Date: Wed, 2 Mar 2005 18:58:02 +0100 (CET) From: Lars Erik Gullerud <lerik@nolink.net> To: Lister <lister@primetime.com> Cc: freebsd-performance@freebsd.org Subject: Re: ng_fec and cisco 2931 Message-ID: <20050302174915.V38850@electra.nolink.net> In-Reply-To: <4222C64D.4050007@primetime.com> References: <4222C64D.4050007@primetime.com>
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On Sun, 27 Feb 2005, Lister wrote: > > I have setup ng_fec on a machine with a quad ethernet NIC : [snip] > I have all 4 ports connected to the catalyst. From what I have read on > fast etherchannel in the cisco docs, it is supposed to detect the > etherchannel, > e.g. no commands at the switch. Lights blink on and off, change color > (orange -> green) and it seems to work ... but only on one interface in the > bundle. No faster than 80Mb. I have a 1000Mb intel card in the 2nd > test machine that does run much faster than 100. > So, is there something I have done wrong, or what? What should I expect > to get from 4 x 100 Mb ports? Not really related to FreeBSD's ng_fec at all I think, this is a common FEC issue. If you are testing this between two hosts as you indicate above, then you are getting exactly the speed you should be getting. The low-end Cisco switches offers two varieties of "load-balancing" over the FEC members, source or destination-based hash (both operate on MAC-address level). So if all your test traffic goes between a set of two mac-addresses, traffic in either direction will only flow over one member of the FEC. The higher-end devices like the 6500 series can also look at layer 3 and layer 4 flow-information to distribute the load, but basically a FEC is mostly useful in scenarios where you have a large number of hosts communicating. /leg
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