# Simulating satellite uplink



## ericx (Jan 11, 2016)

I'm attempting to configure a multi-wan device to improve ship-to-shore data links via satellites. I would like to build a simulation environment so I can work on this before the ship finishes installing her dishes.

The satellite links are slow (56 kbps - 100 kbps) and some have round-trip latencies as high as 4-5 seconds. On top of that, the ship is in the practice of taking many turns which causes the dishes's LOS to the satellites to be eclipsed by parts of the superstructure (so the links blink on and off at long intervals).

I'm looking for a way to simulate as many as 4 of these awkward links and put them between a pair of the multi-wan devices for testing.


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## RedShift1 (Jan 11, 2016)

I had a similar requirement a few years ago and I used Wanem to do just that: http://wanem.sourceforge.net/


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## tobik@ (Jan 11, 2016)

Can dummynet(4) be used for that?


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## ericx (Jan 12, 2016)

Those are both excellent suggestions. I'm going to try dummynet first.


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## SirDice (Jan 12, 2016)

ericx said:


> Those are both excellent suggestions. I'm going to try dummynet first.


Not sure if the article is still valid but it might be handy: https://www.freebsd.org/doc/en/articles/filtering-bridges/


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