3.12.1 ONNET and OFFNET

Calls are divided into two types:

• ONNET – within the network, in the OTT service it means calls made over internet, among the users of the same service, this type of calls is free
• OFFNET – outside the network, in the case of OTT it will be calls to voice termination carriers which terminate calls to PSTN (landline or mobile) networks

The RCS clients can recognize when the call is ONNET or OFFNET as the softphone’s UI is designed in such a way that a user can decide whether he wants to connect to another RCS user directly over internet or to call the user’s phone number over PSTN network.

If a contact is not RCS user there are only “paid call” and “paid SMS” icons available, allowing only for OFFNET communication.

Calls to PSTN are realized through the gateways (carriers) defined in the Destinations menu in VSM. More on configuring the routing and gateways you can find in voipswitch documentation in a dedicated chapter TODO link.

The RCS client uses two separate SIP accounts with different configuration for each of the types. It may also use different SIP login and password pairs which can be necessary in some scenarios, for example when the OFFNET traffic requires 3^rd party billing (read more in the Integration chapter). In general the credentials are the same. The difference is in their configuration.

• ONNET configuration – calls are made with ICE, SRTP encryption, audio codecs OPUS, video codec vp8
• OFFNET configuration – ICE is disabled, no encryption, audio codecs: g729, g711 (other can be added on request)

The difference in offered codecs is because at the moment OPUS is not supported by the termination carriers. The most widespread codec is still g729. The set of codecs can be narrowed on the gateway definition in the VSM.