On Thu, 28 Jun 2012, Brian Candler wrote: > On Thu, Jun 28, 2012 at 11:25:20AM +0200, Nicolas Sebrecht wrote: >> We excluded ethernet due to searches on the web. It appeared that >> ethernet has bad latency. > > I read it on the web, it must be true :-) > > As I said: don't use 10GE over CAT6/RJ45 (10Gbase-T). That does indeed have > poor latency. As I understand it: in order to get such high data rates over > copper, it has to employ mechanisms similar to DSL lines, like interleaving, > which means 10G has comparable or even higher latency than 1G. Switches > with all 10Gbase-T ports are expensive, only available from a couple of > vendors, and consume a lot of power. First gen PHYs did suck a LOT of power, but this has changed. With the next gen PHYs the cost of the 10GBase-T switches has also dropped. They are now the lowest cost switches out there. I like Arista Networks the best, but you can get a switch for well under 10K from guys like Interface Masters. New servers from SuperMicro and others now offer 10GBase-T native drastically lowering the cost per port. > I have been working with Intel X520-DA2 NICs and a Netgear XSM7224S switch, > and direct-attach cables (3m Netgear AXC763, 5m Intel) > > This all works fine, although with older versions of Linux I had to build > the latest Intel drivers from their website to fix problems with the links > going down every day or two. Ya, I ran into a odd problem with my X520s where everything worked except VLANs on bonded interfaces. It took me a full day to figure out it was not my switch or config, but the stupid ixgbe driver! ><> Nathan Stratton nathan at robotics.net http://www.robotics.net
