Design Con 2015

100-Gbps Ethernet: In demand now

-May 08, 2008

John D’Ambrosia of Force10 Networks is chair of the IEEE P802.3ba Task Force, whose job is to develop a standard for 40-Gbps and 100-Gbps communications links. The 802.3ba designation was approved on December 5, 2007. The IEEE 802.3ba Task Force is responsible for producing a standard in 2010. I spoke to D'Ambrosia by telephone from his office in Harrisburg, PA.

Q: At several sessions at OFCNFOEC 2008, people noted that the existing pipelines for data communications have filled up and that the communications industry needs more bandwidth. What caused that to happen?
A: Online video is a large factor for the increased bandwidth demand. People can download entire TV shows.  YouTube has had a huge impact. Yahoo Asia Pacific streamed Major League Baseball games, but its 40-Gbps video pipeline quickly filled, and as a result the actual demand for capacity was unknown. Video isn’t just an evolution in increased bandwidth demands, it’s a step increase.

There are other bandwidth demands, too. R&D and medical computer files are quite large now. Every time imaging systems with increased resolution appear, they increase file sizes that consume more bandwidth. I’ve even heard of a small construction company that needs 60 Gbps of bandwidth

Q: You spoke at this year’s OFCNFOEC about the need for more bandwidth now. Who has been asking for more bandwidth?
A:
It’s come from many sources. Cable operators such as Comcast and Cox are looking for more bandwidth. Data-center operators such as Google and Facebook have thousands of servers that they need to aggregate into high-speed links. Demand has also come from broadband access providers, due to increased access penetration and rates.  Data centers have indicated they see a need for the service provider community, because telecom companies are having difficulty providing enough 10 Gbps links. Content providers are also looking for more bandwidth.

It goes beyond those who directly need 100 Gbps, too. Companies selling servers to Facebook, which has thousands of servers, never see the need for 100G in their product offering, but the server provider being able to support additional 10G requests will enable them to sell more GigE servers.

Q: Switching to IEEE 802.3ba, please highlight the objectives of the project.
A:
In short, the objectives of the IEEE 802.3ba project are to provide a specification for 40 Gbps and 100-Gbps Ethernet links for transmission over single-mode fiber, multimode fiber, copper cables, and copper backplanes. It will support full-duplex transmission with bit-error rates (BERs) less than or equal to 10-12. Testing to lower than 10-12 needs to be considered carefully as it might impact test time and translate to increased cost. 

Q: What is the current status of IEEE 802.3ba?
A:
Currently, the 802.3ba Task Force is hearing proposals on technical issues. We’re receiving a flood of proposals leading up to a meeting on May 13 through 15 in Munich.

Q: What might happen at the meeting?
A:
We will collect the proposals and distribute them to all Task Force members and begin the review process. Given the size of the project and the number of proposals, I expect the process to continue through the September meeting. A number of people will have a technically intensive summer leading to another meeting in September. Task Force members will debate the merits of each proposal to select those that we’ll incorporate into a draft standard.

Q: How many people are involved?
A:
The task force has over 150 members and there are approximately 800 people who read postings to the 802.3ba e-mail reflector. Other groups such as the Ethernet Alliance, the Optical Internetworking Forum, and the International Telecommunication Union are paying attention to our activity. I expect we’ll have a large gathering in May.

It’s an open process. Anyone can join the debate. Because an IEEE standard needs a 75% vote of Working Group members for ratification, participants in the standards process must build consensus. Companies have different technical solutions to the problem and they have investments in those solutions. Everyone has an agenda.

Q: What do you think will happen September?
A:
My goal is to have all of the technical decisions done. That leaves us to create draft 1.0 of the standard coming out of the September meeting. The draft then goes to the full Task Force for review. We then begin work on a technically complete document. We may have some numbers left at this stage as “TBDs”. The task force then works out those details and presents a complete draft standard to the 802.3 Working Group body to go to the working group ballot stage. That’s currently scheduled for March 2009.

At that point, we open up the document to all members of the 802.3 Working Group, not just the Task Force. After the Working Group ballot is approved, the document goes to the IEEE Standards Association group for comments.

Q: Clearly, the timeline is dependent on the results of each meeting, correct?
A:
We have a timeline, for without one we will never get the job done. If there’s a technology void because a standard is dragging on, then someone will create a solution to the technical problem, but without a standard. People have told me that they need 100-Gbps Ethernet now.

The adoption of a 100-Gbps Ethernet standard, perhaps made up of ten 10-Gbps or four 25-Gbps lanes, will fuel the need for new test equipment. We need to think about how we will test not only transmitters and receivers, but backplanes and cables, too.

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