The method behind the metrics

To conduct the 1999 SwitchMetric tests, The Tolly Group connected each switch to a test bed outfitted with $1.35 million worth of Netcom Systems equipment.

The test bed was configured to determine each switch's full-mesh aggregate throughput - throughout with each port transmitting to and receiving data from every other port. This setup provided a maximum load, enabling us to determine a switch's throughput capability in a worst-case traffic scenario.

At the heart of the test bed were as many as six SmartBits Advanced Multiport Performance Tester/Analyzer/Simulators provided for the test by Netcom. The SmartBits devices were used to generate Layer 2 and Layer 3 IP and IPX traffic, as well as to receive data from the switches and record all results.

Engineers tested multiple vendor switches side by side, using five SmartBits test tool device stacks. Each stack comprised a mix of SmartBits gear; The Tolly Group used five SMB-2000 chassis-based testers and 15 smaller SMB-10s.

"This exercise demonstrates the ease with which you can configure multiple SmartBits testers to act in concert on a large throughput test," says Tom Callas, the Tolly Group engineer who coordinated the testing.

The Tolly Group used Netcom's Xstream advanced switch test to conduct Layer 2 mesh testing. For Layer 3 IP testing of 10/100M bit/sec Ethernet switches, we used Netcom's VLAN Advanced Switch Test. For Layer 3 IP tests of Gigabit Ethernet switches, engineers manually configured the test using SmartWindow, a Netcom application that enables users to manually craft a test and build their own traffic patterns. Likewise, all Layer 3 IPX testing was configured manually using SmartWindow.

Testing was conducted between March 16 and April 16.

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The Tolly Group

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