fgms 0.13.5
FlightGear MultiPlayer Server

The FlightGear Project (fg)

FG Mailing List

Most developer cummunications is though the mailing list and IRC

On this page


This is an example command line used to launch a sim

> fgms --callsign=test1 --multiplay=out,4,mpserver14.flightgear.org,5000 --multiplay=in,4,localhost,5000

The important command line vars for us in fgms land are:

There must be no spaces eg
--multiplay=in,4, my.server.address ,5000
oops ^ oops2 ^

The –multiplay option is broken down as follows

  • direction
    • out for sending to an mpserver
    • in for recieving from a connection
  • freq_hz
    • the number of times a second udp packets are sent
    • a high number eg +10 will be bombarding the network
    • around 4 frames a second is cool enough
    • even lower eg 2 frames a second
  • host
    • for out - this needs to be the server address eg mpserverNN.flightgear.org
    • for in - this needs to be your host name or ip eg localhost
  • port
    • by default this is 5000
Users were previously encouraged to use 10 hz. This consumes a lot of bandwidth. This number comes from the time when fgfs was not able to 'emulate' a remote aircraft while no data is received. The first multiplayer versions just updated a remote aircraft's position on data reception and the aircraft stayed where it was until the next position arrived. Since then a lot of things have changed, but we never tried to reduce the number of packets. Its recommended that 2 to 4 pps are enough.
See also
fgfs Command line options the the FlightGear wiki

Info for fgms developers

Bits of the multiplayer code from flightgear is copied as needed

Of interest also is the list of "properties" that are sent. Although these are simply relayed.