VoIP-PSTN interoperability by asterisk and SS7 signalling

Abstract

PSTN, the world's circuit-switched network, has employed Signalling System #7 as its protocol suite for international and national interconnection during past decades. VoIP networks however have developed different signalling protocols suitable for IP environment. Gateways interconnecting VoIP and PSTN networks are usually proprietary and expensive solutions. Today an open source software can perform this function. As an example we have decided to test Asterisk PBX and two open source implementations of SS7, the SS7 channel driver and SS7 library. We have tested these solutions for interconnection to PSTN and run various tests to verify the implementation functionality. © 2007 International Federation for Information Processing.