Latent challenge

As speeds increase the choice facing technologists at financial institutions about whether to specify
copper or fibre cabling systems to meet their capacity, continuity, latency and green challenges is
becoming increasingly complex. Philip Hunter examines the options

The traditional view of structured cabling systems as a low level part of the IT infrastructure, to be installed like the foundations of a building and then forgotten, is passing. This is especially true in the financial services sector, where a variety of factors such as the credit crunch, compliance issues, increasing ‘green’ environmental concerns and the growth in algorithmic trading, are all conspiring to lead cabling to be incorporated within overall systems management. In any case the rapid pace of change in financial IT means that structured cabling systems tend to be upgraded or replaced more frequently than in other sectors, making them more visible within the IT firmament.

Structured cabling is no longer confined to specialists therefore, as it is increasingly incorporated into overall IT management and decision-making processes. “Large structured cabling projects now involve skill sets beyond most traditional cabling engineers and will typically involve networking engineers, Voice over IP (VoIP) specialists and others, so selecting a vendor with these skills in-house will ease any network roll out,” claims Rajesh Sinha, technical director of Bailey Teswaine, a UK Information & Communications Technology (ICT) vendor.

Another trend is a recognition that as reliance on IT systems performing within tight performance margins increases, critical applications can be brought down by failures in physical cable links just as much as in servers, routers and other higher level system components. “Most mission critical environments will have ‘live’ and ‘standby’ servers to counter the risk of hardware failure,” notes Sinha. “The same principle now applies with cabling - ensuring that there are redundant (back up) links with diverse paths further reduces risks of cabling related outages.” Wholesale bank running algo trading applications, in particular, cannot
afford downtime.

If cabling systems are now equal partners alongside servers and routers within IT management, it makes sense also to treat them the same from a purchasing and support perspective, according to Carrie Higbie, global director of data centre solutions and services at cabling specialists, Siemon. “We are seeing a trend towards internal global specifications within major institutions,” she says. “While this has been the case for years with switches, routers and in some cases servers, cabling has been left out. Being able to work with a global manufacturer with an audited warranty and well trained installers removes many of the concerns and wasted dollars that are apparent when just anyone can do the installation, with just any product.”

Latency challenge
The screws are being tightened on the IT infrastructure at financial institutions by the ever-increasing demands for high bandwidth and, in particular, consistent low latency. The proliferation of algorithmic trading and instant settlement engines requires round trip times to be kept within milliseconds, with little room for variation. While the primary cause of latency is simply the length of the path taken by the relevant data, there are other major contributors, notably active components within the cabling system, along with switches and routers, all of which hold data up during signal regeneration, or higher level packet processing. It therefore pays
to keep distances as short as possible on a geographical scale (i.e. avoid having the systems in different continents and utilise proximity hosting solutions where possible), while minimising the number of routers, switches and active components within
the infrastructure.

Remember, although bandwidth is not directly related to latency, if there is not enough of it for an application, data will be held up during queuing, imposing delays. “Providing ‘large pipes’ in the network enables the IT systems to support users who are accessing bandwidth-hungry streaming technologies or who require fast access to information sets, or indeed those who use real-time interactive technologies or market pricing engines,” says Ian Wilkie, business and marketing director at data cabling vendor, Brand-Rex. “Faster speeds will migrate from the core of the network to the edges. It will happen more quickly in early adopter markets and present advantages to them.”

A poorly installed cabling system can also cause latency, this being a problem both for copper and fibre-based systems. In the case of copper, cross talk interference can cause errors so that data packets have to be resent, again causing latency, but this can be more or less eliminated by proper installation. Fibre networks are actually more susceptible to poor installation and subsequent maintenance, since dirt on connectors can cause errors and data retransmission. “Connections must be kept clean if removed and more care and attention is needed when installing and handling fibre,” agrees Wilkie.

