Multicast Stops Working until Phone Rebooted

[Blake1]

(07-06-2022 01:47 AM)complex1 Wrote:  

(07-05-2022 11:18 PM)Blake1 Wrote:  I haven't found a solution yet, I am looking at IGMP on switches causing the issue potentially, but most of my customers don't know how to manage their switches to confirm if any IGMP snooping/filtering is in place. I seem to only be having this issue on the T5X series phones, but I've been unable to recreate.

Hi,

Have you ever thought about submitting a support ticket to the Yealink helpdesk?
https://ticket.yealink.com/

I haven't opened a ticket as I was trying to understand the bug some more, and I may have figured it out.

Just did some packet captures on a customer net where we're having this issue. The customer is using all T53 and T53W phones. We did some multicast testing and found that their switch will only relay multicast packets to ports that join the IGMP group for the MC address first, and it looks like the T5X series phones are NOT joining the IGMP group even when listening is configured.

I just tested in my office by enabling IGMP filtering on my switch (it was off by default), and now when I send an MC page all the T4X phones get the page, but none of the T5X phones do! So I have enough ammo to open a ticket now as it looks like the issue is the IGMP join on the T5X series phones is not working as expected.