Date: Fri, 18 Aug 2000 08:49:38 -0700 (PDT) From: Archie Cobbs <archie@whistle.com> To: Brian Somers <brian@Awfulhak.org> Cc: Archie Cobbs <archie@whistle.com>, Brian Somers <brian@FreeBSD.ORG>, cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG, brian@Awfulhak.orgg Subject: Re: cvs commit: src/usr.sbin/ppp README.changes mp.c Message-ID: <200008181549.IAA07643@bubba.whistle.com> In-Reply-To: <200008180654.e7I6sKF44766@hak.lan.Awfulhak.org> from Brian Somers at "Aug 18, 2000 07:54:20 am"
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Brian Somers writes: > > 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. If you're doing Van Jacobson header compression, for example, with connection ID compression, out of order packets can really screw things up. -Archie ___________________________________________________________________________ Archie Cobbs * Whistle Communications, Inc. * http://www.whistle.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
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