What is IMS call flow?

The calling IMS subscriber is currently roaming outside the home network. The called user is registered in the home network. The caller and the called user require resource reservation before the call can be setup.

How do I check my IMS status?

Enter dialer code ##4636## and find that VoLTE, carrier video calling, and wifi calling toggles are grayed out and cannot be toggled. Check IMS information with 3 dots in top right corner and see “IMS not registered” and all options below (VoLTE, video calling, etc.)

What are the key protocols used in IMS?

From a UE perspective IMS defines a set of protocols to be used: Session Initiation Protocol (SIP), SigComp, Real-time Transport Protocol (RTP), RTP Control Protocol (RTCP) and IP Security. Other protocol such as Diameter is involved in the IMS core but is transparent to the User Equipment.

Is flow GSM or CDMA?

FLOW uses the GSM standard for 2G which is accessible on 850 and 1900 MHz. It provides data connectivity exclusively using GPRS and EDGE. All FLOW markets have GSM coverage.

What is the typical IMS SIP registration call flow?

Here is a typical IMS SIP registration call flow. The IMS client attempts to register by sending a REGISTER request to the P-CSCF. The P-CSCF forwards the REGISTER request to the I-CSCF. The I-CSCF polls the HSS for data used to decide which S-CSCF should manage the REGISTER request.

How does an IMS terminal access the home IMS?

An IMS terminal accesses the home IMS via a visited IMS. Unauthenticated registration followed by authenticated registration is covered here. Call flow for an IMS subscriber to another IMS subscriber is covered here.

What is the IMS to PSTN (ISUP) interworking call flow?

IMS to PSTN (ISUP) Interworking Call Flow. This call flow describes the call setup from an IMS subscriber to ISUP PSTN termination. The call is routed via the BGCF (Border Gateway Control Function) to the MGCF (Media Gateway Control Function).

Where is the calling IMS subscriber currently roaming?