Hi All,
I have RTFM'd , I have searched the forum (admittedly not to exhaustion)
so here goes with a question.
An "Internet neighbour" and I wish to shared UDP
AIS data between ourselves
in order to improve our own non-commercial
AIS coverage as well as offering our data to a number of online services , such as shiplotter, marinetraffic etc.
I cannot run Shipplotter on my PC as I have Planeplotter and several other professional apps that prevent co-exstence with Shipplotter. I therefore use
OpenCPN and accept that I only receive local area data (which is all I really want)
our "sharing goals" are simple enough:
* My Neighbour would like to see traffic from
Newport locally in Shipplotter (He can see the majority of ships, but not those in
parts of
Newport Docks and Portbury)
* I would like to see Cardiff locally (I have blackspots created by two islands in the river Severn and a local obstacle)
* I would like my neighbour to be able to share my Newport data with Shipplotter and Shipfinder (I expect no
privilege from either site in return)
* I do not want to see global content coming in from shipplotter on my
OpenCPN PC (nor should I as I am not a direct contributor)
* We both would like to continue contributing to marinetraffic.com but should either of us go offline, we would like the other's feed to continue
So we set up a test harness (as per the attachment)
And whilst we could indeed see each others data, it created an AIS feedback loop between our respective sites resulting in 10s of thousands of messages a minute. We have therefore suspended testing.
I have read about input and output filters in OpenCPN and freely admit that the AIS payload is not my expertise (im more a firewalls, VoIP, SOAP , SQL, routers, and 3GPP protocols kind of person as my day job) But is there a way to filter UDP output traffic based upon connection source please ? I.e. can I say only traffic that came from my COM1 can go out over the UDP connection to my neighbour ?
I have set my own com 1 priority to 9, my primary output (marinetraffic) to to 8 and forwarding to my friends PC as everything between 0-7 which has made no difference to the message storm. I have asked a similar question to the developer of Shipplotter by
email. Is there some way to "Tag" my outbound traffic with talker ID then remove it when it comes back around the loop with an input filter to prevent it continually going around ?
Grateful for any assistance you may be able to offer
Many thanks in advance
Regards
BB