You can configure the devices that are on the same LAN to send a receive paging sessions using device overrides. This feature requires that the SIP device supports multicast paging and does not involve any switch functionality other than the provisioning of overrides onto devices from the SkySwitch provisioning server.
In most hosted PBX deployments, it is not feasible to page multiple devices from the switch because each device paged requires a separate call path. As a result, if a page is sent to 10 devices, it will require 11 call paths (one for the pager, and one for each of the pagees). This is not optimal because it could easily saturate the Internet bandwidth and degrade the voice quality for other callers. The solution is to use multicast paging where the devices communicate with each other over the LAN only (and therefore no call paths are established to the switch).
Multicast will work across different phone brands in most cases, but certain phones define a codec for Multicast. You must also ensure the codec matches across brands. Polycom uses a proprietary Multicast protocol and will only work with products designed to use this protocol.

Multicast Paging on Polycom Phones

The following override will create two page groups; page group 1 is "All Page" and page group 2 is "Sales". Devices that include these override settings will be able to send page to these two groups.

ptt.pageMode.enable="1"
ptt.pageMode.group.1.label="All Page"
ptt.pageMode.group.2.label="Sales"
feature.nonVolatileRingerVolume.enabled="1"
np.normal.ringing.toneVolume.chassis="1000"
np.normal.alert.messageWaiting.tonePattern="silent"

In order to receive pages, individual devices must 'subscribe' to one or more page groups. The following override will allow devices to subscribe to the Sales group (group 2).

ptt.pageMode.group.2.subscribed="1"

The following override will allow devices to subscribe to both the Page All group (group 1) and the Sales group (group 2).

ptt.pageMode.group.1.subscribed="1"
ptt.pageMode.group.2.subscribed="1"
The default multicast IP address used by Polycom phones is 224.0.1.116. The default multicast port is 5001. Default values may be changed with the following overrides:
ptt.address="224.0.1.117"
ptt.port="5003"

For more information on multicast paging with Polycom devices, see this guide.

Multicast Paging on Yealink Phones

The following override consists of two parts:

  1. The 'listen' override lines will allow devices with this setting to receive pages from other devices.
  2. The 'linekey' override lines will allow devices with this setting to send pages to other devices.
#LISTENING INSTRUCTIONS - ADD TO ALL PHONES or DOMAIN OVERRIDE ?
multicast.listen_address.1.ip_address="224.5.6.20:10008"
multicast.listen_address.1.label="page all"
#ADD A BUTTON TO THE PHONE TO USE THIS FUNCTION -
linekey.2.type="24"
linekey.2.value="224.5.6.20:10008"
linekey.2.label="Page All"
#THIS OVERRIDE BELOW WILL NOT ALLOW THE CURRENT CALLER TO BE INTERRUPTED WHILE ON THE PHONE BY AN INCOMING PAGE
multicast.receive_priority.priority="0"



Multicast Paging on Grandstream Phones

Please refer to this manufacturer document:Multicast Paging User Guide

Multicast Paging on Vtech VSP/VCS Phones

You must set up to 10 Multicast Page Zones. Here is a zone 1 example.

page_zone.1.name="Multicast"
page_zone.1.multicast_address="224.0.1.116"
page_zone.1.multicast_port="5001"
page_zone.1.accept_incoming_page="1"

Set Multicast Page Zone to a PFK. The following override would set the second PFK to use Multicast Zone '1'.

pfk.2.feature="multicast page"
pfk.2.multicast_zone="1"

Multicast Paging on Cisco SPA Phones

The 'num' is the number to dial to start a multicast page.

pggrp="224.0.1.116:5001;name=All;num=800;listen=yes;"

Snom PA1 as Multicast Listener

mc_address1="224.0.1.116:5001"

Snom PA1 as Multicast Relay

The Snom PA1 can be configured to take Unicast RTP and relay to Multicast. Meaning you can setup the Snom PA1 as an extension, then call that extension, the Snom PA1 will broadcast that media to its own output and to a configured Multicast Address.

multicast_relay_address1="224.0.1.116:5001"
The Snom PA1 Cannot be setup as both a listener and a Relay at the same time.