Power over Ethernet (PoE)

Hello Abdul

In the past, many IP cameras, IP Phones, wireless access points would come with their own passive PoE injector. This was primarily done because such a passive injector is cheaper and more readily deployable. However, in recent years, more and more network device vendors have been incorporating active PoE using the IEEE 802.1af and other related standards, so today you will find that most good quality network devices will support this.

It is best practice to use the IEEE standards with switches because you can provide uninterruptible power to a switch, and have that switch in turn provide uninterruptible power to all of the devices it powers. This is more difficult to achieve using passive PoE injectors.

Switch vendors, including Cisco sell switches that support the IEEE PoE standards. As far as Cisco is concerned, each line of switches comes with different models, and some models support PoE. When looking at the datasheet for the 9300 series switches, for example, you can see the list of models available and which ones are PoE capable.

Switches that support passive PoE are rare, and typically not used in high-end reliable networks.

I hope this has been helpful!

Laz