VVoIP session signaling must be encrypted to provide end-to-end interoperable confidentiality and integrity.

Because vendors did not have interoperability, lacked end-to-end encryption, and did not provide assured service in support of Command and Control (C2) communications, VVoIP traffic originally was restricted to the local enclave. The DSN PMO, DISA Engineering, and Real Time Services (RTS) working group have been working to define network and system requirements to overcome the inherent obstacles in pursuit of a DISN wide interoperable assured service VVoIP or Voice Services network.

VVoIP uses signaling protocols to set up and manage the communications session and the media transfer protocols carrying the communications. Both signaling and media protocols can be compromised when transmitted without encryption. To provide the assured service pre-emption and priority capabilities required for C2 telephone communications, DISA developed an extension to the SIP protocol called Assured Service SIP or AS-SIP. The common means of providing confidentiality and integrity for SIP signaling as well as providing session authentication is to encrypt it using TLS. The encryption algorithm, key strength, and key management processes are denied in the current version of the DoD Unified Capabilities Requirements (UCR) document available from the DISA voice Services PMO.