Interesting finding NIgel :).<br><br>I thought this is common within ISPs to cache internet traffic. This functionality of Transparent Proxying is possible even with Squid. Some time back this was a cool method to reduce the tier 1 bandwidth usage (most of the big guys were talking ab it). For most of the countries (unlike Korea and Japan... etc.) where internet traffic is not local, this was a must, including SL. Well most probably they use a commercial tool to do that :).<br>
<br>Nigel,<br><br>It would be interesting to trace the network path it takes over port 80. I'm stuck with a Windows box, can you give a try with hping on port 80 to do a path trace.<br><br># hping3 -S -t 0 -z -u 1 [IP Address] -p 80<br>
<br>You can use CTRL+z to increase the TTL. Or send me the IP address of the server you tested, so I can play with it once I go home<br><br>SInce we got in to the subject of caching... people who still haven't looked at Varnish, I suggest have a look. It was quite interesting.<br>
<br>Kosala<br><br><div class="gmail_quote">On Sun, May 3, 2009 at 4:37 PM, Nigel Gourlay <span dir="ltr"><<a href="mailto:ngourlay@gmail.com" target="_blank">ngourlay@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">I'm ambivalent about posting this mail, but the figures probably don't lie.<br>
<br>
The Qtel filter acts as both a censor and as a webcache. At a recent<br>
Qatar GNU Linux User Group meeting, I suggested it would be<br>
interesting to see how the filter affected download speeds.<br>
<br>
Tested using 1024kbps ADSL, contacting a US-located webserver bound to<br>
ports 80 and 92. Port 80 traffic is intercepted by Qtel's filter. Port<br>
92 traffic is ignore by Qtel.<br>
<br>
Static requests are HTTP GET requests for zero-byte and 100KB binary<br>
files. The responses should be cacheable by a webcache.<br>
<br>
Dynamic requests are HTTP GET requests to randomly generated URLs. The<br>
responses should not be cacheable.<br>
<br>
ICMP ping<br>
round-trip min/avg/max/stddev = 277.523/280.222/286.745/1.863 ms<br>
<br>
Zero-byte static requests<br>
Port 80: min/avg/max/stddev 60.673/68.117/198.970/18.626 ms<br>
Port 92: min/avg/max/stddev 581.702/598.875/1497.643/90.853 ms<br>
<br>
100KB static requests<br>
Port 80: min/avg/max/stddev 1179.798/1446.170/1791.680/113.822 ms<br>
Port 92: min/avg/max/stddev 3745.255/4205.562/6069.717/563.729 ms<br>
<br>
Zero-byte dynamic requests<br>
Port 80: min/avg/max/stddev 323.830/382.158/1627.435/173.142 ms<br>
Port 92: min/avg/max/stddev 584.414/626.839/1716.627/130.719 ms<br>
<br>
100KB dynamic requests<br>
Port 80: min/avg/max/stddev 1882.814/1914.729/2000.469/28.852 ms<br>
Port 92: min/avg/max/stddev 2450.092/2491.407/2530.966/17.465 ms<br>
<br>
<br>
Qtel's filter improves speeds for both static and dynamic requests.<br>
<br>
--nigel<br>
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</blockquote></div><br><br clear="all"><br>-- <br>Kosala<br>--------------------------------------------<br>Disclaimer: Views expressed in this mail are my personal views and they would not reflect views of the employer. <br>
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