10GBASE-T Ratified
In July 2006 the IEEE ratified 10GBASE-T. This new Ethernet standard specifies 10Gb/s data transmission over up to 100 metres of four-pair copper cabling. Publication of the standard will allow manufacturers to press ahead with the launch of new network equipment and NIC cards with 10GBASE-T interfaces.
Cat6
Although 10GBASE-T will not run over Cat5e it will in the right circumstances run over Cat6/Class E UTP cabling. However, because the transmission requirements in the 10GBASE-T standard exceed those specified for Cat6/Class E, 10GBASE-T will only achieve limited distances over Cat6/Class E UTP. Cabling standards bodies will be publishing informitive documents for the installed base of Cat6/Class E cabling that are intended to provide guidelines to verify support for 10GBASE-T. These guidelines will include a number of mitigation procedures that range from unbundling of cables to replacement of various components in order to minimise crosstalk from adjacent channels. A maximum distance of 37 metres may be achievable in some cases but this may require following some of the mitigation steps.
Cat6A/CLASS EA
In anticipation of the Cat6 limitation with 10GBASE-T, cabling standards boodies have been developing new Cat6A/CLASS EA specifications that will guarantee 100 metre support over 4 connections for new installations.
As well as requiring stable performance of the traditional parameters (such as NEXT) up to 500MHz, the new standards have also introduced new paramaters not characterized in the past, including alien crosstalk (PSANEXT and PSAELFEXT), which measures the effect of one channel on adjacent channels.
In a break from tradition (Cat6 and CLASS E are effectively equivalent), the draft CLASS EA standard is slightly more demanding than the draft Cat6A. A 10G cabling system should therefore ideally be specified to meet CLASS EA, thereby also providing the guarantee of meeting Cat6A.
The Cat6A and CLASS EA specifications are likely to be ratified late 2006/early 2007. Meanwhile, the draft specifications are mature and unlikley to undergo significant change before publication.
Choosing a 10G Copper Cabling System
Over the past two years, most major cabling manufacturers have launched new '10G ready' cabling systems. Admid the inevitable confusion relating to evolving standards, these have been accompanied with varying technical claims and specifications of what standards these systems will meet and in what circumstances.
It is now clear that when selecting a 10G 'Cat 6' cabling system, whether UTP or STP/FTP, the main requirement is that the complete channel (not just the cable) should meet the (draft) Cat6A/CLASS EA specifications. Meeting of this requirement will not only guarantee meeting of the 10GBASE-T requirements over 100 meters/4-connectors, but will also ensure that the cabling can support other standards that will be deveoped for Cat6A/CLASS EA in the future.
Another consideration when selecting a 10G cable system is its physical construction. For most purposes Cat5/Cat5e and Cat6 systems are physically the same. However, whilst reducing the alien cross talk on UTP systems, manufacturers have designed a range of interesting cable and patch panel designs. Cables can be quite bulky compared with Cat6, some also coming with various twists and non-round shapes. Patch leads are also typically less flexible.