One of our customers reported some severe issues after we placed a speed dial button on their attendant consoles for their multicast paging group. Whenever they received an incoming call or placed an outgoing call, both streams of audio would play through the multicast group. Removing the speed dial button resolved the issue, however they are still requesting that particular feature.
I've reproduced the issue in a lab setting, using two 525G2s and one 504G, all with attendant consoles. The paging group is using 22.214.171.124, port 10000, number 1150 and the speed dial button can be placed on the phone or on the attendant console. I previously used 126.96.36.199, port 60000, but tried a combination of port/address changes that were inneffective. Initially I was using firmware version 7.4.8, but then upgraded to 7.4.9a, then to 7.4.9c, but this did not alleviate the issue.
As it stands, the issue will NOT present itself until the paging speed dial button is first used after either a reboot or a resync. The issue does not occur if the paging group is dialed directly and it only seems to happen on the SPA-525G2. The 504G will not activate multicast under these circumstances.
After the button is used, any incoming call will cause the 525s to multicast packets, even if the call is just ringing and not being answered. Conversely, simply engaging the line by picking up the handset or pressing the speakerphone button will activate multicast.
Has anyone come across this issue previously? I've searched the forum and Google, but haven't found any information thus far.