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Enable Push-to-Talk

This guide enables group calls with floor control with Ella IMS's built-in Mission Critical Push To Talk (MCPTT) server. The examples use 10.6.0.5 as Ella IMS's SIP address.

Prerequisites

1. Enable the MCPTT server

In ims.yaml, set the address phones reach the MCPTT media on, and restart Ella IMS:

mcptt:
  media:
    address: 10.6.0.5

2. Configure Ella Core

In the Ella Core UI:

  • Networking → Data Networks → Create: mcx, with an IP pool and IMS on.
  • Profiles → Create: an MC profile, e.g. mcptt. On it, Add Policy: a name, data network mcx, 5QI/QCI 69, ARP 3, May pre-empt, Not pre-emptable.
  • On the MC profile, also add the policies the users had on their previous profile, e.g. internet and ims.
  • Operator → IMS → Add Application Server: click Fill for Ella IMS MCPTT, then Add.
  • Profiles → the MC profile → edit IMS Filter Criteria: Add from preset the MCPTT preset, then Save.
  • Subscribers: put each user on the MC profile, with an MSISDN.

3. Route the MC traffic

On the Ella IMS host, route the mcx IP pool through Ella Core's N6 address, e.g.:

sudo ip route add 10.47.0.0/16 via 10.6.0.2 mtu lock 1400

4. Add the users

In the Ella IMS UI, go to Push-to-Talk → Users. For each person, click Add User and enter:

  • MCPTT ID: e.g. alice.
  • IMS Identities: the subscriber's MSISDN, e.g. 15550000001.

5. Add a group

Go to Push-to-Talk → Groups, click Add Group, and enter a group ID, e.g. fire, and its members.

6. Set up the phones

On each phone:

  • Set the APN to mcx.
  • In the app's settings, set the user's MCPTT ID as Ella IMS shows it, e.g. [email protected], and groups.

7. Make a group call

Start a group call from one phone. The other members' phones should ring, and Push-to-Talk → Calls should show the call.