Managing Feature Interactions between Distributed SIP Call Control Services

Abstract

The Session Initiation Protocol (SIP) is widely used as a call control protocol for Voice over IP (VoIP), and indeed commercial implementations are readily available off-the-shelf. SIP supports flexible service provisioning not only through third parties, but also end-users. Laboratory experience shows that as these services are interworking they are subject to the feature interaction problem. Feature interactions may considerably delay service deployment and hence are a threat to rapid service provisioning. This paper investigates the feature interaction problem in SIP-based services and investigates the application of a pragmatic approach. This runtime approach does not require any detailed information about the services and hence can be applied in a competitive market. Furthermore, the technique is particularly strong in handling interactions between distributed services – a key characteristic of SIP-based services. Moreover, the approach is fully distributed without any centralised components, and includes detection and resolution of feature interactions.