A quick look behind the racks where users connect back to the servers and the odds are you’ll discover a veritable spaghetti of cables – almost certainly UTP (Unshielded Twisted Pair) copper as specified in the EIA/TIA 568 standard. As demand for throughput continues to rise, however, the data centre is under pressure to deliver not just 10 Mbps but 100 Mbps to the desktop and not just 100 Mbps between servers, but 1 Gbps and beyond.
Although the spaghetti has become slightly less intense with the advent of blade systems in parts of the data centre, the overall cabling challenges – including the bandwidth issues – remain. A big debate is whether fibre is, in the long run, the better investment for the data centre.
Copper cable is large compared with fibre, so space and airflow considerations can become an issue. The thickness of copper can also be unwieldy when it comes to labelling and tidying up copper-based switches: they are far more cumbersome and difficult to see clearly what is going on in comparison to a fibre switch. However, copper cabling is proven, far cheaper and many of the same issues apply to fibre as with copper….
However, copper cabling is proven, far cheaper and many of the same issues apply to fibre as with copper: the quality of the structured cabling installation is paramount. The “structured” part comes with being able to standardise smaller elements of the entire cabling project, governed by a set of standards but with room for manoeuvre and totally screwing up.
Copper to fibre and back again
The subsystems involved are the entrance facilities, where the building meets the outside world; equipment rooms that host kit that serves the users inside the building; telecommunications rooms housing equipment that connects the backbone and horizontal cabling subsystems; backbone cabling: the inter- and intra-building cable connections; horizontal cabling connecting end-user equipment to individual outlets on the floor; work area components that connect end-user equipment to outlets of the horizontal cabling system.
The data centre itself houses the computer systems and associated components, such as telecommunications and storage systems and often includes redundant or back-up power supplies and additional communications links, environmental controls and security devices.
UTP copper – four pairs of insulated, carefully twisted pairs of copper wire – for years meant Category 5e cabling which successfully handles networks up to 1Gbps. Category 6 – meant for more robust data transmission on Fast Ethernet and Gigabit Ethernet, was approved back in June 2002 but stalled as Cat 5e was found to do an adequate job. When 10G Ethernet arrived, it needed fibre and tweaking Cat 6 has proved problematic to date.
With all kinds of backwards compatibility issues, the cost of “rip and replace” compared with upgrading and – rather like finding a builder you can trust – finding the appropriate attitude to go along with the expertise, the challenges of successful structured cabling go far beyond the technical.
