Date: Mon, 12 Feb 2001 11:02:52 -0800 (PST) From: wpaul@FreeBSD.ORG (Bill Paul) To: bj@zuto.de Cc: ticso@cicely.de, net@FreeBSD.ORG Subject: Re: call for testers: port aggregation netgraph module (fwd) Message-ID: <20010212190252.2430F37B491@hub.freebsd.org> In-Reply-To: <Pine.NEB.3.96L.1010211222117.30518f-100000@fledge.watson.org> from Robert Watson at "Feb 11, 2001 10:21:40 pm"
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> Date: Sat, 10 Feb 2001 15:29:17 +0100 > From: Rainer Clasen <bj@zuto.de> > To: net@FreeBSD.ORG > Cc: ticso@cicely.de > Subject: Re: call for testers: port aggregation netgraph module > > On Thu, Feb 08, 2001 at 01:25:09PM -0800, Bill Paul wrote: > > http://www.freebsd.org/~wpaul/FEC/4.x/fec.tar.gz > > I've tried this with 4.2-RELEASE on a single PIII-500 with 128 MB RAM and > 2 fxp0 Interfaces. It was attached to a Nortel Baystack 450 running a 2 > port "Multinlink Trunk" Configuration. > > It worked absolutely flawlessly. Ok... > When downloading a single 60MB file to 3 clients by FTP, it achieved > ~21 MB/sek output (netstat -I fec0 -w10). I had to use 3 clients due to > lack of a second speedy client. > > I'm impressed. So am I. > Am I right that a single transfer is always limited to the bandwidth of a > single interface? The above mentioned Switch and Linux ditribute traffic > in a round robbing manner. Both cooperate with Cisco's Etherchannel > (tested against a Catalyst 2924). How about adding a round robbing > distribution, too? This is epecially usefull for getting higher throughput > when traffic mostly takes place between 2 hosts. You are correct in your assumption. The port selection is done by XORing the lower bits of the source and destination addresses in the packet (either MAC address or IP address). So all packets transmitted to a given host will always be sent over the same interface in the bundle (unless it's down, in which case it'll use the next one over). As for using a round-robin distribution... well, the idea behind etherchannel is to distribute the traffic across multiple links while preventing any out-of-order packet transmissions with minimal work. Using a round-robin scheme would require some sort of mechanism to deal with preserving packet ordering. Adding another port selection scheme should be pretty simple as long as somebody can point me at the right algorithm. -Bill To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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