Calls made by Predictive dialers (Robo-calls) utilize a dial software to activate SIP trucking to enter the PSTN (Public Switched telephone network). Identification and black-holing of this traffic would remove (over time/post identification) the access given to the predictive dialer. The solution would involve utilizing the numeric/feature codes identifier on the PSTN such as #99 to identify a received call as the type to be blocked from the network. Activating the PSTN to identify the source of the call e.g.ANI/ Trunk group-the call would be added to the black hole list removing subsequent calls from the network. If access to the transport IP network is an option, the SIP trunk group could be identified and black-holed further up-stream to block the traffic from entering the PSTN. In a diagram depicted in the body of the summary of the proposal (see attached proposal file) prior to reaching the customer (regular phone) the opportunity for screening exists : Core Internet gateways, PSTN gateways and through gateways prior to accessing the mobile network. Utilizing the following network design options, traffic identified though a pre-determined method (such as IP trunking info, ANI/telephone number or other call initiation data) would be sent to a null interface ending the attempt to reach a consumer through the use of automated dialing.
Implementation of this design may be enhanced by hardware or software solutions designed to actively identify offending telephone numbers or trunk groups. At core gateways to transport IP networks (including off-shore) black hole lists would remove identified offenders prior to entering the long–haul network-removing the nuisance and IP traffic load. Evaluation of inbound SIP header information coupled with access points availability will lead to the screening criteria and black hole list applications.