tinc for Satellite connections (benchmarking)

[Pau]

Hello.

I'm living in the country side where the communications are very very
poor. My only choice is Satellite connection throw the French company
Eurona which uses the network deployed by Skylogicnet.

In general the latency is very bad (~800ms) and the network is very
unstable. I have been investigating in the ISP routers which are in my
path and there are many hops which are done in a private network
(10.130.130.0/24). I think one or more of these hops are doing some kind
of HTTP proxy cache and also many dirty stuff like blocking some ICMP
messages and so on (thing that ends up in a MSS/MTU problem).

I don't like to see my end2end connections modified during the path so I
decided to set up a tinc network to transfer all the Internet data until
one of my servers placed in somewhere of Internet.

I'm using the following values for the layer3 tinc network:

Compression=11
PMTU=1480
Cipher=none
ClampMSS=no
ReplayWindow=32

The DNS are not routed using the tinc overlay, here you can check my
"tinc-up" script [1].

To test the difference between using tinc and using the raw connection I
have made a little script [2] which uses "httping" to calculate the time
needed to get a web site. I have taken the list of "most visited web
sites" from alexa.com. I made two tests for each kind of connection:

- 50 most visited sites
- 50 less visited sites

Here you can see the results [3]. In the 50 most visited, the clear
winer is the raw connection because of these web-cache proxies which are
somewhere in the path. However in the 50 less visited, the cache hits
are smaller and the results are very similar.

RAW: 2536 ms (average)
TINC: 2815 ms (average)

In addition, the TINC network is able to reach more sites (41 VS 46)!!
So probably it is a huge part of the difference between both results
(non reachable sites by RAW are usually reached by TINC with big latency).

In this point you would ask why am I saying all this stuff? Well, for
three points:

- It could be useful for someone
- I wanted to share it with some more people to see if someone has a
comment related to it
- I want to know from the tinc experts what more options might I modify
to optimize the connectivity

[1] http://pastebin.com/23XwwquB
[2] http://pastebin.com/h3w3URV1
[3] http://pastebin.com/JMWE2HMd

-- 
./p4u