Problem with Multicast Paging -- paging phone also answers its own page


I have a client with an office using a few dozen GXP2130 phones plus a single GXP2140 phone. I set up multicast paging as per the document:

But it turns out I can’t have the initiating phone also listen to the same multicast address. When I do, it answers its own outbound page as if it were a concurrent inbound page. Ignoring the problem of the extra feedback caused with the speaker and earpieces being in such close proximity, for now. And then when done paging, I have to hang up twice: once for the answered-on-speakerphone call, and once again for the outbound page.

What this means is that we can’t set up ALL the phones to universally be both senders and recipients of multicast pages.

I see that a similar problem was posted back in 2014, with only a promised “future” fix. Is there at least a workaround? Something besides setting up multiple paging groups, because there’s more phones than available groups (a limit of 10).


Using PBX for that ?


As I’d said, I followed the document.

The Multicast Paging feature on the GXP21XX phones works independently of any PBX, it’s all directly phone-to-phone.


The phones do indeed support native multi-cast. However:

  1. The PBX does as well and it is a far more elegant solution.
  2. Are you registering more than 1 key to the same account?
  3. More than one line presence to the same account?
  4. Call waiting?


Multicast is broadcast it is not selective. Your phone listen or not on that port. GS do not have any extra checking who transmit it.
PBX on other side can control where to sent and it not using broadcast but normal sip invite communication (unless set as broadcast too).


Elegant or not, the PBX is not on the same LAN as the phones themselves.


I find it absurd that this exact problem was described in these same forums in 2014, and that Grandstream themselves said they were working on a solution in an upcoming firmware release.


Sorry, but it was not stated/known that the phones were on a different subnet or connected to a UCM. It was merely an option for consideration.

The only thing I can suggest is to submit a feature request to support as I look at the firmware release notes and saw nothing that indicated a change.


For us, this issue is resolved after initial multicast configuration then rebooting the phone.