24-port PoE Ethernet switches

Squirting electricity over the LAN is a brilliant idea with all manner of benefits. It allows administrators to simplify the deployment of things like wireless access points which have to be installed in ceilings and out of the way locations. It's a lot neater too, doing away with the need for those ugly 'wall warts' (AC adapters to you and me) and trailing wires that clutter up most offices these days.

Power over Ethernet (PoE) can also help you keep a lid on your electricity bills - an important consideration in the light of the recent massive price hikes.

But you can't just call in an electrician and get him to run a power lead to your patch panel - there's a little more to it than that. Infrastructure changes are required and you have to spend money on extra equipment.

That equipment needs to conform to the IEEE 802.3af standard for PoE (link to boxout), but can take a variety of forms. And that includes so-called mid-span hubs which sit alongside existing network switches and inject power into the wires coming from them.

For this group test, however, we've opted to look at switches with the necessary PoE circuitry built-in, eliminating the need for yet more boxes in already crowded communication racks.

All of the leading network vendors now offer such switches, in a variety of sizes and formats. For ease of comparison, though, we've stuck with 24-port products designed for edge of network deployment, gathering together a representative sample from half a dozen of the key manufacturers.

In terms of basic switching functionality they're a pretty diverse bunch, with a mix of Layer 2 and Layer 3 functionality as is common for corporate grade switches these days.

However it's the PoE support we're most interested in here. And that's what we tested, both by plugging in a variety of PoE devices to make sure they worked and using a custom tester supplied by PoE specialist PowerDsine (www.powerdsine.com). We've also paid close attention to the implementation of the PoE support, the number of devices that can be powered and management of the power features.

It's not an exhaustive test by any means. There are plenty of alternative products to be had, both from the vendors included here and others. It is, however, representative of what you'll come across when looking for edge switches with Power over Ethernet support and a good starting point for anyone in that position.