EENY: Backhaul Debate

10:35 AM -- NEW YORK -- Ethernet Expo Americas 2009 -- Is the issue of timing and synchronization the biggest problem facing mobile backhaul?

Some vendors at Ethernet Expo said "no," and I'm not sure I buy that.

That's partly semantics. No one is denying that clock synchronization is necessary and that the standards could be ironed out a bit. (And I should point out that this was a Q&A debate session engineered for controversy, so maybe some vendors were just playing along.) But I'm inclined to think it really is the biggest issue in backhaul.

One reason for the "no" answers seems to be that the all-packet world hasn't gotten here yet, making the fine details of packet networking a bit less urgent. Greg Gum of ANDA Networks Inc. pointed out that 2G and 3G networks remain in operation, and you can get the clock signal from them.

Fair enough, but operators are clinging to TDM backhaul partly out of fear that the packet network will be inadequate -- a fear fed by timing/sync issues. Heavy Reading analyst Patrick Donegan noted in a later session that BT Group plc (NYSE: BT; London: BTA) has packetized its backhaul but still keeps an E1 at each site. "They don't have full confidence" in packet-based synchronization, he said.

It seems more accurate to say those older networks stay up because the packet network isn't ready -- partly because of the timing issue.

You've also got the fact that the industry still hasn't decided how Long Term Evolution (LTE) will handle voice, which means operators have to keep 2G/3G around even as LTE rolls out. But that situation won't last forever, and it doesn't change the need for timing answers.

Round Two: Hossam Salib, vice president of marketing for Positron Fiber Systems , said that a bigger problem is the availability of Ethernet. Really? There are ways of getting around that, with microwave and copper. (And guess what: Positron, which bought Aktino, can serve the latter; see Positron & Aktino Target Access.)

I can afford to be cocky here, because the only service provider on the panel took my side. Clock synchronization is "definitely a challenge. It's something that has to be at the forefront" of equipment design, said Jay Clark, carrier product manager for Cox Business, an arm of Cox Communications Inc.

Here's part of what I mean in describing timing and synchronization as a "problem." It's not that the technologies involved, Institute of Electrical and Electronics Engineers Inc. (IEEE) 1588 version 2 or Synchronous Ethernet (SyncE), are bad. They're just unsettled. SyncE gets some sideways glares because every network element has to include it. And Donegan noted that some mobile operators won't put 1588 in their networks "because they can break it in their labs left, right, and center."

And there's a human element: Mobile operators are new to Ethernet transport, making something like 1588 or SyncE a bit of a mystery. "You go to any of these major organizations -- Orange France (Paris: OGE), Vodafone Group plc (NYSE: VOD), or the others. How many people do they have in their organization who know what the hell it is?" asked Sten Nordell, CTO of Transmode Systems AB . "You have to wait some time until the operators understand," possibly two to five years, he contends.

I don't doubt that the mobile network is moving entirely to packets, and that can't happen until the timing and synchronization answers all get nailed down. It's like having a nearly flat tire on your car. You can drive that way. But you'd be best advised to fix it right away. I'd make it a top priority.

— Craig Matsumoto, West Coast Editor, Light Reading