Cisco's Catalyst 6500 raises the stakes

Cisco might be a relative latecomer to 10G Ethernet switching, but it's hardly playing catch-up. Our exclusive lab tests show that new line cards and management modules for Cisco's Catalyst 6500 switches push the performance envelope in a number of ways:

•  Line-rate throughput with low delay and jitter. The Catalyst becomes only the second product tested to fill a 10G pipe.

•  Fast failover. The Catalyst set records for recovery times.

•  Perfect prioritization. The Catalyst is the only product that can protect high-priority traffic while simultaneously rate-limiting low-priority traffic.

•  IPv6 routing. In the first-ever public test of IPv6 routing, the Catalyst moved traffic at line rate even when handling 250 million flows.

The Catalyst's stellar performance in our tests, along with its rich feature set, earned it a World Class Award. Simply put, this is the highest-performing 10G Ethernet product we've tested to date.

To ensure an even comparison, we ran the same tests on Cisco's new gear - WS-X6704-10GE line cards and WS-SUP720 management modules - that we used in an assessment of 10G Ethernet products early this year (see here). Tests included pure 10G Ethernet performance; Gigabit Ethernet across a 10G Ethernet backbone; quality-of-service (QoS) enforcement; and failover times. For this review, we added failover and IPv6 forwarding and routing (see How we did it).

In the 10G Ethernet tests, we used Spirent Communications' SmartBits to generate traffic in a four-port, full-mesh configuration. Cisco's 10G Ethernet cards delivered line-rate throughput for all tests (see Table 1 ). That puts the Catalyst on par with the E1200 from Force10 Networks .

We should note that Cisco's 10G Ethernet cards are blocking - which causes frame loss - when all four ports exchange 64-byte frames between line cards. This was not an issue in our tests because we moved traffic between two ports on each of two cards. We think that's a fair comparison with previous products tested. Most of those had just one port per card, not four, so all previous tests were also across cards. Cisco says the new cards are nonblocking when handling a mix of frame sizes, but we did not verify this.

Delay and jitter with the Cisco 10G Ethernet cards weren't quite as low as previous record-holders from Foundry Networks and HP, but the numbers were well below the point at which application performance might suffer (see Table 2).

In the worst case (delay for 1,518-byte frames under 10% load), Cisco's average delay was 12.4 microsec, compared with 7.5 microsec for Foundry. Jitter was 0.5 microsec, compared with 0.6 microsec for Foundry in a similar test. Neither result will affect application performance.

We also conducted tests the way 10G Ethernet is most likely to be used - as a backbone technology. We built a test bed comprising two chassis connected with a 10G Ethernet link. Each chassis also had 10 (single) Gigabit Ethernet interfaces. We offered traffic from 510 virtual hosts to each Gigabit Ethernet interface, meaning there were 10,200 hosts exchanging traffic in a meshed pattern.