SNMP and MIBS For 802.3af PoE
If your PoE devices don't include sufficient management tools, "802.3af has an MIB which can be used to monitor the power sourcing equipment," according to Legra's Lew. (A power sourcing piece of equipment does not necessarily have to support the 802.3af MIB in order to be 802.3af-compliant, Lew notes.)
The benefits of the 802.3af MIB, Lew says, "are that it can be used to monitor unexpected changes in the line condition or problems with the power source itself, such voltage overruns and underruns and powering status."
If you're planning to do management of PoE devices, be sure what you have or that what you are getting supports it. For example, Dan Park, Director of Wireless LAN and management systems for Intermec, says that Intermec's single-port PoE hubs typically don't have SNMP management or the capability to remotely turn off the Access Point, but their 6-port and 12-port hubs do.
On the other hand, he points out, the software in many of the newer "smart" Access Points let sysadmins do this type of control, so the SNMP issue isn't as essential. But, he adds, "It's always beneficial to have it as an option for the one time you need to do it this way."
The SNMP management tool that can talk to the PoE MIBS include high-end systems such as UniCenter and Tivoli or HP OpenView; and mid-range (in the thousands of dollars) programs such as WaveLink Mobile Manager.
"We give you a base-level tool for free, for configuring handhelds, Access Points, and doing a small set of SNMP tasks," says Park. "If you want something fancier, you'll buy a tool."
Legra's Albert Lew explains, "All that is needed is to compile the MIB into a manager like HP OpenView and then use it to control the device. That isn't highly integrated; third-party management solutions such as AirWave support the 802.3af MIB and can use it to control 802.3af Access Points; they don't really support wireless LAN switches all that well."