Date: Sat, 28 Jul 2001 22:37:54 -0700 From: "Ted Mittelstaedt" <tedm@toybox.placo.com> To: "kesu" <kesu@kesuki.dyndns.org>, <freebsd-questions@FreeBSD.ORG> Subject: RE: Need help limiting bandwith ARP uses over cable modem. Message-ID: <000b01c117f0$9d971a40$1401a8c0@tedm.placo.com> In-Reply-To: <20010728171513.Q10366-100000@kesuki.dyndns.org>
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How is any filtering that you do on your FreeBSD system going to affect the incoming ARP packets? They are STILL going to come in - even if you block them, your blocking them after your modem has received them and so accomplishing nothing. Even a crummy Pentium 200 can saturate a 10Mbt Ethernet pipe without noticing it and I doubt that your getting even close that throughput delivered to you via cable. Your BSD Ethernet interface is literally loafing along when it is recieving those 7,000 arp requests - it's not dropping the tcp packets as a result of those. If anything is, it's your cable modem. Those recieved arps are still going to be there whether you block them from your BSD box or not and if your cable modem is being affected by them it will continue to be affected by them, whether you block them or not. If you want to limit INBOUND arp bandwidth then complain to your ISP. Of course - you can limit outbound ARP bandwidth all you want - but unless your system is screwed it's not transmitting 64k of outbound arps. Further, I doubt that the "consistent experience" your looking for is for OUTBOUND bandwidth, I'm sure that what you care about is INBOUND bandwidth - and you have no control over how much of a percentage of that is used by arps. Ted Mittelstaedt tedm@toybox.placo.com Author of: The FreeBSD Corporate Networker's Guide Book website: http://www.freebsd-corp-net-guide.com >-----Original Message----- >From: owner-freebsd-questions@FreeBSD.ORG >[mailto:owner-freebsd-questions@FreeBSD.ORG]On Behalf Of kesu >Sent: Saturday, July 28, 2001 3:24 PM >To: freebsd-questions@FreeBSD.ORG >Subject: Need help limiting bandwith ARP uses over cable modem. > > >Well I have a very low bandwith cap on my cable modem, and as soon >as the modem reconnects i am flooded with about 7,000 ARP requests. >(in the first 3 minutes) this can literally cause any number of tcp >packets to get dropped. since arp tends to be more forgiving than >tcp (especially for realtime situations) I would like to cap the >ARP protocols bandwith usage to 64 Killobits per second in both >directions over the cable modems interface. >I have ipfw configured and in the kernel, and anyone who could tell me how >to limit the bandwith of ARP would really help me get a more consistant >experience from my cable modem. > >--- 12:00PM up 21 days, 11:49, 11 users, load averages: 0.00, 0.00, 0.00 >Fortune of the day: >"I'm all for computer dating, but I wouldn't want one to marry my >sister." > > >To Unsubscribe: send mail to majordomo@FreeBSD.org >with "unsubscribe freebsd-questions" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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