From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from bifrost.lang.hm (mail.lang.hm [64.81.33.126]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by huchra.bufferbloat.net (Postfix) with ESMTPS id 0DC2521F5C7 for ; Sat, 23 Aug 2014 22:15:00 -0700 (PDT) Received: from asgard.lang.hm (asgard.lang.hm [10.0.0.100]) by bifrost.lang.hm (8.13.4/8.13.4/Debian-3) with ESMTP id s7O5EssO029549; Sat, 23 Aug 2014 22:14:59 -0700 Date: Sat, 23 Aug 2014 22:14:54 -0700 (PDT) From: David Lang X-X-Sender: dlang@asgard.lang.hm To: Hal Murray In-Reply-To: <20140824034935.7D41E406060@ip-64-139-1-69.sjc.megapath.net> Message-ID: References: <20140824034935.7D41E406060@ip-64-139-1-69.sjc.megapath.net> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: bloat@lists.bufferbloat.net Subject: Re: [Bloat] sigcomm wifi X-BeenThere: bloat@lists.bufferbloat.net X-Mailman-Version: 2.1.13 Precedence: list List-Id: General list for discussing Bufferbloat List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 24 Aug 2014 05:15:00 -0000 On Sat, 23 Aug 2014, Hal Murray wrote: >>> Yep... I remember a neat paper from colleagues at Trento University that >>> piggybacked TCP's ACKs on link layer ACKs, thereby avoiding the collisions >>> between TCP's ACKs and other data packets - really nice. Not sure if it >>> wasn't just simulations, though. > >> that's a neat hack, but I don't see it working, except when one end of the >> wireless link is also the endpoint of the TCP connection (and then only for >> acks from that device) > > That could be generalized to piggybacking any handy small packet onto the > link layer ACK. > > Of course, then you have to send back a link layer ACK for the extra info. > Does that converge? if you aren't talking between the two endpoints of the wireless connection, probably :-) but fairness would be an issue for something like this. what constitues a 'small amount of data' to try and piggyback, and what happens if you are talking between endpoints, are the two allowed to monopolize the airtime? but backing up a step, finding airtime for the ack is just as hard as finding airtime for the next transmission. David Lang