PDF of this tutorialWork on CS–2 in the ITU–T study group was started in 1994 and was completed in 1997. Because of the large size of the CS–2 recommendations, they are being scheduled for publication in late 1998. CS–2 includes many new capabilities over CS–1. There are more interfaces between the functional entities, along with some additional functional entities. Figure 5 shows the functional relationships for CS–2.
Figure 5. IN Functions and Functional Relationships for CS–2 (from Q.1221)
As can be seen in Figure 5, additional functional entities are defined for CS–2. Additional relationships are also defined between the existing functional entities. CS–2 allows for more advanced and complex services than those offered with CS–1. CS–2 allows for greater integration and access to information in the operator's network and across operators' networks. This is particularly evident in the relationships between SCFs and SDFs. The multiple SCFs and SDFs can reside within an operator's network, or can be in different operators' networks.
Three types of service categories have been identified in CS–2: telecommunications services, which were also available in CS–1 service management; services, and service creation services, which are both new to CS–2. Telecommunication services are the standard IN services that are offered to subscribers by the operators. Service management services are defined for the following groups: service customization, service control, service monitoring, and other management services. Service creation services are grouped as follows: service specification, service development, service verification, service deployment, and service creation management.
ETSI is currently developing the corresponding CS–2 specifications for the European operators and vendors. It is expected that the specifications will be finalized by the end of 1998. The ETSI specifications are closely aligned with the ITU–T recommendations, except for the CUSF/SCF interface.
Telecommunication management network (TMN) provides the framework for standard modeling of telecommunications management services, management information, and management interfaces. Initiated by the ITU, the TMN framework defines network management architecture, composed of functional, physical, and informational elements, for a minimum platform to provide interoperability between network components and management systems. In CS–2, the service management functions are defined down to the distributed functional plane. The generic TMN protocols are expected to be used, with no modification to the INAP protocol foreseen.
Other initiatives supporting long-term evolution of IN are also in progress. The international Telecommunications Information Networking Architecture (TINA) consortium is seeking to develop an architecture that addresses open communications and applications that operate in a distributed computing and processing environment. However, this architecture is not backward-compatible, with the function-oriented IN service described in the INCM. In the TINA model, network functions are separated into a service segment that deals with service provisioning, and a delivery segment that provide functions for switching and transmission of information that is technology dependent. This model is more consistent with a manager-agent separation currently in use within computing network management standards.
IN is also impacting the mobility segment, as fixed-mobile convergence operations emerge. Current mobility systems have incorporated IN capabilities to support call routing, charging, handover, and other related mobility functions. There is current interest in merging mobility systems with the IN in a uniform approach (i.e. fixed mobile convergence), since IN already provides the required network intelligence for fixed networks. Future generation-mobility-systems standards, such as the universal mobile telecommunications system (UMTS) are being based on the IN architecture within ETSI.
Additional effort in supporting operator-specific services to mobility customers while roaming in visited, GSM–based networks is also underway through the Customized Applications for Mobile Network Enhanced Logic (CAMEL) initiative in ETSI. CAMEL defines the specifications necessary to offer IN services in a mobile environment. The CAMEL specifications are based on the ETSI Core INAP specifications. CAMEL Phase 1 was finalized in 1997, and provides basic call control. CAMEL Phase 2 has been completed in 1998, and offers more sophisticated capabilities, such as user interactions and charging.
