How we tested the switches

We assessed switches with 10 sets of tests covering L2 and L3 unicast performance; IGMP group multicast capacity; L2 and L3 multicast performance; NAC/802.1X; storm control; power consumption; switch manageability, security, and usability; and switch features. A detailed, complete methodology is available here.

In the L2 unicast performance tests, we configured each switch with a single VLAN encompassing all ports. We attached a Spirent TestCenter generator/analyzer to all 48 gigabit Ethernet and two 10-Gigabit ports on the switch and ran three sets of tests: all ports, gigabit ports only, and 10-gigabit ports only. We offered traffic to the gigabit ports in a fully meshed pattern and to the 10-gigabit ports in a meshed pattern. For each test, we conducted separate 60-second runs with 64-, 256- and 1,518-byte frames, and measured throughput, average latency and maximum latency for each frame length.

The L3 unicast performance tests were similar to the L2 unicast tests, except in this case we configured each switch port to use a different VLAN and IP subnet.

In the IGMP group capacity tests, we reverted to an L2 configuration, enabled IGMP snooping, and set the switch to act as an IGMP querier. In this test, 47 of 48 TestCenter Gigabit Ethernet ports joined some number of IGMPv3 groups; the 48th TestCenter port acted as a monitor to detect flooding.

After sending group membership (join) messages and waiting at least twice the switch's IGMP query interval, TestCenter's ScriptMaster software then offered multicast traffic to the switch's first 10-gigabit port, destined for all multicast groups. Per RFC 3918, if all groups received at least one frame, the test iteration was considered a pass. If loss or flooding occurred, the iteration was considered a failure. Using either a step or binary search algorithm, we repeated this procedure to determine multicast group capacity.

In the L2 multicast performance tests, we configured all switch ports to join a single VLAN, to use IGMP snooping, and to act as an IGMP querier. Then TestCenter's 48 gigabit ports joined 500 IGMPv3 groups (or fewer, depending on results from the group capacity test). After waiting at least twice the switch's IGMP query interval, TestCenter's ScriptMaster software then offered multicast traffic to the switch's first 10-gigabit port, destined for all multicast groups. Using a binary search algorithm, TestCenter determined the throughput rate. In a separate test, TestCenter measured average and maximum latency at the throughput rate.

In the L3 multicast throughput and latency tests, we configured each switch port to use a separate VLAN and IP subnet, enabled protocol independent multicast-sparse mode routing on each port, and set the switch to act as a PIM rendezvous point. The test setup and traffic pattern was similar to the L2 multicast test. We again determined the throughput rate and measured average and maximum latency at that rate.

To assess 802.1X/NAC support, we developed six scenarios that describe roles a switch might play as part of the NAC infrastructure. In this case we attached the switch to a Windows 2003 server running Juniper Steel-Belted Radius Enterprise Edition 6.1 (SBR). The SBR configuration used Windows Active Directory credentials to authenticate users.