This section provides an overview of some considerations for planning a PoE application. For additional information on this topic, refer to the HP PoE/PoE+ Planning and Implementation Guide which is available on the HP Networking web site at www.hp.com/networking.
Some of the elements you may want to consider for a PoE installation include:
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Port assignments to VLANs
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Use of security features
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Power requirements
This section can help you to plan your PoE installation. If you use multiple VLANs in your network, or if you have concerns about network security, you should read the first two topics. If your PoE installation comes close to (or is likely to exceed) the system’s ability to supply power to all devices that may request it, then you should also read the third topic. (If it is unlikely that your installation will even approach a full utilization of the PoE power available, then you may find it unnecessary to spend much time on calculating PoE power scenarios.)
To get the best PoE performance, you should provide enough PoE power to exceed the maximum amount of power that is needed by all the PDs that are being used.
By connecting an external power supply you can optionally provision more PoE wattage per port and or supply the switch with redundant 12V power to operate should an internal power supply fail. A Power Supply Shelf (external power supply) can also be connected to these switches to provide extra or redundant PoE power.
See the HP PoE/PoE+ Planning and Implementation Guide for detailed information about the PoE/PoE+ power requirements for your switch.
If your network includes VLANs, you may want to assign various PoE-configured ports to specific VLANs. For example, if you are using PoE telephones in your network, you may want to assign ports used for telephone access to a VLAN reserved for telephone traffic.
You can utilize security features built into the switch to control device or user access to the network through PoE ports in the same way as non-PoE ports.
MAC Address Security: Using Port Security, you can configure each switch port with a unique list of MAC addresses for devices that are authorized to access the network through that port. For more information, refer to the chapter titled “Configuring and Monitoring Port Security” in the Access Security Guide for your switch.
You can use the configurable QoS (Quality of Service) features in the switch to create prioritization policies for traffic moving through PoE ports. The available classifiers and their order of precedence are show in Classifiers for prioritizing outbound packets.
Classifiers for prioritizing outbound packets
| Priority | QoS classifier |
|---|---|
| 1 | UDP/TCP application type (port) |
| 2 | Device priority (destination or source IP address) |
| 3 | IP type of service (ToS) field (IP packets only) |
| 4 | VLAN priority |
| 5 | Incoming source-port on the switch |
| 6 | Incoming 802.1 priority (present in tagged VLAN environments) |
For more on this topic, refer to the chapter titled “Quality of Service: Managing Bandwidth More Effectively” in the Advanced Traffic Management Guide for your switch.
Please see the Event Log Message Reference Guide for information about Event Log messages. To see these manuals, go to www.hp.com/networking. Auto search the model number for your switch, for example: “HP Switch 2920”, then select the device from the list and click on Product manuals. Click on the “User guide” link under Manuals.