Abstract

Extreme Networks, Inc. commissioned The Tolly Group to evaluate the performance of its BlackDiamond 6808 Switch configured with 48 Gigabit Ethernet ports and to compare the results to those of a Cisco Systems, Inc. Catalyst 6509 switch with 256 Gigabit Crossbar Fabric, also with 48 ports. 

This Tolly Group competitive evaluation examines Layer 3 IP multicast routing performance on the Extreme Networks BlackDiamond 6808 versus the Cisco Catalyst 6509 with Distributed Forwarding Card. Tested in July 2001, the report focuses on a demanding backbone-switching scenario: sustained Gigabit Ethernet multicast forwarding across 48 ports, both in pure multicast mode and in a mixed environment carrying simultaneous unicast and multicast traffic. The BlackDiamond 6808 was configured with 48 Gigabit Ethernet ports and compared directly against a 48-port Catalyst 6509 in the same test conditions.  

In multicast-only testing, Tolly measured traffic from a single multicast source to 47 receiving ports using both 64-byte and 1,518-byte packets. The BlackDiamond 6808 delivered 100% of theoretical maximum throughput in both cases, forwarding 69,940,465 packets per second with 64-byte packets and 3,819,878 packets per second with 1,518-byte packets. By contrast, the Catalyst 6509 forwarded only 10,763,799 packets per second and 587,876 packets per second respectively, equal to just 15.3% of theoretical maximum throughput for both packet sizes.    

The report also evaluated a mixed 50% unicast and 50% multicast traffic profile, with 47 ports exchanging bidirectional unicast traffic while one additional port simultaneously sent multicast traffic to the same receivers. In this scenario, the BlackDiamond again sustained zero-loss wire-speed throughput, achieving 69,940,465 packets per second with 64-byte packets and 3,819,878 packets per second with 1,518-byte packets. The Cisco platform reached only 29,469,135 packets per second and 2,441,313 packets per second respectively.  

Latency results also favored the Extreme platform. At 100% load, the BlackDiamond measured 20.8 microseconds with 64-byte packets and 48.4 microseconds with 1,518-byte packets, compared with 2,589.6 and 1,996.6 microseconds for the Cisco switch. Using zero-loss throughput, the BlackDiamond maintained the same 20.8 and 48.4 microseconds, while Cisco measured 25.7 and 92.8 microseconds. Overall, the report presents the BlackDiamond 6808 as a non-blocking, wire-speed multicast Layer 3 switch for high-volume enterprise backbones.