to four with T-MPLS, the MPLS-derived analogue to PBT/PBB-TE.
“To have that many vendors with working implementations – it was evident that PBT had a serious momentum behind it, and was a real technology that people were considering,” says Mike Haugh, Ixia (Nasdaq: XXIA)'s senior product line manager. (Ixia provided some test equipment for the event.) He added that major service providers in the U.S. and Europe are asking vendors for some sort of PBB-TE support within "a year or two years."
"We really see PBT as a shift in the market," says Peter Lunk, director of service provider marketing for Extreme Networks. "The MPLS market has been winnowed down to a couple of big players, and I think that this is really a chance for other vendors to move back in and say: 'Hey, the metro piece and the edge of the network really ought to be built out using a lower-cost technology.'"
But, as Light Reading has widely reported (for example: AlcaLu's Alwan: PBT Will Lose Its Shine , 2007 Top Ten: Technologies to Watch, PBT Cost Claims Questioned, and BT Counters PBT Claims), PBT/PBB-TE remains controversial. This report aims to look at the problems PBT/PBB-TE addresses, make a tally of where different vendors stand, and indicate some of the things they are doing to develop and implement the technology. Like Gaul, our consideration of this topic is divided roughly into three big parts. First, there is a very quick rundown on what PBT/PBB-TE is, followed by an overview of why the technology has generated so much fuss, and how it relates to other technologies and carrier needs.
The report then moves onto more dangerous ground by looking at some vendor attitudes to the technology, its development, and its leading MPLS alternatives. It is no secret that the industry is going through one of its periodic philosophical (soon to be commercial) squabbles over PBT/PBB-TE versus MPLS. It is curious how an industry ultimately based mostly on optics manages to generate so much heat and so little light on such issues.
The third part of this editorial effort required a completely separate report: PBT/PBB-TE Guide: Vendor Talk. That report presents a summarized survey of some of the vendors either in, or near to, the PBT/PBB-TE market, giving more detailed information on their views on the technology, its role and applications, their approach to the market, and its possible development.
Here’s a hyperlinked list of this report's contents:
- Page 2: PBT/PBB-TE Recap
- Page 3: Why PBT/PBB-TE?
- Page 4: PBT/PBB-TE Selling Points
- Page 5: MPLS & PBT/PBB-TE
- Page 6: Early Application Drivers & Experiences
- Page 7: Philosophical Warfare
- Page 8: Technology Challenges, Part I
- Page 9: Technology Challenges, Part II
- Page 10: PBT/PBB-TE Future
— Tim Hills is a freelance telecom writer and journalist. He's a regular author of Light Reading reports.
Next Page: PBT/PBB-TE Recap