Main Site Documentation

Multicast on WiFi


#1

Dear all,
sometimes ago a colleague of mine asked about multicast support on WiFi.

Support Admin answered:
“I would say multicast is not working on WiFi as of now but we will look into this in near future. No grantees on when and what will be supported though.”

I have been looking trough release notes and I did not find any news.
Is there any news about that?

Thanks!

Following the original discussion:


r13r12:
Hi,

Im using a couple of ChipworkX with a program exploiting DPWS features. Ive found that I was unable to perform a complete DPWS discovery after switching the program from Ethernet to WiFi connection (i.e I have a working solution that uses eth and a not-working solution which is the same but adding a WiFi connection).

Investigating more it seems that the ChipworkX is not receiving multicast packets, thus blocking the discovery algorithm. I put up a little test using 2 boards with wifi expansion, one that runs the complete DPWS discovery and another one with a piece of code from DPWS stack: set a socket , join the multicast group 239.255.255.250 and print everything that comes from the UDP port 3702 (DPWS discovery port).
During the test this board didnt print anything despite having proper packets for ip add 239.255.255.250 UDP port 3702 sent through air by the first board (as Wireshark running on a laptop can tell). I checked this test program using Ethernet as default connection, and in this case I was able to have the soap messages printed (the board was attached to one of the four eth ports of the access point).

I was wondering if something went wrong calling the MF API SetSocketOption and the membership was not correctly added to the ZG2100 module (anyway I didnt receive a socketexception for this):

// Join Multicast Group
byte[] multicastOpt = new byte[] { 239, 255, 255, 250, // WsDiscovery Multicast Address: 239.255.255.250
0, 0, 0, 0 }; // IPAddress.Any: 0.0.0.0
m_udpReceiveClient.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, multicastOpt);

Am I missing something in order to enable the WiFi module receiving multicast packets?

My configuration:
MF 4.0
ChipworkX firmware 4.0.3.1,
ZeroG ZG2100 wifi expansion (example code from GHI documentation that enables WiFi Interface)
Linksys AP

SupportAdmin
There is a good chance the ZeroG WiFi modules do not support multicast and if that is the case then there is nothing we can do on our end.

r13r12
Thanks for your quick reply.
So long I didn’t found any specific information about ZG2100 and multicast support, nothing that states clearly if multicast is supported or not.
Could you please check and confirm that using multicast with ZG2100 is not an option? There is another wifi module suggested by GHI that support multicast?

SupportAdmin
I would say multicast is not working on WiFi as of now but we will look into this in near future. No grantees on when and what will be supported though.


#2

We have not test multicast with wifi.

Would you like to help us? Do you have a simple application code that might help us test multicast?


#3

We performed tests on ChipworkX firmware 4.0.3.1 and it doesn’t work.

Did you perform any change to WiFi since that?


#4

No changes have been done on the WiFi side. There are some internal future plans though. If this is a must feature then please contact GHI directly.