Wiresharking Radar Gofree Navionics Android UDP Mulitcast Sleuthing

[rgleason]

Some of you are wizards at connections & radar, here is information about connecting things and sleuthing and a pretty good blog for Marine Electronics by stripydog. The last post talks directly about Radar over wifi. (I think we will find it is best to keep radar & data on separate wifi channels, whatever the protocols involved.)

It might be helpful sometime, or get people thinking...
Did not know where to put this.

Gofree, Navionics,
Navionics SonarChart™ Live on Android
Water and Electrickery: Navionics SonarChartâ„¢ Live on Android

Of interest to me was the use by Navionics Charts of cell phone data bandwidth.. another reason for OpenCPN Android!

Marine Data Transports revisited.
Water and Electrickery: Marine Data Transports Re-visited

Meantime though, 96% packet loss clearly makes broadcast/multicast over wifi non-viable. The alternatives?

• Use TCP. Easy. Well supported
• Use UDP unicast. Client addresses must be known in advance or some (currently non-existent) subscribe/publish protocol needs to be developed for marine data
• Use an access point which implements UDP multicast over 802.11 unicast (as discussed in the RADAR post). Support for this is rare, as is support for NMEA-0183 data over multicast.

For most people the solution for now would seem to be to use TCP for delivering marine data over wireless networks.

Radar over Wifi not always a pretty picture
Water and Electrickery: RADAR over wifi: Not always a pretty picture

OpenCPN plugins support overlay of imaging from some Garmin and Navico RADAR units. Unfortunately some users attempting to use these plugins over wireless networks on their boats have encountered issues. Not only does it not work very well, it can make the whole wireless network unusable.

Signal K - iKommunicate
http://stripydog.blogspot.com/2015/1...ed-part-2.html
http://ikommunicate.com/

Getting pretty complex now.