Date: Fri, 20 Sep 1996 12:28:47 -0400 From: dennis@etinc.com (Dennis) To: Joe Greco <jgreco@brasil.moneng.mei.com> Cc: hackers@freebsd.org Subject: Re: Routers - hardware received wisdom Message-ID: <199609201628.MAA20916@etinc.com>
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>> 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
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