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Integrate with an Application Server

This guide connects an Application Server (AS), such as voicemail or conferencing, to Ella IMS. The examples use 10.80.0.30 as the AS's address and 10.6.0.5 as Ella IMS's SIP address.

Prerequisites

  • HSS: an HSS that provisions initial Filter Criteria (iFCs).

1. Trust the AS

In ims.yaml, add the AS's address to the trusted networks, optionally set how long the AS has to answer, and restart Ella IMS:

sip:
  trusted_networks: [10.80.0.30/32]
scscf:
  as_timeout: 4s

2. Add iFCs in the HSS

In the HSS, add iFCs to the subscribers' service profiles, with the AS's SIP URI as the server name, e.g. sip:10.80.0.30:5060:

  • For third-party registration, add a trigger point on method REGISTER. Set Include Register Request and Include Register Response if the AS needs them.
  • For originating or terminating services, add a trigger point on the session case, plus the method, header or Request-URI to match.
  • Set the default handling to SESSION_CONTINUED to go on without the AS, or to SESSION_TERMINATED to fail the call, or deregister the user on REGISTER.

3. Add the AS's PSIs

If the AS serves its own URIs, such as a conference factory:

  • Add its PSIs to the HSS, distinct or wildcarded, with their iFCs or the AS as their server name.
  • If the server name is a host name, make it resolve to the AS, with a DNS A or SRV record.

4. Configure the AS

On the AS:

  • Trust Ella IMS's SIP address, 10.6.0.5.
  • Send requests to a user to the I-CSCF, port 5070.
  • Send requests on behalf of a user or a PSI to the S-CSCF, port 5080, with orig in the Route header, Route: <sip:10.6.0.5:5080;lr;orig>, and the user in P-Served-User or P-Asserted-Identity.

5. Verify

Register a phone. The AS should receive a third-party REGISTER, or the first request that matches its iFCs.