huge difference using wanproxy throught internet

[Daniel Coletti]

Hi,
    We're testing wanproxy heavily and during the tests we saw a baffling
traffic saving difference between using wanproxy inside a LAN and using it
trought the internet.

Under Linux (ubuntu 12.04 client side and debian 7.0 on the server).
The first set up is like this (we used an iso file for testing):
WPclient->(gateway)->//internet//->WPserver+squid->//internet//->webserver

1st. download:
traffic between wanproxies = 218.000 tcp packs, 183 mbytes
traffic between wanproxy client and PC inside the LAN = 29.412 tcp packs,
177Mb

2nd download:
about 10% traffic saving equally disperse between tcp packs and mbytes sent
between wanproxies

the second set up is like this (the same iso file):
WPcliente->(LAN)WPserver+squid->(LAN)->webserver
1st. download:
traffic between wanproxies = 104.000 tcp packs, 143 mbytes
traffic between wanproxy client and PC inside the LAN = 7844 tcp packs,
177Mb

2nd download:
traffic between wanproxies = 8230 tcp packs, *10* mbytes
traffic between wanproxy client and PC inside the LAN = 4090 tcp packs,
176Mb

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.

Following Diego Woitasen's advice I tried manipuling the MTU with MSS
Clamping (http://lartc.org/howto/lartc.cookbook.mtu-mss.html) and it got
better (up to 30% savings).

Using internet the number of tcp packets sent between wanproxies grew from
104K  (in LAN) to 218K (more than 100%).

Any ideas on how to go around this problem? Is there something that can be
done inside wanproxy's code?

thanks,

dc//

-- 
Daniel Coletti
Director
XTech (Soluciones Linux para Empresas) - http://www.xtech.com.ar
++(5411) 5219-0678
25 de Mayo 460 - 3er. piso
Buenos Aires, Argentina
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