Multi-location Multicast

We have a client with 150 phones across 5 physical locations. They want a “page all” button, that when pressed, puts every phone, in each of the 5 locations, off-hook and plays the page audio. We do this with multicast when it is a single location on a single subnet. But, this is across 5 physical locations, each location behind a separate internet connected firewall/router.

It looks like the Algo 8301 will accept a SIP call and then transmit a multicast page. The thought is that we could put an Algo at each location, put each Algo’s SIP extension as a Page Group member, then when somebody dials the Page Group number, each Algo receives a call and in turn creates a multicast stream that each phone plays.

Is this the best way to achieve 150 phone paging, across 5 locations, with only 5 RTP streams and not 150 streams? Is Algo the most reasonable cost device to do this ($350 each Algo 8301)?

Thanks in advance

multicast requires all devices to be on the same LAN

Each Algo device is on its local LAN. It contains a SIP registration and outputs a Multi-cast stream. That means a separate stream from a local Algo devices at each location.

ahhh that is actually pretty cool. I stand corrected

I would look at multicat (sic.) at all endpoints , it probably could do the same thing (multicast(LAN)->unicast(WAN)->(LAN)multicast X5 )


This recipe seems to work for me at first glance, using a couple of polycoms on different networks. can’t say what the far end phone sounded like but the traffic seems kosher.

On the pbx run for each satellite office

multicat -u @ ip.of.office1.multicathost:5005 &
multicat -u @ ip.of.office2.multicathost:5005 &

where your.officeN.handy.machine s are convenient hosts (as little as a raspberry pi should do) each running serving a multicast on their LAN

multicat -u @:5005

don’t forget your firewall rules :wink:

Multicast is meant to be routed! It’s the whole point.

multicast relay …

the Snom PA1has that feature and iirc some cyberdata units as well

routing may be possible but i cant get my head around it with your network description

i think you’re on a good path using a relay device

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