Date: Tue, 19 Nov 1996 19:13:06 -0500 From: dennis@etinc.com (dennis) To: Tony Li <tli@jnx.com> Cc: isp@freebsd.org Subject: Re: changed to: Frac T3? Message-ID: <199611200013.TAA10070@etinc.com>
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T.Li writes... > You buy time with buffer space, and buffer space in a freebsd > enviroment is rather abundant. You've got hardware buffering, and OS > buffering, all which need to compensate for the time needed to service > the interrupts. > >Sorry, this just false. Buffering allows you to trade rate mismatches for >latency. Unfortunately, you have a hard latency limitation. So adding >4GBytes of buffering to your FreeBSD box does NOT make the routing protocol >more stable. buffering increases the inter-service time for hardware by the OS...how the OS gets the data from one interface to another is another matter. Clearly we're not talking about the same things here...Im not sure what you mean by routing protocol stablity. Are you talking about IP? BGP? or what? > > At T1 there is no issue, because you can buffer several full timeouts > worth of data. > >Yes, but so what? If you queue up my protocol packets then either I can't >get at them for several seconds. Alternately, if this is output buffering >and my protocol packets don't get out of the box for several seconds, I'm >equally toast. IP is largely self throttling, and queue management shouldnt allow for holding packets longer than the protocols allow for. > I think building a freebsd box with 1 100Mbs ethernet and 1very high > speed interface is fairly easy...because you can control the process > flow. > >I agree with the goal and the conclusion. I still don't believe that >you've got enough process level control that you can also make the box a >Web server, say and not endanger the protocols. What you fail to mention is "at what point". I dont think we're even asking that question...we're trying to figure out the capabiltiy with minimal processes running. Dennis
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