Abstract

Extreme Networks, Inc. commissioned The Tolly Group to benchmark the performance of its BlackDiamond 6808 Switch configured with 48 fiber Gigabit Ethernet ports. Extreme Networks requested that The Tolly Group measure the BlackDiamond 6808 switch for Layer 3 throughput and latency in a full-mesh configuration and compare the results to those of a Cisco Systems, Inc. Catalyst 6509 switch with 256 Gigabit Crossbar Fabric, also with 48 ports in a full-mesh configuration.

This Tolly Group price/performance evaluation compares the Extreme Networks BlackDiamond 6808 with the Cisco Catalyst 6509, tested both with and without Distributed Forwarding Card (DFC), in a 48-port Gigabit Ethernet fiber configuration. Commissioned by Extreme Networks and conducted in July 2001, the report focuses on three practical concerns for backbone and data-center switching: Layer 3 wire-speed throughput, latency under load, and cost per delivered Gigabit.  

In full-mesh, full-duplex testing across 48 Gigabit Ethernet ports, the BlackDiamond 6808 delivered 100% of theoretical maximum throughput for both 64-byte and 1,518-byte packets. Tolly measured 71.4 million packets per second, or an aggregate 96Gbit/s, with 64-byte traffic, and 3.9 million packets per second, also at 96Gbit/s, with 1,518-byte traffic. By comparison, the Cisco Catalyst 6509 with DFC reached 69% wire speed for 64-byte packets and 89% for 1,518-byte packets, while the version without DFC delivered 33% and 53% respectively. In aggregate terms, the Cisco system with DFC produced 66.24Gbit/s with 64-byte packets and 85.44Gbit/s with 1,518-byte packets; without DFC, it reached 31.68Gbit/s and 50.88Gbit/s.    

Latency measurements also favored the Extreme platform. The BlackDiamond 6808 showed 28 microseconds of average latency for 64-byte packets both at 100% load and at zero-loss throughput. The Cisco Catalyst 6509 with DFC measured 398 microseconds at 100% load and 15 microseconds at zero-loss throughput, while the non-DFC configuration measured 1,295 microseconds and 94 microseconds respectively.  

Tolly also calculated a “cost-per-Gigabit” metric using actual zero-loss throughput and switch cost. The BlackDiamond 6808 measured $978.59 per delivered Gigabit, compared with $1,966.31 for the Catalyst 6509 with DFC and $2,315.02 without DFC in the 1,518-byte test. The report concludes that the BlackDiamond 6808 combined wire-speed Layer 3 throughput with substantially lower cost per usable Gigabit in this 48-port Gigabit Ethernet backbone scenario.