ITU-T Study Group 11 - Signalling requirements, protocols and test specifications
Study Group 11 is the 'signalling' group within ITU-T. It produces ITU-T Recommendations that define how telephone calls and other calls such as data calls are handled in the network. Previously, this was predominantly in the public switched telephone network (PSTN) and Integrated Services Digital Networks (ISDN). Now, as operators look to align this 'circuit switched' based environment with the rapidly emerging Internet technologies, SG11's work is shifting towards Internet protocol (IP) based networks or next generation networks (NGN).
Study Group 11 is home to Signaling System 7 (SS7), without which telecom systems worldwide would not interoperate. All telephone switching systems need signalling. It provides the means for monitoring the status of a line to see if it is busy or idle, alerts that indicate the arrival of a call, and the addressing system that routes calls. Before SS7's implementation, not all nations were party to the standards agreements enabling international telephone calls. SS7's implementation thus paved the way for the efficient operation of international telecommunication networks.
Another key achievement of this group was the development of a set of ITU-T Recommendations for intelligent network (IN) and bearer independent call control (BICC). Published in 2001, and an important step towards NGN, these standards eased the migration of PSTN services and their many supplementary services to IP based network architectures. In particular, BICC was adopted by the 3GPP for application to the circuit switched core networks.
Further, SG 11 has developed a set of protocol procedures and applications to support resource admission control on the following IETF protocols: diameter, simple network management protocol (SNMP) and common open policy service (COPS).
Additional work includes signalling flows and protocols to support IPTV services. Current work includes the development of signalling architecture and signalling flows to support mobility.
SG 11 is also responsible for Testing. Work currently focuses on global interoperability testing; covering technical means, services, QoS and testing parameters. Activities encompass: establishing benchmark testing procedures, investigating the testing of ubiquitous sensor networks (USN) and network aspects of identification systems (NID), and studies relating to the monitoring of modern networks. SG 11 also develops handbooks in this field (e.g. handbook on "testing" and handbook on "network performance testing and control for guarantee required QoS for NGN services").
SG 11 is the Lead SG on testing specifications. In the future, SG 11’s testing work will be expanded to incorporate emerging technologies such as the Internet of Things (IoT), Vehicular Ad-hoc Network (VANET), Distributed Service Network (DSN) and Home Networking (HN).