From owner-freebsd-hackers Fri Sep 20 09:22:35 1996 Return-Path: owner-hackers Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id JAA21813 for hackers-outgoing; Fri, 20 Sep 1996 09:22:35 -0700 (PDT) Received: from etinc.com (et-gw-fr1.etinc.com [204.141.244.98]) by freefall.freebsd.org (8.7.5/8.7.3) with SMTP id JAA21778 for ; Fri, 20 Sep 1996 09:22:29 -0700 (PDT) Received: from ppp-089.etinc.com (ppp-089.etinc.com [204.141.95.148]) by etinc.com (8.6.12/8.6.9) with SMTP id MAA20916; Fri, 20 Sep 1996 12:28:47 -0400 Date: Fri, 20 Sep 1996 12:28:47 -0400 Message-Id: <199609201628.MAA20916@etinc.com> X-Sender: dennis@etinc.com X-Mailer: Windows Eudora Version 2.0.3 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: Joe Greco From: dennis@etinc.com (Dennis) Subject: Re: Routers - hardware received wisdom Cc: hackers@freebsd.org Sender: owner-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk >> Well, interfaces just queue packets for the OS, > >Yes :-) > >> so if you do your queue >> management properly, you discard packets based on age, and if you have >> enough memory to hold your bandwidth * hold_time you wont dump anything >> that shouldnt be dumped. > >No. If your CPU is overloaded, you will end up dumping data that >is valid and shouldn't be dumped, simply because you never have the >chance to deal with it. And queueing only buys you a very little bit, >because when it comes right down to it, if I can overload your router >for a second, I can probably overload your router continuously - making >any queueing you do utterly useless. Queue management IS the cpu load. Hardware drivers just queue...all you need is some simple filters to get around abnormal data. A slightly intelligent process... The issue with Ciscos it that their filters have high overhead...so you cant even filter when you come under attack! > >> However, what you're talking about is not real data... > >Until it starts coming in at you off the Internet, outside of your control. >THAT is the whole point. Thats not really what the guy asked....any router can be brought down under certain circumstances. Its like saying the FreeBSD can't handle a 100Mbs ethernet....It can, under normal circumstances... Dennis