George Pavlou, David Griffin
University College London, UK

The ITU-T have distinguished between the management and control planes in the operation of communications networks and introduced the Telecommunications Management Network (TMN) as a means of provisioning management services.

The Intelligent Network (IN) addresses the separation of service control logic from core-network routing logic and has two aspects: the off-line service creation process and the service operation aspects in which new logic is used to intercept in the call establishment process and interpret/redirect it accordingly. The latter procedure takes place in the control plane via signalling mechanisms. Service creation is concerned with the initial generation of the logic involved while deployment procedures are used to plant it in the IN infrastructure - the process referred to as "service management" in IN. An interpreted scripting architecture is used so that existing compiled logic does not need to be updated.

On the other hand, the TMN is a conceptually separate data network overlaid on the telecommunications infrastructure being managed. This monitors network/service resources through object-oriented abstractions and may perform intrusive actions to modify the way the network operates. The key difference to IN is that normal network operation (e.g. signalling procedures for call set-up) are not affected as the whole operation takes place "outside" the managed network. The TMN should complement and enhance the control plane functions by configuring operational parameters and, in general, it has less stringent requirements on real-time response

The two approaches have a lot of similarities and some important differences but are complementary in general and as such there is scope for their integration. Control affects the way the network operates and although the current IN architecture operates without the need to change the underlying signalling mechanisms, there are limits as to how far this approach may reach before such changes are necessary, especially when service types other than those following the traditional call model are considered. On the other hand, the TMN operates outside the managed network and can be (almost) infinitely extended in functionality, as far as adequate provision for such functionality exists through abstractions of all the possible IN resources. Because the TMN functionality is logically, and often physically, outside of the network itself and separate from the control plane, it is unable to react as quickly to network events as control plane functionality including IN features. However, this does not mean that the TMN approach is inferior in any way to the approach of IN, the management systems provided by the TMN are complementary to the signalling plane and in general are not involved in real-time decision making processes to the same extent as the control plane features.

Back to my publications page