The Nortel Ethernet Routing Switch 5510 (AL1001E04, Optivity line) models are 1 rack unit high next-generation stackable 10/100/1000 Mbps Ethernet Layer 3 routing switches designed to provide high-density Gigabit desktop connectivity to mid-size and large enterprise customers' wiring closets. The Nortel Ethernet Routing Switch 5510 is available in either a 24 or 48 port version.