Date: Wed, 18 Feb 1998 08:47:42 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: eivind@yes.no (Eivind Eklund) Cc: brian@Awfulhak.org, eivind@yes.no, plm@xs4all.nl, freebsd-current@FreeBSD.ORG Subject: Re: cvs commit: src/usr.sbin/ppp command.c datalink.c datalink.h defs.h vars.c vars.h Message-ID: <199802180747.IAA02253@labinfo.iet.unipi.it> In-Reply-To: <19980218023234.65072@follo.net> from "Eivind Eklund" at Feb 18, 98 02:32:15 am
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> On Wed, Feb 18, 1998 at 01:08:30AM +0000, Brian Somers wrote: > > At the moment, ppp has four queues. Two IP queues and two modem > > queues. The IP queues are `interactive' and `normal', and the modem > > queues are `fast' and `normal'. LCP and `interactive IP' traffic > > goes into the `fast' modem queue. `fast' data gets delivered first. > > > > Wouldn't this be best approached by just having a dynamic MTU - one > > that varies based on the number of packets in the interactive queue ? > > The basic idea is sound, but it's the wrong variation parameter. You should The problem on slow links is that your interactive packet can arrive right after the transmission of a 1500 byte packet has started, and at that point you get .5-1s of delay just waiting the completion of the previously started transmission. Even if you use adaptive MTU, it does not work well with the usual terminal traffic e.g. when you read something, since you type one char, then read/think for a few seconds, etc. Being on a ppp link enables you to interrupt a packet exactly when you need to. cheers luigi -----------------------------+-------------------------------------- Luigi Rizzo | Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it | Universita' di Pisa tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/ _____________________________|______________________________________ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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