Selectable Power over Ethernet ClassesBy John Honovich, Published on Feb 09, 2010
As cameras offer more options (storage, analytics, etc.), their power needs will certainly rise. This poses a problem for appropriately measuring and setting up power draw for PoE switches. NetworkWebCams has a good explanation of the benefits of Selectable PoE classes.
The example they provide is for Mobotix 24 series cameras that allow for selecting the specific PoE class (see table breaking down PoE classes). Mobotix is an interesting example because of their increasing support for greater functionality.
By setting specific classes, deployments can granularly control how much power each IP camera uses. For instance, by setting Class 1, power consumption will be no more than 4 watts. By contrast, setting Class 0 can consume 300% more power.
PoE switches often do not support maximum power consumption for powering all IP cameras at maximum power. For example, a 4 port PoE switch may be rated for 30 watts but those 4 cameras might need up to 60 watts.