From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Carlson Subject: Re: [Patch] fix packet loss and massive ping spikes with PPP multi-link Date: Fri, 26 Mar 2010 13:04:24 -0400 Message-ID: <4BACE918.7020508@workingcode.com> References: <2d460de71003260850x7f90d04cy79ac853464108182@mail.gmail.com> <20100326160226.0159ac3b@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: Alan Cox , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, linux-ppp@vger.kernel.org To: Richard Hartmann Return-path: In-Reply-To: Sender: linux-ppp-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Richard Hartmann wrote: > Also, I am not sure if it would not be better to default to no > fragmentation and enable it optionally. I am aware that changing default > behaviour is always a bit of a problem but to the best of my knowledge > enabling fragmentation is a bug in any and all real-world applications. It worked well and was enabled by default on all the Bay Networks equipment I used ~15 years ago. And I know for certain that we tested with other gear (Ascend and Clam, probably) that did it right. If it works with the equipment you're using, it's a useful feature in that it can balance out the latencies among the links, resulting in much lower overall latency observed by higher layers -- especially so on lower-speed links where MP is more likely to be used. Without it, you're left either waiting for the one slow link choking on a big packet to catch up, or (worse) disabling the sequence headers altogether, resulting in reordering unless you're really "clever." It's a darned shame that lame implementations would force a change in the default ... -- James Carlson 42.703N 71.076W