If you're about to build a new Ethernet network or upgrade an existing one, be sure to consider installing an infrastructure that will support 10Gbps bandwidth, even if you don't need that much speed right now.

Networks are like race cars in at least one respect: faster is always better. Unlike with race cars, the attainable (and affordable) speeds for networking have increased tenfold every few years. In the 90s, most Ethernet networks were running at 10Mbps. By the turn of the century, the typical speed had increased to 100Mbps. Today, 1Gbps is becoming the norm -- and standards for 10Gbps have already been developed.

If you have plans to cable a new building or replace your existing network infrastructure in the near future, you might want to look ahead and ensure that it will be easy to scale up to meet the need for increased speed as your network traffic grows and applications become even more bandwidth-hungry. In this article, we take a look at emerging 10Gbps technology, how it works, who's going to need it, and what you'll have to do to take advantage of it.

The need for speed
Why would anyone ever need a 10Gbps LAN connection, when many of us get along fine connecting to our local networks with 54Mbps wireless (or less)? There are actually a number of reasons:

• Files keep getting bigger -- and higher speed means faster transfer of those large files.
• Applications, especially real time applications such as streaming video, voice over IP, etc., need plenty of bandwidth to work properly, and the applications of the future are likely to need even more.
• The total network bandwidth is shared, so the more users you have transferring those big files and running those bandwidth-intensive network applications simultaneously, the more bandwidth you need.
• Higher speed switches are needed in datacentres to aggregate the traffic from desktops and servers that are already running at 1Gbps.

A good rule of thumb in IT planning is to estimate the size, speed, etc. that you think you'll need in the future and then multiply that by at least five. Remember that there was a time when no one envisioned a need for computers with megabytes -- let alone gigabytes -- of RAM.

According to a study done by TIP (TheInfoPro) in July 2006, many enterprises are already installing 10Gbps Ethernet either in pilot programs or in their production environments. In fact, about 30 percent of survey participants had already installed it or planned to do so in the near future. The most popular application is for network storage in datacentres.

10Gbps over copper: How it works
Ethernet operates at layers 1 and 2 (physical and data link) of the OSI networking model. It's defined by IEEE 802.3, and the 10Gbps standard is defined under 802.ae. It follows the same standards (MAC protocol, frame sizes and format, etc.) as the original Ethernet standard. The only real difference is that it doesn't use or need the Carrier Sense Multiple Access/Collision Detection (CSMA/CD) protocol common to other Ethernet specifications because it runs only in full duplex.

First, the physical media (cable) must support the high speed. The first implementations of 10Gbps, and the 10GBase-T standards that were ratified by the IEEE in 2002, ran over fibre optic cabling, but fibre is still relatively expensive and difficult to work with. Thus great efforts have been expended to find a way to run 10Gbps over copper cabling. Categories 5e and 6 unshielded twisted pair, pretty standard for Ethernet cabling today, can support 10Gbps at distances of 55 metres (a little over 180 feet). This is compared to the usual 100 metres (approximately 328 feet) for Ethernet. A better alternative, supporting the full 100 metres, is "augmented" Cat 6 or Cat 7 cabling, which reduces the problem of alien crosstalk (ATX), which is electromagnetic interference that occurs when different cables run alongside each other in a bundle (this is in contrast to regular crosstalk, that involves signals on individual wires within the same cable).

Various vendors offer solutions. For example, earlier this year Systimax introduced its GigaSpeed X10D UTP cabling for 10Gbps deployments. It was developed to meet Cisco's criteria for interoperability with their products.

The IEEE standard, however, doesn't just increase the speed but also the operating distance -- up to 40 kilometres over fibre optic cabling. This makes it appropriate for campuses, Metropolitan Area Networks (MANs) and Wide Area Networks (WANs). The distance for single mode fibre in 1Gb Ethernet is only 5 kilometres.

Planning considerations
For several years, the main use of 10Gbps technology was for network backbones, but with 10Gbps Ethernet running over copper wires, it's now feasible to run it all the way to the user desktop.

What about cost? As the current top of the line, 10Gbps is expensive -- but a lot less expensive than it used to be. In early 2003, shortly after 10Gbps standards were defined, the 10Gbps hardware cost almost US$40,000 per port.

Even if your organisation doesn't have the need or the budget to implement 10Gbps now, you can be sure that within a few years it will replace today's gigabit networks just as they have replaced yesterday's 10/100 networks. So it pays to start thinking about 10Gbps now, and as you install new cabling or replace segments of your network cabling, especially in backbone or datacentre areas, to go with an infrastructure that will support the higher speeds when it's time to upgrade.

Summary
Right now, a 10Gbps infrastructure might seem like the ultimate upgrade, but the day will undoubtedly come when we'll look back at it as the old, slow technology. Meanwhile, Ethernet has survived as the networking architecture of choice while others (such as Token Ring and ARCnet) have faded away because its simplicity, flexibility, cost and ease of installation, maintenance and management are superior. 10Gbps Ethernet is the next generation in that long and distinguished line, so get ready for it.

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