10 Gigabit/s Ethernet over twisted-pair copper

Published:2011/8/8 3:26:00 Author:Phyllis From:SeekIC

By Phil Turtle

If we look back over history, there is an observable cycle out of which has grown the dominance of Ethernet — and which causes the ever-present desire of network managers to ’future proof.

Moore’s law states that computing power doubles every 18 months. Although it does not apply directly to active equipment and cabling, it is a significant driver. Active equipment follows a roughly four-year lifecycle. Now here lies the difficulty for network managers. Computers are being changed out every two to four years; actives every four years — yet the cabling infrastructure is expected to last 8, 12 perhaps even 20 years. So it’s quite evident that structured cabling capability has to lead active equipment deployment — in practice, by between four and six years.

Alien forces

There are two technical problems to be overcome in the move from Gigabit to 10 Gigabit/s. One is the much greater insertion loss of twisted pair at 500 MHz, the other is crosstalk — signals induced from adjacent cables that cannot readily be cancelled electronically. Developing a cost-effective, practical 10 Gigabit/s system relies heavily on the passive cabling to counteract these two problems.

So difficult, in fact, is this task that until November 2003 most people in the cabling industry believed that an unshielded (UTP) approach was not possible and that shielded cabling was the only solution. Indeed, many were proposing to exclude even the possibility of an unshielded (UTP) cabling solution from the up-coming 10 Gigabit/s Ethernet standard.

However, an innovative development came from KRONE’S labs who produced a new copper cable - CopperTen’M. After careful measurement and external validation by one of the active electronics manufacturers, KRONE were able to demonstrate to the IEEE study group that 10 Gigabit/s over UTP was indeed a practical proposition.

Shielded or unshielded

From the late 80s there has been disagreement in the industry and around the world as to whether shielded (STP) or unshielded (UTP) cabling solutions are the best, with many companies backing one horse or the other — and then trying to convince the market that theirs is the only way. KRONE has always recognized that both have their advantages in different situations and that whilst STP might be the solution of choice in one market, UTP will be preferred in another. Whilst custom and practice in Germany and central European countries is to use shielded solutions, most of the world is UTP-centric. In fact in 80% of the world the skill base of network designers and installers is in unshielded technology and systems.

This is why KRONE worked against almost impossible odds to prove to the industry that a UTP implementation of 10 Gigabit/s was possible. Otherwise, over the coming years, the industry would have found a situation where every installer would have had to be re-trained and up-skilled to be able to undertake the more complex, and far less forgiving task of installing shielded systems. This in turn would have added three extra cost elements into the 10 Gigabit/s solution - the higher cost of screened cables, the higher labor costs of slower installation and the on-cost of installer retraining. KRONE does not however hold a claim that UTP is the only solution, also developing shielded solutions so that users have choice.

Early adopter risk

As ever, being an early adopter is not without risk. For example, a number of other cable and connector manufacturers have been promoting ’Cot 6e’ products which have focused on improving the internal electrical performance of cables and connectors. As it turns out, these ’improvements’ have proved to be exactly the opposite when it comes to crosstalk — the killer factor for 10 Gigabit/s. Instead, ’augmented Cat 6’, on which the KRONE CopperTen solution is based, is the clear favorite.

The bottom line

10 Gigabit/s Ethernet over twisted pair copper is now certain to become a standard IEE802.3an (10GBASE-T). A structured cabling solution is therefore needed. Generally the structured cabling solution is needed four to six years before the relevant Ethernet ports are installed in bulk.







Network managers need workable solutions as early as possible. Many cannot afford to wait for ratified standards. KRONE’S UTP CopperTen solution offers users the latest technology based on the latest information. With a warranted 18 Gigabit/s Shannon capacity, it outperforms the requirements of all the Ethernet solutions currently being studied. CopperTen is an augmented form of Category 6 UTP technology which installers and managers are familiar with. With its Category 6 pedigree but lOx greater throughput, at a relatively small premium, it could soon become the solution of choice.

Reprinted Url Of This Article: http://www.seekic.com/blog/project_solutions/2011/08/08/10_Gigabit_s_Ethernet_over_twisted_pair_copper.html

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