Cisco Systems 3.2 manual Power over Ethernet, Pico Cell Functionality

Chapter 1 Overview

Power over Ethernet

Power over Ethernet

Lightweight access points can receive power via their Ethernet cables from 802.3af-compatible Power over Ethernet (PoE) devices, which can reduce the cost of discrete power supplies, additional wiring, conduits, outlets, and installer time. PoE also frees installers from having to mount Cisco 1000 series lightweight access points or other powered equipment near AC outlets, providing greater flexibility in positioning Cisco 1000 series lightweight access points for maximum coverage.

When you are using PoE, the installer runs a single CAT-5 cable from each lightweight access point to PoE-equipped network elements, such as a PoE power hub or a Cisco WLAN Solution Single-Line PoE Injector. When the PoE equipment determines that the lightweight access point is PoE-enabled, it sends 48 VDC over the unused pairs in the Ethernet cable to power the lightweight access point.

The PoE cable length is limited by the 100BASE-T or 10BASE-T specification to 100 m or 200 m, respectively.

Lightweight access points can receive power from an 802.3af-compliant device or from the external power supply.

Pico Cell Functionality

A Pico Cell is a small area of wireless provisioning provided by antenna, which allows for a dense high-bandwidth deployment for installations such as stock exchanges. Pico Cell wireless configurations require a specific supplicant to function correctly with Pico Cell environments. Off-the-shelf laptop supplicants are not supported.

Note Do not attempt to configure Pico Cell functionality within your wireless LAN without consulting your sales team. Non-standard installation is not supported.

Note Do not change the configuration database setting unless you are committing to a Pico Cell installation or without the advice of Cisco technical support.

Pico Cell functionality includes optimization of the operating system (operating system) to support this functionality as follows:

•The Cisco WCS Pico Cell Mode parameter reconfigures operating system parameters, allowing operating system to function efficiently in pico cell deployments. Note that when the operator is deploying a pico cell network the operating system must also have more memory allocated (512 to 2048 MB) using the config database size 2048 CLI command.

•Client mobility between multiple mobility domains when such exist.

•Addition of a WPA2 VFF extension to eliminate the need to re-key after every association. This allows the re-use of existing PTK and GTK.

•With WPA2 PMK caching and VFF, the PMK cache is transferred as part of context transfer prior to the authentication phase. This allows expedited handoffs to work for both intra- and inter-Cisco Wireless LAN Controller roaming events.

•A beacon/probe response that allows a Cisco 1000 Series lightweight access point to indicate which Cisco Wireless LAN Controller it is attached to so that reauthorization events only occur when needed, minimizing inter-Cisco Wireless LAN Controller handoffs and thus reducing CPU usage.

Cisco Wireless LAN Controller Configuration Guide

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