Products may often be installed with a working life expectancy of three to five years, so many network administrators must guess which functions will serve them best in the long term.

This has led to a complicated trade-off between a cheaper product that meets today’s specifications and an over-specified, pricier product that should be future-proof. The finance department will often be left to choose, making a Return on Investment (ROI) call.

New environmentally friendly ranges of networking equipment, developed for a more energy-conscious marketplace, make things trickier still.

The hype surrounding energy efficiency means many manufacturers are jumping on the bandwagon, leaving customers with a bewildering choice.

If a network administrator is truly keen to save power, they should first recycle responsibly and choose a product manufactured using environmentally friendly materials.

In fact, the most important issue for the network administrator when choosing greener networking solutions is its efficiency in use, because this can also save money.

Determining the power efficiency of networking equipment is an essential part of figuring out how green a product may be.

Power supply efficiency indicates how much energy is wasted when powering the electronic components of the networking equipment. Power supplies can vary in efficiency from between 40 per cent and 80 per cent, which is considerable.

A highly efficient power supply can halve the total power needed by a switch. In addition, inefficiency generates heat, which in many cases must be extracted from a building or a server room using air conditioning.

This further increases both CAPEX and OPEX costs and clearly is less environmentally friendly. Network administrators must verify power consumption by comparing this on the product’s datasheets against other products of its type.

Environmentally friendly networking equipment should also include power saving functions.

Green switches use a variety of mechanisms to save power and these must be scrutinised when picking the greenest product on the market.

Such features include the ability to power down ports when they are not in use. This is an important item on the green checklist – many network administrators use 75 per cent of the total number of ports on a switch, withholding the remaining 25 per cent for future network expansion.

If these ports cannot be put into a power down mode or disabled manually, they will consume power even when they are not connected.

The length of the cabling is also a key specification for power saving, and switches that can detect cable length to drive less power through them.

So if the physical configuration does not demand cables of 100m, products that support this could yield incremental power savings.

Equipment that can switch off LEDs during a 24-hour cycle can also help cut power consumption, as often LEDs are not monitored so this can be an easy way to save power.

In addition to power consumption and efficiency, green products should also be economical for the wide range of network loads they must support.

Many power supplies are less efficient at low or full loads. Therefore, theor power saving features must operate efficiently from zero load, where there are no cables and there is full power saving functionality, to full load, where all ports are functional with 100m cables and all LEDs on.

Datasheets must also be checked for power consumption at various load levels. The networking administrator must therefore ensure they have checked the maximum power consumption, which should ideally stand at around 75 per cent loading for normal business use and five per cent loading in overnight mode.

If datasheets are examined carefully, a green networking product can be both effective and easy to use.

Melvyn Wray is senior vice president of EMEA marketing at Allied Telesis