<div dir="ltr">2013/8/16 Juli <span>Mallett</span> <span dir="ltr"><<a href="mailto:juli@clockworksquid.com" target="_blank"><span>juli</span>@<span>clockworksquid</span>.com</a>></span><br>
<div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">
Hi Daniel,<div><br></div><div>With a lower-latency link like a WAN rather than the Internet, I would expect to see more packets sent between WANProxy instances; WANProxy makes no effort to buffer up data before sending it. Using a slower link, you'll naturally have more buffering occurring and fewer packets sent. There's some things that we could do and should do to avoid sending out gratuitous small packets, and I have some changes to do that, but I haven't tested them enough to check them in yet.</div>
<div><br></div><div>I'm not sure if I understand the difference you're seeing in terms of data reduction / deduplication / compression. Which is giving the greater savings in terms of data transferred, the LAN or the Internet? </div>
</div></blockquote><div><br></div><div>The LAN, definitely. the savings are enormous. In a 168Mb file transfer the first time there's 172Mb of traffic between <span>WANProxy</span> instances, the second time it doesn't even reach 2Mb. of data transferring.<br>
</div><div>Transfer time follows a similar pattern, 14 seconds the first download, 4.2 seconds the second one.</div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">
<div dir="ltr"><div> And what kind of download time are you seeing to the client on each configuration?</div></div></blockquote><div> </div><div>The transfer time evaluation is tricky using Internet because the link speed is not constant, well the link is but the links between the routers I jump to reach to the ending point might not. That's why I took a closer look in terms of data/<span>pkts</span> transfer.</div>
<div>Nevertheless the transfer time difference between first and second file transfer is not substantial.</div><div><br></div><div style>I dug a bit deeper and I found that what seems to be causing the problem is not the Internet o MTU, but http-proxy I use behind the WANProxy "server". </div>
<div style>If I change the setup from this:</div><div style>WPclient->(gateway)->//internet//->WPserver+squid->//internet//->webserver<br></div><div style>to this:</div><div style>WPclient->(gateway)->//internet//->WPserver->webserver<br>
</div><div><br></div><div style>and download the very same file, it worked like a charm. the second time the file downloaded a LOT faster.</div><div style>This time instead of being at some server on the internet I put it in a local webserver that lives in the same server as the ending point of WANProxy.</div>
<div style>But I can't figure out why this is causing problems, and huge ones.</div><div style><br></div><div style>downloading the same file twice using the first setup takes 10 to 20% less than the first time, when using the second setup the file is downloaded 60 to 70% faster at the second time.</div>
<div style><br></div><div style>If I use the ending http-proxy locally (that is by connecting via ssh to the server and using the local http proxy to download this very same file from the internet) the transfering is very fast. The internet connection of this server is a lot faster that the one I have at the gateway of my LAN.</div>
<div style><br></div><div style>Could it be that the communication between WANProxy end point with a http proxy creates too many packets between them, and this problem gets somehow translated to the WAProxy starting point "the client"?</div>
<div style><br></div><div style>I hope I explained myself, if not I'll try to send some "drawings" to explain the problem better. Please excuse my english.</div><div style><br></div><div style>thanks for any tips.</div>
<div style><br></div><div style>dc//</div><div>
<br></div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div dir="ltr">
<div><br></div><div>Thanks,</div><div>Juli.</div></div><div class="gmail_extra"><br><br><div class="gmail_quote"><div><div>On Fri, Aug 16, 2013 at 8:25 AM, Daniel Coletti <span dir="ltr"><<a href="mailto:dcoletti@xtech.com.ar" target="_blank">dcoletti@xtech.com.ar</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex"><div><div><div dir="ltr">Hi,<div> We're testing <span style="background-color:yellow">wanproxy</span> heavily and during the tests we saw a baffling traffic saving difference between using wanproxy inside a LAN and using it trought the internet.</div>
<div><br></div><div>Under Linux (ubuntu 12.04 client side and debian 7.0 on the server).</div><div>The first set up is like this (we used an iso file for testing):</div><div>WPclient->(gateway)->//internet//->WPserver+squid->//internet//->webserver<br>
</div><div><br></div><div><div>1st. download: </div><div>traffic between wanproxies = 218.000 tcp packs, 183 mbytes</div><div>traffic between wanproxy client and PC inside the LAN = 29.412 tcp packs, 177Mb</div><div><br>
</div>
<div>2nd download:</div><div><div>about 10% traffic saving equally disperse between tcp packs and mbytes sent between wanproxies</div></div></div><div><br></div><div>the second set up is like this (the same iso file):<br>
</div><div><span style="font-family:arial,sans-serif;font-size:13px">WPcliente->(LAN)WPserver+</span><span style="font-family:arial,sans-serif;font-size:13px">squid->(LAN)->webserver</span><br></div><div>1st. download: </div>
<div>traffic between wanproxies = 104.000 tcp packs, 143 mbytes</div><div>traffic between wanproxy client and PC inside the LAN = 7844 tcp packs, 177Mb</div><div><br></div><div>2nd download:</div><div><div>traffic between wanproxies = 8230 tcp packs, *10* mbytes</div>
<div>traffic between wanproxy client and PC inside the LAN = 4090 tcp packs, 176Mb</div></div><div><br></div><div>The first thing I notice was the huge difference in the tcp packs sent during the first download of both setups (Internet vs. LAN) 218K vs 104K, but the differences between the first and second download using LAN is 20% saving using internet, 95% saving using LAN.</div>
<div><br></div><div>Following Diego Woitasen's advice I tried manipuling the MTU with MSS Clamping (<a href="http://lartc.org/howto/lartc.cookbook.mtu-mss.html" target="_blank">http://lartc.org/howto/lartc.cookbook.mtu-mss.html</a>) and it got better (up to 30% savings).</div>
<div><br></div><div>Using internet the number of tcp packets sent between wanproxies grew from 104K (in LAN) to 218K (more than 100%).</div><div><br></div><div>Any ideas on how to go around this problem? Is there something that can be done inside wanproxy's code?</div>
<div><br></div><div>thanks,</div><div><br></div><div>dc//</div><span><font color="#888888"><div><br></div><div>-- <br>Daniel <span style="background-color:yellow">Coletti</span><br>Director<br><span style="background-color:yellow">XTech</span> (<span style="background-color:yellow">Soluciones</span> Linux para <span style="background-color:yellow">Empresas</span>) - <a href="http://www" target="_blank">http://www</a>.<span style="background-color:yellow">xtech</span>.com.<span style="background-color:yellow">ar</span><br>
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<span style="background-color:yellow">Buenos</span> <span style="background-color:yellow">Aires</span>, Argentina
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</blockquote></div><br><br clear="all"><div><br></div>-- <br>Daniel <span>Coletti</span><br>Director<br><span>XTech</span> (<span>Soluciones</span> Linux para <span>Empresas</span>) - <a href="http://www" target="_blank">http://www</a>.<span>xtech</span>.com.<span>ar</span><br>
++(5411) 5219-0678<br>25 <span>de</span> Mayo 460 - 3er. <span>piso</span><br><span>Buenos</span> <span>Aires</span>, Argentina
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