On Tue, Jun 28, 2011 at 1:24 PM, PC <paul4...@gmail.com> wrote: > I have found most/all modern 3g networks can achieve optimal download speed > within their latency limitations (<200ms domestic end-to-end is normal for > most today) when combined with a modern operating system that does automatic > TCP receive window adjustments based on per-flow characteristics. I never > had a problem getting ~2 megabit from EVDO-revA, and can get ~20 megabit > without issue from the new Verizon LTE network. (Windows XP is not modern). >
AFAIK, Verizon and all the other 4 largest mobile networks in the USA have transparent TCP proxies in place. My point was that if end-hosts had Hybla or something similar, these proxies can be removed providing a better end-to-end solution. Cameron > As for VSAT, most every vsat equipment manufacturer has TCP > acceleration/proxy support built into the satellite modem. They basically > forge acks at the hub site to buffer data from the server, then deliver it > it to the remote end in a continuous flow. Many also have protocol > optimizations for some of the more "chatty" protocols. If you use it, your > 10 megabit should be achievable for typical HTTP/FTP consumer internet > activities, and it's surprisingly fast. I've sustained 6 without issue on > VSAT, only limited by bandwidth available, doing a simple SCP file transfer. > > Of course, none of this is to the scale of transatlantic gigabit transfers > with a single flow... > > > On Tue, Jun 28, 2011 at 10:16 AM, Cameron Byrne <cb.li...@gmail.com> wrote: >> >> On Tue, Jun 28, 2011 at 9:11 AM, Leigh Porter >> <leigh.por...@ukbroadband.com> wrote: >> > >> > >> >> -----Original Message----- >> >> From: Cameron Byrne [mailto:cb.li...@gmail.com] >> >> Sent: 28 June 2011 16:53 >> >> To: Leigh Porter >> >> Cc: Andreas Ott; Eugen Leitl; williamejs...@googlemail.com; NANOG list >> >> Subject: Re: [pfSense Support] Strange TCP connection behavior 2.0 RC2 >> >> (+3) >> >> In the 3G world, i have had good results overcoming longish RTT by >> >> using the Hybla TCP algorithm http://hybla.deis.unibo.it/ >> >> >> >> I am hoping it gets more default traction, especially in wireless >> >> where the radio link is a pretty big latency source >> >> >> >> Cameron >> > >> > How do you implement this for lots of clients and servers that have out >> > of the box implementations? The FastSoft box is a TCP man-in-the-middle box >> > that essentially implements the FAST TCP algorithm without either end >> > having >> > to worry about it. >> > >> >> You don't, the full benefits only come with a Linux kernel patch. The >> good news is that it only has to be implemented on the client end. >> >> > I have also used home-fudged TCP proxies with some success. >> > >> > Some 3G/wireless/VSAT vendors implement their own TCP modification >> > stacks but they usually only fiddle with window sizes and such. >> > >> >> That's why i said i hope it catches on as default :) If Android >> implemented Hybla, i think it would be a great improvement for user >> experience. Nobody likes the middleboxes that proxy TCP.... they cost >> money, don't scale well, and are generally fragile. Hybla is not a >> solution for the OPs issue, just a solution for high RTT links where >> the client can do Hybla. It an evolutionary step that i think would >> make a great fit in smartphones like Android. >> >> Cameron >> > -- >> > Leigh >> > >> > >> > ______________________________________________________________________ >> > This email has been scanned by the MessageLabs Email Security System. >> > For more information please visit http://www.messagelabs.com/email >> > ______________________________________________________________________ >> > >> > >
