Defining Signal K server Service Discovery/DNS-DS?

[pekka leppanen]

I have a basic (including 'sudo apt install libnss-mdns avahi-utils libavahi-compat-libdnssd-dev') Signal K server running on RPi, with working NMEA 0183 and 2k data connections. 

I can listen its "Convert Signal to NMEA0183" output with my app at  given TCP address and the default port.

I'd like to enhance my app to connect via Bonjour/DNS-DS, but cannot figure out how to configure SK server's '_signalk-tcp._tcp' and start running the DNS-SD. ' The 'dns-sd -B _signalk-tcp._tcp' shows no advertisements from the RPi.

The 'https://signalk.org/specification/1.5.0/doc/connection.html' is quite detailed on what needs to be in place, but not how to do this?

Any help is appreciated,

pekka