The Session Initiation Protocol (SIP) is designed for telephony applications, supporting one-to-one communications only. SIP does not scale well for group-oriented communications, while it requires a central controlling node, and cannot use IP multicast for efficient distribution of speech and signalling packets. In addition, SIP does not support PTT operations.

Interoperability with SIP is an important consideration for the development of the ODINI ecosystem, however. By means of a SIP telephony server, user of telephone sets can access radio subscribers and vice versa, supporting both individual and group calls through ODINI.