Dell's PowerConnect 6024

With the outstanding performance numbers and extensive feature set offered by its new PowerConnect 6024 Layer 3 switch, it's getting easier to hear the words "Dell" and "Gigabit Ethernet switch" in the same sentence.

The 24-port PowerConnect 6024 switch hit the streets last month and is targeted for data center server connectivity, wiring closet aggregation and as a core switch for smaller networks or branch offices. It features serious routing protocol support, physical redundancy, quality of service (QoS ) and access control lists (ACL), all for about $3,500. Our only complaint is that it lacks a high-bandwidth stacking backplane that would improve its overall bandwidth scalability.

The switch comprises a 19-inch box with all 24 10/100/1000 ports positioned on the front of the unit. For administrative access, it has a serial port, but it also offers a 10/100M bit/sec Ethernet port as an optional console port. This alternate interface is much faster than the serial port for issuing command-line instructions and means you don't have to dedicate another Gigabit port if a separate administrative network is mandated for security  purposes.

The PowerConnect 6024 offers a typical bundle of Layer 2 features including 802.1Q virtual LAN (VLAN) support, 802.1ad link aggregation support, and standard and Rapid Spanning Tree capabilities. At Layer 3, the switch supports Routing Information Protocol (RIP), Open Shortest Path First (OSPF) and Virtual Redundant Routing Protocol (VRRP ) specs. QoS is implemented with eight egress queues that can be configured with strict priority or Weighted Round Robin (WRR) queue servicing algorithms.

Both Layer 2 and Layer 3 throughput tests showed near wire-speed performance (See How we did it ). The switch hit 99.3% maximum throughput. At 7 microsec for 64-byte packets and 70 microsec for 1,518-byte packets, latency is low enough to support most enterprise applications.

In our test of the routing features, the PowerConnect 6024 handled a maximum of 2,050 RIP routes and 4,095 OSPF routes, very good numbers for a switch of this class. Route convergence for RIP and OSPF was stable and adjusted to large changes in routing information with ease.

The switch can implement ACLs based on Ethernet media access control address, IP address and TCP/User Datagram Protocol (UDP ) port number. As many as 1,024 ACLs can be configured within the switch and 1,024 entries can be added to each ACL. We didn't verify the switch's ability to configure 1,024 ACLs with 1,024 entries each - doing so would only test memory constraints. But we did configure a single ACL with 1,024 entries, assign that ACL to each physical interface, and run Layer 3 throughput and latency tests. Under these conditions, the PowerConnect 6024 only reduced its throughput to 97.7% for 64-byte packets. Latency did not change significantly.

In terms of QoS, the PowerConnect 6024 prioritizes packets based on 802.1p priority values or differentiated services code point (DSCP ) values. The queue-servicing algorithm can be configured as strict priority, WRR or a combination of both. We tested 802.1p and DSCP queuing features and found that the queuing algorithms operated properly for both strict priority and WRR.