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Showing posts from February, 2012

Alternatives to Cisco for 10 Gb/s Servers

This is a post written in response to Chris Marget's well done series "Nexus 5K Layout for 10Gb/s Servers". While I appreciate the detail and thought that went into the Cisco-based design, he's clearly a "Cisco guy" showing a teensy-weensy bit of bias toward the dominant vendor in the networking industry. The end result of his design is a price that is over $50K per rack just for networking - approaching the aggregate cost of the actual servers inside the rack! Cisco is the Neiman Marcus of the networking world.

So I came up with an alternate design based on anything-but-Cisco switches. The 10G switches from Arista here use Broadcom's Trident+ chip, which supports very similar hardware features as the Cisco solution (MLAG/vPC, DCB, hardware support for TRILL if needed in the future, etc.). Many other vendors offer 10G switches based on this merchant silicon, such as Dell/Force10 and IBM. Because this is commodity switching silicon which BRCM will sell t…

Bufferbloat on a 3G network

I've been experiencing terrible network performance lately on Sprint's 3G (EVDO) network in downtown Chicago. I have both a Sprint Mobile Broadband card for my laptop and an iPhone 4S on Sprint's network. Sprint performance used to be fantastic compared with AT&T and Verizon mobile data networks in Chicago, but the introduction of the iPhone on Sprint seems to have caused some capacity problems. The worst spot I've come across seems to be the Ogilvie train station.

I decided to run some diagnostics from my laptop in the area during a busy rush hour. I expected to see that the network was just hopelessly oversubscribed, with high packet loss. This is a very busy commuter train station, and there are probably tens of thousands of 3G smart-phones in the vicinity at rush hour. There's also lots of mirrored glass and steel in the high-rise buildings above - basically it's the worst "urban canyon" radio environment imaginable.

However, some simple ping …