The way in which businesses use LANs is changing and the performance requirement at the edge of the network is becoming more demanding. IP Telephony and other collaborative applications are driving more traffic to the edge of the network. As file sizes continue to grow, users need more bandwidth. Quite simply, the convergence of voice, video, data, and storage enables users to do more from their desktop. Enterprises need to be able to address today's increased demands and still prepare for the unknown demands of tomorrow. By re-assessing how they're using the wiring closet, they can achieve both goals, and be assured that their investments will be protected for a long time to come.Power over Ethernet (PoE) technology provides power and data connectivity to devices such as Internet telephones, wireless access points, network cameras, security and lighting devices, and access control devices.Part of Nortel Networks BayStack 5000 Series, BayStack 5520 Switches are one rack unit high stackable 10/100/1000 Mbps Ethernet Layer 3 routing switches designed to provide high-density Gigabit desktop connectivity and Power over Ethernet capability to mid-size and large enterprise customers' wiring closets.The BayStack 5520-48T-PWR PoE Switch features 48 10/100/1000 BASE-T RJ-45 ports for desktop switching and four built-in SFP (Small Form Factor Pluggable) GBIC ports for uplink. Ports 45, 46, 47, and 48 offer configuration flexibility by allowing the network administrator to configure each port as either 10/100/1000 or make use of the built-in SFP GBIC. However, power will still be provided from ports 45-48 and can be used to troubleshoot or power any 802.3af compliant device that only requires power and not a data connection. As many as eight BayStack 5520-48T-PWR Switches can be stacked to achieve up to 384 10/100/1000 ports for highest-density desktop switching.