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Cat 6 Turns One

In the past 12 months, there have been a number of positive developments in the industry that support the use of better performing cabling.For this month's column I wanted to step back and take a look...


June 1, 2003  


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In the past 12 months, there have been a number of positive developments in the industry that support the use of better performing cabling.

For this month’s column I wanted to step back and take a look at where we are in the cabling standards development process in relation to the applications, emerging technologies and market trends.

It was about this time last year that the TIA standard for Category 6 was first published. The key difference between Category 6 and Category 5e cabling is in the transmission performance.

At the time, many end-users were asking questions about what applications could take advantage of this improved performance and whether the benefits of Category 6 could be justified in the long run to offset the higher initial investment.

Since then there have been a number of positive developments in the industry that support the use of better performing cabling.

PREMIUM DROP

The first is relative economics. In general, cabling pricing has declined in the last year. More significantly, the premium for Category 6 is much less than it was last year. The tendency today is for about 50 per cent of new installations to specify Category 6 performance or better.

The second is the emerging application for 10 GBASE-T, which is currently under study in the IEEE 802.3 working group. This ad-hoc study group is considering both Category 6 and installed base Category 5e cabling.

However, as the group investigates different cabling models and transmission schemes, it is becoming evident that better performance is required than currently specified, for frequencies as high as 625 MHz.

DEMANDING APPLICATIONS

The third positive development is that Category 6 cabling provides advantages for the most demanding applications on the market today. These include broadband video and IP Telephony, for different reasons. Let’s look at these applications separately, starting with IP telephony.

To successfully implement IP telephony requires a network with a high Quality of Service (QOS). How does cabling affect the QOS? Isn’t Category 5e good enough for Fast Ethernet (100BASE-T)? I thought so, until I listened to a consultant tell me that from his experience with IP telephony installations, additional headroom beyond Category 5e was required to assure a satisfactory QOS.

Although IP telephony doesn’t need much bandwidth, it is sensitive to errors on the network.

These errors have much more effect on a voice signal than on a data signal, since voice is real time, and a lost frame is immediately apparent in the quality of speech.

In the case of data transmission, bit errors can result in retransmissions and some additional delay, which is not that apparent for most applications.

Studies performed in the TIA power separation task group indicate that Category 6 has twice the noise immunity from external interference compared to Category 5e. Better cabling can alleviate problems due to equipment variations or excessive noise in the environment.

Finally, broadband video or CATV is one of the most demanding applications on the market today. It is principally used for home entertainment and for audio-visual installations in theaters, exhibitions, retail stores, educational facilities and hospitals.

It is possible to implement a converged network in which video, voice and data share the same IP circuit, but there are many QOS issues to deal with such as traffic congestion and bandwidth management. It makes sense to have a separate network for broadband video.

One way to do this is to install coax, although it would be prohibitive to do so to every location just in case it is needed. A better way is to make use of the broadband video capability inherent in Category 6 cabling and beyond.

The applications for video include “video on demand” from a video server, monitoring of security cameras, video conferencing and specialty channels for Satellite or CATV broadcasts.

All these applications can be controlled using the IP data network.

I wanted to summarize some of the positive developments that are supporting the migration of your network towards better performing cabling. These developments include more attractive economics in the marketplace, a higher quality of service and support for more demanding applications such as broadband video and the potential for 10 Gig Ethernet over copper in the future.

Paul Kish is Director, IBDN Systems & Standards at NORDX/CDT. He is also vice-chair of the TR-42 engineering committee.

Disclaimer: The information presented is the author’s view and is not official TIA correspondence.


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