Cabling performance and application support

The development in the performance of copper cabling standards has evolved alongside the developments in the increasing amount of data that is required to be transmitted from point A to point B. Sometimes the development of the cabling has led the development of new Ethernet applications and sometimes it has been the other way around.

It is important to be aware of the data transmissions rates that are possible on both existing, legacy cabling and when planning the installation of new cabling infrastructures. The table below summarises the various Categories/Classes of cabling and the applications that can be run over them.

Table of cabling performance and supported applications

Cabling of any given performance will support the application that was designed to run over it as well as any preceding applications, i.e. they are always backwards compatible.

From the above table it can be seen that Cat 5e supports a frequency (bandwidth) of 100 MHz and Cat 6 a frequency of 250 MHz but both will support 1 Gigabit Ethernet. This is because the Cat 6 cabling standard tried to pre-empt the development of a higher speed Ethernet protocol but was, ultimately, found to not be suitable for this purpose. Hence the development of Cat 6A cabling to support the next step change in Ethernet protocols, 10G Base-T. It is, however, true to say that Cat 6 cabling can have other benefits over Cat 5e, including better quality of service for Voice over IP (VoIP) and Power Over Ethernet (POE).

Class F and Class FA cabling were developed in Europe and have no direct TIA equivalent category. This is largely down to the fact that twisted pair cables designed to carry frequencies up to 1000 MHz need to be shielded and the American market has always resisted the use of shielded cables. Despite the fact that these higher classes of cables will still only support 10G Base-T Ethernet they do have some benefits in terms of their ability to support multiple applications on a single cable and even the option to transmit full bandwidth television signals over the twisted pair cabling infrastructure.

When planning a new cabling infrastructure it is important to consider not just what the cabling is required to support now but also what it is likely to support within the lifetime of the network. It is far more cost effective to install a higher performance cabling system on day one than to have to rip out a lower performing, cheaper cabling system and replace it a few years down the line.