How Labs Tested the Summit 48si.(Extreme Networks' network switch)(Hardware Review)(Evaluation)

Testing 10/100M-BPS ethernet switches is not nearly as boring as it might sound. During eWeek Labs' tests of the Extreme Summit 48si, we used Spirent Communications Inc.'s SmartBits hardware and SmartFlow software to test the new Layer 3 features.

To gauge the performance of the Summit 48si--including the number of supported multicast sessions, quality-of- service and rate-limiting capabilities as well as such security features as access control lists and virtual LANs--we used a series of standard tests that incorporated some twists. For example, the default setup for SmartFlow, a test suite that generates repeatable, measurable network traffic flows, is to have one IP address assigned per flow. We used 20 IP addresses per flow on the Summit 48si to more realistically stress the device.

We also juiced up the tests by using random packet sizes ranging from 64 bytes to 1,518 bytes. We saved these configurations so we could run them on the Extreme switch and on other vendors' devices to get roughly comparable results. Random packet sizes make switch hardware "think" more, which yields a better prediction of performance under real network loads.

Still, these tests are mere attempts at simulating the real world because it is just as unlikely that a switch will encounter completely random packet sizes in all traffic as it is that all the packets will be perfectly formed and of uniform length.

Further, different configuration parameters among the Cisco Systems Inc., Extreme Networks Inc. and Foundry Systems Inc. equipment made test results only approximations of relative performance. IT managers should know the characteristics of the traffic on their network--the amount, likely packet size, security rules and user restrictions--and use that information to make decisions about performance.