Hi,

I have a problem with sending UDP multicast packets from phone(wifi) to laptop(wifi). In other way when I send it from laptop to phone, everything works. The code of multicast listener and sender are good, because I get it from external website and it work on wifi based on Thomson router. I notice, that my error exist in local network based on siemens gigaset 504ag router. It is a way to fix this bug?

Run Wireshark on the laptop.
Do the packets from the phone show up?
If not, then the problem is with a multicast bug in the phone, or perhaps the router/switch)
(Is the router/switch billed as supporting multicast groups?)

If that's the problem, then broadcast might be a suitable work-around when you only care about the local network.
(And multicast doesn't actually work/scale across the general internet anyway, so you'll need a unicast solution for that.)

Out of curiosity, since you're trying out multicast now, did you get your broadcast issues worked out over the past two weeks?

Hopefully you got all those resolved and are now looking into multicast as a theoretically better solution at scale --- unfortunately multicast doesn't work in the real world. It is rarely supported on commodity hardware and it doesn't work generally on the Internet at large.

As suggested by your previous thread, you've likely got a network switch or some firewall that is blocking broadcast, so it likely is also blocking multicast.

I worked for a company dealing with industrial wifi usage (lots of fun) and with what we experienced it is (is it) possible (?) that the phone's hardware and or software isnt supporting (user) Multicast features ???

Any reason why it is needed for that product (to have it included in drivers/chipset or even to be intentionally chopped out of the software)?