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Network World - As data center managers consolidate and virtualize their servers, the next order of business becomes moving all that traffic. Enter top-of-rack data center switches that offer speed, scalability, redundancy, virtualization support and other features not available in garden-variety Ethernet switches.
This test analyzes switches, each sporting at least 24 10Gigabit interfaces, from Arista Networks, Blade Network Technologies, Cisco, Dell, Extreme and HP. We compared these products 10 different ways and subjected them to three months of grueling performance tests.
While each offered some standout qualities, we're singling out Arista's DCS-7124S and Blade's G8124 as top picks. With the best combination of features and performance – especially in the areas of latency and jitter – both switches earn Clear Choice awards. The Dell and Extreme entries also fared well.
The biggest surprises came from Cisco and HP. Cisco's Nexus 5010 is the only switch tested with a complete story on data/storage convergence, and its lengthy features list includes some outstanding virtualization capabilities. But high latency, usability gremlins and multicast leakage all hampered the Nexus 5010 in this test. HP ProCurve's 6600-24XG was only a modest performer. Although it was tops in media access control (MAC) address scalability, it was the only switch not to offer line-rate throughput, either for unicast and multicast traffic.
To help compare switches, we asked vendors to complete an extensive features questionnaire (see results). While vendors responded to more than 100 questions, we'll focus here on the major differentiators.
First, though, it should be noted that we decided not to compare vendors on price because actual pricing varies so much from list price.
The Arista, Blade and Cisco switches accept both gigabit and 10G Ethernet transceivers, a useful feature as data centers migrate from the gigabit connections found in the majority of servers today to 10G links which are likely to appear in the next year or two, especially as these begin to be embedded on server motherboards.
Cisco's Nexus 5010 is the only switch tested that offers native Fibre Channel interfaces and full Fibre Channel over Ethernet (FCoE) support. Fibre Channel options include 2G, 4G and 8G versions. All other switches can forward FCoE traffic, but that's a bit like saying an Ethernet switch supports IPv6 even though it's unaware the frames it forwards contain IPv6 headers.
All switches support redundant power supplies, and all except Extreme's offer redundant fans. The Arista and Blade designs also offer redundant out-of-band management ports. Fans in the Arista, Cisco, Dell and HP switches are hot-swappable.
Airflow is a concern in data centers, and vendors take differing approaches to keep their switches cool. The Arista, Blade and HP switches can be configured to blow air from front to back or vice-versa, depending on whether the switch faces a hot or cold row. Cisco's switch also reverses the orthodox design so that interfaces are at the back of the switch, alongside the power supplies; Cisco says this minimizes clutter.