Date: Fri, 18 Aug 2000 07:54:20 +0100 From: Brian Somers <brian@Awfulhak.org> To: Archie Cobbs <archie@whistle.com> Cc: Brian Somers <brian@FreeBSD.ORG>, cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG, brian@Awfulhak.org Subject: Re: cvs commit: src/usr.sbin/ppp README.changes mp.c Message-ID: <200008180654.e7I6sKF44766@hak.lan.Awfulhak.org> In-Reply-To: Message from Archie Cobbs <archie@whistle.com> of "Thu, 17 Aug 2000 16:43:27 PDT." <200008172343.QAA00191@bubba.whistle.com>
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> Brian Somers writes: > > Modified files: > > usr.sbin/ppp README.changes mp.c > > Log: > > If we're in MP mode with a single open link, MP link level compression > > isn't open and the links MRU >= our MRRU, send outbound traffic as > > PROTO_IP rather than PROTO_MP. This shaves some bytes off the front > > of each packet 'till the second link is brought up. > > FYI- > Mixing MP frames with non-MP frames is slightly dangerous. The > problem is that the PPP link layer is required to deliver packets > in order. When you go from MP encapsulating packets to not MP > encapsulating packets (or vice-versa) you can't guarantee that the > peer will deliver the packets in the same order that you sent them > without being careful. This is mainly a problem when going from 1 > -> 2 links I believe... or when mixing MP and non-MP over multiple > links. It should only ever be possible to deliver out-of-order network layer frames here, and even then, only a single frame can be out of order at the time of the second link opening. I think the reason behind the link layer being required to deliver in order is so that the control protocol packets don't make a mess of the peers state machine (out of order IPCP frames for example). As ppp currently only does IP as an NCP, and IP packets are allowed to be delivered out-of-order, I think this is ok. > -Archie > > ___________________________________________________________________________ > Archie Cobbs * Whistle Communications, Inc. * http://www.whistle.com -- Brian <brian@Awfulhak.org> <brian@[uk.]FreeBSD.org> <http://www.Awfulhak.org>; <brian@[uk.]OpenBSD.org> Don't _EVER_ lose your sense of humour ! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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