A SPIT Avoidance Workflow for SIP-Provider

Voice-over-IP (VoIP) replaces traditional telephony network infrastructures in growing numbers. Along with this infrastructure change, SPam over Internet Telephony (SPIT) is likely to spread massively, similar to spam in e-mail infrastructures. Thus, it is necessary to develop appropriate countermeasures. Since, the request for a call, usually indicated by the ringing of the phone, might already be a disturbance or annoyance of the called party, traditional content-based preventive and defensive measures, used to avoid e-mail spam, are not applicable anymore. This paper presents a new SPIT Avoidance Workflow for the detection and prevention of unsolicited calls and its implementation.