As we know that SIP IMS is a good way to implement a unifying technology (refer to the following diagram) between the legacy circuit-switched and the IP-based packet-switched networks, it is clear that the best approach to integrate WebRTC to the IN telecom network is via SIP IMS; this is illustrated in the following diagram:

In the previous section, we saw the process of using the mobile packet-switched network to interact with the WebRTC client. This section describes the process of using the circuit-switched voice network to call a WebRTC client. To achieve this, there must be a point of translation between the voice network of the mobile and the IP network of IMS. This is often referred to as the GSM Gateway.

The difference between Circuit-Switching and Packet-Switching technologies is described in the following table: