Interview: Dan Blumenthal, Terabit Optical Ethernet Center

Could Terabit Ethernet be the technology that validates optical packet routers?

Craig Matsumoto, Editor-in-Chief, Light Reading

April 22, 2011

7 Min Read
Interview: Dan Blumenthal, Terabit Optical Ethernet Center

In optical networking, 1Tbit/s transmissions is now a serious topic. And Dan Blumenthal, director of the Terabit Optical Ethernet Center (TOEC) says you take a cross section of a data center, you'll reveal petabits per second of data flowing through at any given instant -- so the need for terabit Ethernet isn't that distant. (See The Terabit Ethernet Chase Begins.)

For me, this interview was a great chance to finally meet Blumenthal. I'd spoken with him and his colleague John Bowers, in their capacities as Calient Technologies Inc. founders and University of California, Santa Barbara (UCSB) professors. They were the principal sources in an EE Times article I did circa 2000, about the state of engineering education.

But we'd never met until last month's OFC/NFOEC, where I found Blumenthal was no longer sporting the moustache you see in that EE Times story, but he was still an eager conversationalist. We scrounged some chocolate cake and coffee from an adjourned press luncheon down the hall and found a quiet corner to catch up.


— Craig Matsumoto, West Coast Editor, Light Reading

Light Reading: So I take it you guys aren't done making Terabit Ethernet yet? Where's my Terabit Ethernet?!

Blumenthal: [Swallows a bite of cake.] Just getting the website up and running has been a huge task, with the University of California rules and all.

Light Reading: So the website is harder than Terabit Ethernet.

Blumenthal: [Laughs.]

Light Reading: Are you making much headway recruiting companies to the cause? Standards bodies?

Blumenthal: Companies, yes. Totally the standards bodies. As a matter of fact, John D'Ambrosia [high-speed Ethernet expert, now at Force10 Networks Inc. ] is going to be on -- there are technical subcommittees we have in the center, and standardization is one of them. Verizon Communications Inc. (NYSE: VZ) asked that we have that there; they're one of our founding companies.

John won't chair it, because he's chairing The Ethernet Alliance -- a lot of these guys are way overcommitted -- but he's agreed to come in. He and I really enjoy talking about this stuff. Trying to put together the whole research-to-standardization process, at least to have all these conversations going on early -- he was pretty successful at having that happen with 100Gbit/s.

I've gotten emails from all around the world, from Israel, Japan -- from people I didn't realize were working on terabit optical Ethernet. Then, the Optical Internetworking Forum (OIF) is taking a huge interest in this, so we're forming a tighter bond with OIF.

Light Reading: That's all good, right? You don't have five different Terabit Ethernets starting up.

Blumenthal: It's good to know. I don't think any good idea is going to be one person. You need many people.

If you want a quick history of how things are going right now: We needed to nail down the scope of the center with the founding companies. Now, we're bringing new companies in and meeting with a lot of companies. Then the next layer is institutional affiliation, but we have to be fair. We don't have enough manpower to just affiliate with everybody, right? So we want to choose our affiliations smartly, but it also has to be done with a fair set of rules.

And like I said [to Light Reading in October], this is a grassroots thing, so we're also trying to raise money in real time. It's not like we got some big grant.

Light Reading: So what kinds of companies are coming in? Big? Little?

Blumenthal: We've got big companies that don't want the little companies feeding off of all this. So what value do the little companies bring in? We have to think about that.

Here's the little companies' idea. It was a great idea, by the way. They said: You know, we can go in and compete for the STTRs [U.S. Small Business Technology Transfer grants] or university grants, and if we keep winning base funding, then we can bring in a big company. TOEC can make them very competitive to make those proposals. If they can help bring that funding money in, then that's the small companies' help to the center.

Light Reading: Well, that's good, because the complaint about standards is that big companies tend to railroad things through.

Blumenthal: No one's really had that attitude at all.

Light Reading: I think that's because you starting early. Nobody has anything ready yet.

Blumenthal: And people have a lot of pain right now. I think their jobs are really hard because it's not clear where things are going in terms of the electronics. This pre-competitive ecosystem environment really seems to be palatable for a lot of people.

Page 3: Tech Talk Light Reading: At OFC/NFOEC, I'm suddenly hearing a lot about software-defined optics. Is that something you could use? (See OFC/NFOEC 2011: ADVA CTO Foresees Flexible Optics.)

Blumenthal: We are looking at it in the center. We can call them agile optical transceivers, maybe? I don't know what name you want to give it. But especially as you get to these high symbol spaces for spectral efficiency, you can do much more with the symbol space than spectral efficiency. You can do partitioning, which is something we're looking at but not talking about. I can't go into detail about it.

Light Reading: So if you take 128 QAM, you can assign 56 of them to one guy, the rest to another?

Blumenthal: There are different things you can do. I've heard people talk about -- and certainly this is in our roadmap -- dialing up or down the complexity of the modulation based on the distortion of the channel, or the reach, or whatever. So, maybe if you start hitting degredation that you can't overcome, then you throttle back, kind of like a flow control at the transponder level.

The question is: What does it cost? I hate to say it, but it all comes down to cost, and which part of the application space it's going to be used in.

Another thing -- we're talking about Terabit Optical Ethernet, not about terabit transport. If you have a Terabit Ethernet pipe coming in to a point, are you going to want to break that up with a switch that's going to have a lot of power dissipation? Or, are you going to find a new way to do business with these Terabit Ethernet channels? Optical packet routers may be one solution. Maybe there are others. But I think people are starting to ask very seriously the question: Maybe it's time they can't keep doing business the way they've been doing business.

Light Reading: I hadn't thought about it that way. If you have a terabit, you'll want to keep it a terabit as long as possible.

Blumenthal: If you're a transport guy, you think, "That's not a problem," right? But what happens when you have to interrupt that with something that's not just taking channels off as a drop? What if you're actually doing Ethernet processing? I just don't know how that would fly. But we don't want to rule electronics out. It's always done amazing stuff.

But people are starting to say electronics is finally starting to hit some kind of a wall. They don't know what it is. I don't think anybody wants to be blindsided right now. That's what I'm hearing. So, while they may not rule out electronics always having a solution, it sounds to me like everybody wants to prepare so if that wall happens, they have an alternate route to go down. To me, that sounds like a really good way of doing it.

Following that path, everybody believes photonic integration is one of the key lynchpins. You can't build these things that you're talking about, the programmable, high-constellation systems, without integrated photonics. There's no way. It wouldn't be stable enough.

Back to Introduction

— Craig Matsumoto, West Coast Editor, Light Reading

About the Author(s)

Craig Matsumoto

Editor-in-Chief, Light Reading

Yes, THAT Craig Matsumoto – who used to be at Light Reading from 2002 until 2013 and then went away and did other stuff and now HE'S BACK! As Editor-in-Chief. Go Craig!!

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