Multicast UDP will enable communication with multiple ESP's on the network using 1 single Multicast IP address. This would facilitate discovering ESP's on your network, or other solutions where multiple ESP's should react on a packet from single client.
The sketch seems to work OK with the application "Packet Sender" on Mac OSX as counterpart (available for OSX, Windows, Linux, etc. at packetsender.com):
- The sketch reacts on the selected Multicast IP address and port. Packets sent to the ESP are recognized.
- The sketch sends a confirmation UDP packet back to the sender, and this packet is received in Packetsender.
I did not try loading the same sketch on multiple ESP's, yet.
IGGR informed me that applications like mnc en multicast should also work. Have not tried these.
NOTE : I started with using netcat/nc on Mac OSX but apparently this does not support Multicast. The Multicast packets were received by the ESP OK, but the confirmation message sent back did not arrive.
Below you will find:
- Screen dump, left = Serial Monitor ESP, right is Packetsender on Mac as UDP client
- the sketch