"A study of any object needs to take into account not only the interconnections between different components within the object@ but also the object's external relationships. Through external relationships@ the object performs its functions in the context of an overall system. However@ these interrelationships may pose a risk due to a variety of threats that can disturb the functioning of the object. A study of these objects is particularly important for a telecommunication IP-based network security system (TNSS)@ which needs to protect a telecommunication IP-based network mainly against external threats Possible composition of technical components of a telecommunication IP-based network is presented in Appendix I. The TNSS does not function as a free-running system; it works in close interaction with a number of external systems. Firstly@ these external systems include the telecommunication IP-based network itself@ which protects the TNSS. The principles that govern the construction of the transport medium and the service platforms directly determine the requirements and@ therefore@ the design of the TNSS. Secondly@ these external systems include the telecommunication IP-based network users whose requirements should be fulfilled by the telecommunication IP-based network and its TNSS. Some other external organizations can also affect the TNSS construction principles. These organizations include: ?C national regulatory authorities; ?C trusted third parties providing services for security systems (on the ""outsourcing"" principle); ?C organizations using telecommunication IP-based network services for the creation of information networks. In essence@ the main TNSS tasks consist of the protection of the telecommunication IP-based network and the information transmitted through this network against the various external security threats in the environment in which the TNSS functions. The above list indicates that TNSS has interrelationships with many external objects which may be subdivided into several groups. TNSS interrelationships with external objects can either directly or indirectly affect the TNSS requirements@ the TNSS construction and the functioning principles. Therefore@ these interrelationships should be taken into account in the course of TNSS development. Existing ITU-T Recommendations address certain aspects of this problem (for example@ [ITU-T X.842] and [ITU-T X.843] address interrelationships with a trusted third party). However@ there are many aspects of TNSS interrelationships with external objects that have not yet been considered. This Recommendation covers a general architecture of TNSS interrelationships with external objects. This architecture can be applied to various types of telecommunication IP-based networks and to various telecommunication security systems. This Recommendation provides an overview of all external interrelationships of TNSS. This Recommendation may serve as a basis for elaborating more detailed recommendations on network security@ with respect to the effect on external objects."