Copper v Fibre
The implications of these bandwidth concerns and the latency challenge for cabling systems can be hard to unravel, leading in different directions – either towards copper or fibre – depending upon the existing infrastructure and nature of the applications. The dynamics tend to be different in the financial services sector, with space often at a premium given high densities both of personnel and IT systems, while Return on Investment (RoI) can be quicker given the high-value of wholesale banking transactions and consequent cost of failure. This has been tilting the balance in favour of fibre installations, which will always be ahead of copper in potential capacity, and appears to provide the surest future proofing, also being less bulky than copper. These factors can easily outweigh the extra cost of installation and of the electronic components on trading floors, where space is at a premium and cost less of an issue, even in the current credit crunch.

Yet it is naïve to assume that fibre is totally future proof and will never need replacing. History shows otherwise, since many installations were based on so-called multimode varieties that are limited in range and capacity. Multimode fibre, carrying multiple rays, can admit more light, enabling lower cost electronics than the alternative thinner single mode fibre. But the latter with its greater transmission accuracy can support higher harmonic frequencies and therefore greater bit rates, and is now recommended for structured cabling systems, according to Rosemary McGlashon, European technical manager at 3M Telecommunications, which sells both copper and fibre-based systems. “It is better to use the most ‘future proofed’ cable possible to avoid expensive refits (both in money and energy),” she says. “Looking ahead to future speeds of 40/100Gbit/s, single mode fibre would be the most future proof in my opinion.”

But in fast moving financial trading rooms with their constant overhauls, such future proofing may seem nebulous, and there are still many cases where copper represents the most cost-effective solution anyway, according to Ewan Wilson, managing director of Hellermann Tyton Data, one of the UK’s major cabling product companies. “There have been forecasts of the demise of copper for a long time but I don’t see it happening anytime soon,” he says. “Both copper and fibre have their place in a network and, while the use of fibre has increased as a proportion of the total network as speeds have increased, copper is still an important part of the infrastructure. In my opinion it will remain so for some time to come. The ease-of-use, familiarity and cost of active equipment are still tipping the balance in favour of copper for many parts of a network.”

This indeed is why the 10G BASE-T copper system based on category 6A cable was developed. “The arrival on the market (if not in standards) of 10G BASE-T/Cat 6A systems has widened the choice, particularly ‘to-the-desk’ and in short runs in data centres,” notes 3M’s McGlashon. “This provides financial institution end users with a copper choice, where previously there was only fibre.” Copper is cheaper than the fibre alternative and is being installed to the desktop for quite a few high-speed trading floor applications, although fibre still remains more popular generally for ten gig speeds in the financial services sector.

While arguments about the benefits and constraints of fibre and copper continue to go back and forth, at least the nail finally seems to be in the coffin for thick shielded copper systems, with category 7A being the latest version. Their sheer bulk is a deterrent, while improvement in the quality of unshielded systems has made them more attractive for high bandwidth applications. “CAT7 systems have been largely seen as unwieldy due to the thickness of the cable,” claims Bailey Teswaine’s Sinha.

Green dream
There is one new factor to consider when specifying a new cabling system and that’s the ‘green’ dimension, which is increasingly important given the desire to reduce carbon footprints, and also, with escalating energy costs, cut power consumption. The green factor might seem to favour fibre systems because they consume less power, less plastic in manufacture, and the raw material, silica, is much more abundant than copper (although copper can be recycled). This however ignores the growing interest in
Power over Ethernet (PoE) as a source of electricity for a variety of networking devices. As Sinha notes: “Copper, while becoming more expensive, is increasingly being used to power devices using PoE, so installing structured (copper) cabling can actually
enable greater control of energy consumption and reduce the need for electrical cabling to CCTV points, door access points
and even desks.”

The ‘greenest’ overall solution could well include a mixture of copper and fibre. Even the environmental question therefore fails to settle the debate about which material is better. The one point though on which everyone seems to be able to agree is that while automated management and monitoring of the physical infrastructure is becoming more important, cabling systems themselves are no nearer to becoming commodities, and still require careful installation and upgrading by skilled engineers.

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