Electronic Design

Fast, Quick, Speedy... It's All A Comm Game

Higher data rates remain the holy grail of communications and networking, with lower power consumption running just behind as a revered prize. And, what we're seeing in the chase for more performance using less power is the prominent role played by Ethernet.

10GE On The Move
Even though it's been available for years, 10-Gigabit Ethernet (10GE) is finally rolling out. Less expensive optical transceivers and other components are making the transition more affordable. Also, more Internet traffic is pressuring data centers and IT departments to upgrade.

Recent studies conducted by TheInfoPro show that 26% of enterprises interviewed have adopted 10GE in their core networks, a figure that's set to grow to over 30% by year's end. Another research group, CIR, projects the market for 10-Gbit/s optical modules to surpass $4.2 billion by 2011. Most of that growth is expected in the 10GE Ethernet transceiver sector, with the remainder coming from modules for OC-192 Sonet and 10Gbit/s Fibre Channel.

Though optical versions of 10GE dominate the market, companies like KeyEye Communications and Solarflare have been working on a twisted-pair version of 10GE. Known by the IEEE standard designation 802.3an or 10GBaseT, this version of 10GE is based on the use of CAT6a twisted-pair cable and standard RJ-45 connectors. That speed is difficult to obtain over copper cables, but the standard calls for such throughput at a range up to 100m, which is the usual distance for other Ethernet standards.

Chuck Fox, CEO of KeyEye, expects his company to have a single-chip 10GBaseT chip later this year. It will be optimized for shorter-reach applications (less than 30 m), which actually account for about 80% of all cable needs in most data centers. Once such chips are available, the price of 10GE will plummet from about $1000/port for optical Ethernet to less than $100/port, further accelerating its use in networks.

Solarflare, another 10GBaseT chip maker, has demonstrated products over 100 m or CAT6a cable in Systimax Solutions structured cabling systems. The company expects to have a final product later this year as well. Startup Vativ Technologies also has a non-standard solution that uses Cat5e and plain Cat6 to achieve 10 Gbit/s up to 30 m.

Meanwhile, other 10GE efforts like the iWARP system from NetEffect enable companies to make practical use of that fast blast of data. The Ethernet iWARP is the Internet Engineering Task Force (IETF) standard that exploits existing data-center architecture to boost 10GE performance, which is hamstrung more by CPU limitations and inherent latency than data rate. Such refinements are making Ethernet the medium of choice for local-area networks (LANs), as well as metropolitan-area networks (MANs).

That movement continues with efforts to create a "carrier-grade" Ethernet with standardized services, scalability, reliability, quality of service, and service-management features. This version of Ethernet will be able to compete with, and perhaps eventually rule over, ATM and frame relay in the wide-area-network (WAN) space.

It's Time For 100 Gbits/s
The IEEE's 802.3 Higher Speed Study Group (HSSG) is looking at ways to jump to 100 Gbits/s. For some time, this group and others have considered 40 Gbits/s as the next node. Why? Because numerous companies making OC768 SONET equipment for 39.812 Gbits/s already have achieved this performance.

The preliminary goal is to support reaches of at least 100 m on OM3 multimode fiber (MMF) and at least 10 km on single-mode fiber (SMF). One possibility is to use 10 10-Gbit/s streams using 10 wavelengths (l) in a dense wavelength-division multiplexing (DWDM) system. For shorter distances, as in LANs, multiple fiber solutions are possible.

A single 100-Gbit/s bit stream doesn't seem possible, as the silicon to generate and receive it isn't there yet, nor are processors and memories to handle that blitz of data. A standard draft isn't expected until 2010 or later.

Though still a few years off, 100GE should show up just in time to facilitate the implementation and growth of Internet2 (a consortium of research organizations, government agencies, and universities who have built a separate, faster Internet backbone to develop and test new and faster networking technologies and to support their research work), as well as the massive growth in Internet data. Such a boom will be triggered by Internet Protocol TV (IPTV) and other forms of video (see "IPTV Gets Ready For Prime Time").

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