September 2017


Maybe you’ve heard that Power over Ethernet (PoE) is about to kick it up a notch. Actually, a few notches… because in 2018, the IEEE 802.3 folks are expected to pass their latest version called 802.3bt. Expected are two new PoE types: Type 3 for 60 watts, and Type 4 for 100 watts. Obviously, these new powering options will have an impact on network deployments, especially with far less AC power needed on the device side of things.

On the cabling side, there’s been much hand wringing around the 100 watt PoE and heat build-up. The good news is that everyone appears to be in agreement that our Cat6/Cat6A cables are more than capable of meeting the demands for this amount of power. Although elevated heat means higher signal loss, the major cabling manufactures are confident that all is well.

So what about your switch? It’s true that Cisco has a solution for all the PoE you can imagine, but do you really need a switch, or a midspan power injector? Keep in mind that heat negatively impacts performance by increasing signal loss, but it also causes aging. Reviewing the specs on a Cisco switch and then comparing them to the MTBF (mean time before failure), the PoE switch is measured to fail more than 25% earlier than the non-PoE switch. This means you’re buying a more expensive switch, and it’s going to fail sooner! Cost savings + quality performance makes a great argument for a midspan injector panel. Simply inserting one between the patch panel port and the switch port allows the panel to “inject” the PoE power into the cable, and handle the heat at the same time.

There are many manufacturers of midspan systems, but Altronix is so confident they can handle any power/heat demands that they offer lifetime warranties for all of their products. Keeping the heat away from your expensive switch may take up more real estate in your racks, but you’ll increase the life of your switch by years.

– Mike


Here are some resources for expanded learning:

From CommScope: a PoE white paper

From Hubbell: a PoE technology publication

From Altronix: specifications for their NetWay16V Midspan Injector