HPCwire: Optical Cables Light Up InfiniBand

The Leading Source for Global News and Information Covering the Ecosystem of High Productivity Computing

HPCwire >> Features

August 17, 2007

Optical Cables Light Up InfiniBand

by Michael Feldman, HPCwire Editor

Page: 1 of 2
1 | 2 All »

As InfiniBand data rates rise and clusters grow in size, copper cable technology is getting stretched to its limits. The current InfiniBand Double Data Rate (DDR) of 20 Gigabits per second (Gbps) means that conventional copper cable is limited to an 8 to 10 meter reach. While this might be fine for moderate sized clusters, as systems expand, the physical layout of the cluster becomes a real challenge.

The problems of copper as an interconnect media are numerous. It's heavy and bulky, making it difficult to physically manage in the datacenter. The bulkiness is a particular problem when it comes to maintaining airflow around the systems to maintain proper cooling. And because of the nature of electrical signals, electromagnetic interference limits copper's performance and reliability. These problems really start to add up when you have hundreds or thousands of connections in a scaled-out high performance cluster.

Fortunately, optical fibers provide a capable alternative to copper for higher data rates and longer distances. The problem has always been cost. The optical fiber itself is less expensive than copper, but the transceivers required to convert the optical stream to electrical signals makes these solutions prohibitively expensive at shorter distances. That's why optical is the solution of choice for long-haul networks. At the level of the computer this model is inverted. The highest data rates are on the processor, which represent the shortest communications distances. As you move away from the CPU, onto the board, the backplane, and then out of the box, distance increases and data rates drop. To get optical connections at the volumes required for computer systems, low-cost solutions will be necessary.

That process has begun. Two companies, Intel and Luxtera, have recently unveiled optical cable products aimed at HPC clusters that are using the higher data rates of InfiniBand. The cables will also support 10GbE traffic, but until 40GbE gets established, InfiniBand will be the principle driver for these products. Intel unveiled its optical cables ("Intel Connects Cables") at the International Supercomputing Conference in June. Luxtera announced its "Blazar" optical offering earlier this week.

Intel Outside

While Intel is mainly known for its microprocessors, the company became aware several years ago that copper-based communication was going to become an issue as CPU performance outpaced communication bandwidth at all levels of the system. The company's silicon photonics research effort is one instance of their desire to move beyond traditional electrical interconnects. While a complete silicon photonics solution is probably years away, Intel's optical cables are a commercial product today and represent the company's answer to the copper problem for cluster interconnects.

Intel's optical cable offering is aimed squarely at the rapidly expanding HPC cluster computing market, which has the most pressing need for high bandwidth, low latency communication. The cables support SDR and DDR InfiniBand (and 10GbE ) and boasts bit error rates (BER) of at least 10^-15, 1000 times better than top-of-the-line copper. Due to the nature of the optical fiber, they are 84 percent lighter than their copper counterparts, take up 83 percent less space and have a 40 percent better bend radius. The cable assemblies can be built in lengths ranging from 1 to 100 meters, enabling a lot more flexibility in system layout -- even allowing for configurations that extend into multiple rooms and multiple floors.

Tom Willis, general manager of Intel Connects Cables, thinks if people are going to build large (1000-plus node) clusters using InfiniBand, they're going to need this product. He says their business model is based on the assumption that all clusters requiring DDR interconnects of 10 meters and above would go optical, while 10 meters and below would stay as copper. But Willis says they're actually seeing some orders for sub-10-meter cable assemblies, where people are interested in the better BER and easier manageability of optical.

The product is currently in production release, but deliveries won't be take place until the end of the year. "This is just the first product," notes Willis. "Over time, all the high performance links out of your computer are going to be optical."

Luxtera Raises the Stakes

Page: 1 of 2
1 | 2 All »

Article Tools

Share Options

(Digg, Technorati, more)

Subscribe

Subscribe to HPCwire

Discussion

There are 0 discussion items posted.

Join the Discussion

You must be a registered user in order to comment on HPCwire stories.

Members enjoy:

	Access to Special Content, including Podcasts, Webcasts, and Whitepapers and more!
	Ability to take an active role in the discussions that are shaping the HPC technology discipline!
	Special offers available only to HPCwire members!

Become a Registered User Today!

Registered Users Log in Here to Comment

Email Address:	Password (case sensitive)

Remember me	Forgot Password?

RSS Feeds

Feeds by Topic

Feeds by Industry

Feeds by Content Type

Top Headlines

Intel Partners See 'Easy' Upgrade Path With Xeon 5600 Chips

Mar 18 | ChannelWeb | Westmere parts already showing up in HPC machines. Read more...

AMD: OEMs primed for Opteron 6100s

Mar 17 | The Register | But what about the tier ones? Read more...

Arrival of the Desktop Supercomputer

Mar 17 | Cadalyst Magazine | A new generation of workstations is changing the nature of technical computing. Read more...

Scheduling HPC In The Cloud

Mar 17 | Linux Magazine | Latest iteration of Sun Grid Engine able to tap into Cloud. Read more...

Tailoring Medicine with Supercomputers

Mar 16 | Bio-IT World | Biotech firm builds genetic models from patient data. Read more...

Read more headlines...

Featured Whitepapers

Virtualization for Aggregation And The vSMP Architecture™

Jan 12 | | In-depth look at vSMP Foundation server virtualization technology, technical implementation, use cases and capabilities. The technical whitepaper provides an architectural overview and details on the three vSMP Foundation products: vSMP Foundation for SMP, vSMP Foundation for Cluster and vSMP Foundation for Cloud.

Copper Cable Technologies for High Performance Computing

Jan 18 | | This white paper discusses Gore’s copper cable assemblies, and how they continue to exceed the standards for providing reliable, cost-effective solutions for high-performance computer applications.

View the White Paper Library

Multimedia

Webcast: Virtualized Data Center Roundtable

Join this online panel discussion for live Q&A with leading industry experts, analysts, and end-users to discuss the latest innovations, best practices, barriers to implementation, and measurable benefits of server virtualization with a particular focus on today's real world solutions.

Webcast: Watch SC09 Birds of a Feather Video: Scalable Fault-Tolerant HPC Supercomputers

Learn about scalable fault-tolerant architectures and examples of energy efficient and scalable supercomputing clusters using dual QDR InfiniBand to combine capacity computing with network failover capabilities with the help of programming languages such as MPI and a robust Linux cluster management package.

Webcast: High Performance Computing for a Smarter Planet

LIVE@SCO9: The IBM team discusses new innovations in hardware, software and services that help clients better understand their workloads and get insight from their R&D efforts. Technology demonstrations include the soon-to-be-released Power7 HPC processor, the DCS990 system with 2.4 petabytes of storage, the xCAT management tool, secure HPC cloud computing and more. Winners of two HPCwire Readers' and Editors’ Choice Awards! Take the IBM virtual tour at SC09 or more information go online to: http://www-03.ibm.com/systems/deepcomputing/sc09.html