It is possible to reduce the delay before Cisco Paging System (Informacast basic paging) start streaming to the phone. We are getting two seconds delay right now.
Did you ever figure out the issue? Our CUCM version is 11.5
Sometimes there is no audio delay, sometimes there is a 10+ second audio delay, and sometimes there is no audio at all. The phones also don't always get the signal from informacast to join the multicast group and start receiving the led blink and/or audio. It's very inconsistent.
Having same issues. Have opened a TAC case and got packet captures for them but they are not finding an issue but there is definitely something causing a random delay in the multicast. Please let me know if your were able to find root cause of this.