One of the interesting features of the SightCall platform is the fact that one User may be signaled on multiple “extensions.” This feature is nice to use in collaboration applications. Suppose one of your Users is logged on to the application on a web browser and a mobile device. Your application can “ring” the User on all of his or her devices simultaneously. The first device to pick-up the call receives the call, and the calls to the other devices are canceled.
For instance, a User named “Alice” may want to call User “Bob.” Bob is logged in twice – once on his laptop and once on his mobile device. Both devices will ring, and Bob can answer on the device most convenient for him.
This feature is related to the way in which applications built with SightCall connect their Users to our cloud. When a User logs into an application you have built using SightCall, your application verifies the Identity of the User. In most web-applications this is done with a username and password, or by using third-party authentication with an identity from Facebook or Twitter or Github. Once your application has verified the identity of the user, it begins a process called “SightCall authentication.” Authentication links the User’s current device to their Identity.
Authentication can occur with the same Identity on multiple devices. As a result, one Identity can be the SightCall name for multiple extensions.
In TelCo-speak, each time a device becomes an endpoint on the SightCall platform it is “provisioned.” In the old days, provisioning linked a fixed identifier (like a phone number) to a hardware device. In the world of web-services and software telephony, Identities are tied to applications and endpoints are software applications, not a piece of hardware. The mapping of an Identity to an endpoint is transient.
With SightCall, provisioning is an inexpensive and potentially short-lived operation. We optimize the process so that authentication, provisioning, de-provisioning and logging-out can work easily with the way that people start up and close Single-Page Web Apps.
WebRTC by itself does not define a signaling policy or mechanism. SightCall’s signaling mechanism is robust and flexible. The feature described here is just one way we help connect your apps the way you want.