So far, we have discovered various ways of integrating the IN application logic to the WebRTC call flow(IMSSF), making a call to the GSM client from the WebRTC client (SGW, MGW) and delivering an SIP message from the WebRTC client to a GSM phone (SMS gateway).

The implementations of these are meant to prove the feasibility of the proposal and not necessarily signify how the production environment must be. In order to construct a stable, scalable, and resilient communication system, one must ensure that the signal is well connected to all nodes via their interfaces and that the media is flowing smoothly. Interoperability issues usually arise on the border of these networks where issues such as protocol conversion and media codec conversion take place. The placement of appropriate gateways helps prevent these errors and smoothens out the differences.

The next chapter deals with WebRTC interconnectivity with old telephone systems such as PSTN. This shall be carried out through interoperable...