EPON Evangelists Talk 10-Gig
Pushing back against the publicity GPON has been getting, the EPON camp may be revving up for a jump to 10 Gbit/s.
The possibility of a 10-Gbit/s EPON standard is being proposed to the Institute of Electrical and Electronics Engineers Inc. (IEEE) , according to Rex Naden, CEO of EPON chip vendor Teknovus Inc. EPON in its current form was weaved into the IEEE 802.3ah standard for Ethernet in the First Mile. (See Ethernet in Access Networks.) "The IEEE will be voting at the meeting on a study group for 10-Gbit/s EPON. There are very large companies that have lined up in support of that activity," Naden says.
Of those large companies, only Japanese carrier KDDI Corp. has stepped up publicly. Earlier this week, KDDI and Teknovus jointly announced the existence of a roadmap for next-generation EPON but KDDI hasn't guaranteed it will use equipment containing Teknovus chips, Naden says. (See Teknovus, KDDI Tout EPON.)
Teknovus hinted about 10-Gbit/s EPON since last summer, when fellow EPON chip vendor Passave Inc. announced plans to work with GPON. Teknovus is eschewing GPON, instead choosing to work on this next-gen EPON. (See Chips Draw PON Plans.)
A 10-Gbit/s standard would give EPON fuel against GPON, which has gained attention as vendors chase a GPON request for proposals (RFP) issued by the U.S. RBOCs. (See GPON RFP Weighs In, Nortel: Joining the GPON Race?, and Fujitsu Preps GPON Plans.) EPON reaches speeds of 1.25 Gbit/s upstream and downstream, whereas GPON is standardized at 2.5 Gbit/s downstream and 1.2 Gbit/s upstream. BPON, by contrast, allows for about 622 Mbit/s downstream and 155 Mbit/s up.
The natural target for faster EPON is Asia -- particularly Japan, where EPON has taken hold. Sources last year were saying Japanese carriers were mulling a switch to GPON, but analyst Michael Howard of Infonetics Research Inc. thinks a faster EPON -- including a possible 2.5 Gbit/s speed grade he's heard mentioned -- might short-circuit that talk. "Japan will think about GPON, but as the [faster EPON grades] come up, it might be too natural a step," he says.
Teknovus happens to be the first chip vendor vowing to develop something like NGEPON, and Naden admits the startup would like to propose some technologies for the standard, should the IEEE effort fly. But he says he has no illusions about Teknovus's place next to the larger companies in the EPON world.
"You're working with the giants of the industry, and they certainly have their own ideas. I'm not going to tell you we're going to pre-empt these people who have been working on Ethernet all their lives," Naden says.
Still, Teknovus appears to be making a leadership bid. The company has joined The Ethernet Alliance , the recently launched marketing group that hopes to incubate new Ethernet ideas that strive for standardization. The NGEPON press release quotes an Ethernet Alliance official suggesting Teknovus might use that process to nurture 10-Gbit/s EPON. Other vendors are interested in a jump to 10 Gbit/s but haven't gotten the full skinny on the proposal Teknovus is discussing. "We're aware of it, and yes, we have some interest," says Didier Boivin, vice president of marketing for Centillium Communications Inc. But he added he didn't know just which parties plan to champion the possible IEEE study group.
One source suggests Asian carriers are putting their weight behind the effort, because they don't want to be cornered into using GPON for a speed upgrade, even though GPON can accommodate Ethernet traffic. "If you change to GPON, you trash a lot of things. You start from scratch, to some extent," the source says.
Any speed lead EPON gains might not last long, as a 10-Gbit/s GPON is feasible, according to David Foote, chief technology officer for Hitachi Telecom (USA) Inc. , a vendor that offers both EPON and GPON. Another possibility is to place 10-Gbit/s Sonet directly onto a PON, taking advantage of the parts already developed for OC192. "There's an issue that's going to be going on for a lot of vendors and for the standards bodies. What's going to be the best framing technology for 10-Gbit/s PON?" Foote says. (See Hitachi Intros GPON .)
A 10-Gbit/s EPON could face resistance from the "large community of people that believes GPON is better than EPON," Foote adds. "There are tradeoffs between these two, and those same tradeoffs apply at 10-Gbit/s."
That debate will have quite some time to brew. The technology to build a 10-Gbit/s PON is available, but carriers would be unlikely to start deploying such networks without IEEE standards in place. The associated costs are too high anyway, as carriers need an inexpensive optical networking unit (ONU) to sit at the customer premises, Centillium's Boivin says.
"You can build this kind of PON today. Would it be something you could deploy in mass quantities? I think it'll take a while to get to that point," Naden says.
— Craig Matsumoto, Senior Editor, Light Reading