Telephonic communications – Special services
Reexamination Certificate
1998-05-12
2002-09-03
Matar, Ahmad F. (Department: 2642)
Telephonic communications
Special services
C379S201050, C379S207020
Reexamination Certificate
active
06445782
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to service management systems for use in communications networks and finds particular application in managing interactions between service features.
2. Description of the Related Art
Communications systems have become so large and complex that it has become difficult to predict the occurrence of possible interactions among their components. These interactions can result in the loss of intended functionality or cause unforeseen side-effects.
Modelling communication systems as dynamic constraint satisfaction problems is proposed as a means of performing avoidance, detection, and resolution of interactions. Methods for isolating the components responsible for the interaction are also discussed, as are ways of automatically generating inferences about them.
Communications systems have come a long way from providing simple telephone service. As the list of services provided has increased, so has the underlying complexity of the system. In the US, heterogeneity of service providers has compounded the problem by being based on inhomogeneous hardware and software. Even for a single service provider, the underlying networks and protocols can differ depending upon usage and types of services provided. The result is an incredibly large and complex system whose operation can be viewed as multiple levels of functional and logical abstraction. The management of such a system, such that consistent and high quality service is maintained, can become an overwhelming task.
A burr in the heel of consistent and high quality communications service is the feature interaction problem. Roughly speaking, features can be considered the services provided by the communications system. The potential problem that can arise, especially today with a large, increasing number of features available, is that different features, or multiple instances of the same feature, can cause unforeseen and unintended behaviour when operating together. An example of feature interaction is as follows:
Consider two common features provided to phone customers: call waiting (CW) and call forwarding on busy (CFB). Call waiting notifies the call recipient, who is already on the line, of an incoming call and allows the recipient to switch between the two calls, connecting with one, suspending the other. Call forwarding on busy, which engages when the recipient is already on the line, allows the recipient to have calls directed to another number. This features do not notify the call recipient. Both CW and CFB connect as normal calls when the recipient is not busy.
Separately, each feature can operate without any interaction. However, when both features are activated and the recipient is busy, interaction occurs, due to the fact that neither feature can be performed without sabotaging the operation of the other. Specifically, there are two different and conflicting actions to be performed when the call recipient is busy.
In “Feature Interactions in Telecommunications Systems”, by E. Jane Cameron and Hugo Velthuijsen, published in the IEEE Communications Magazine Vol. 31, No. 3, pp 18-22, August 1993, three fundamental aspects of feature interaction problems are listed as avoidance, detection, and resolution.
The idea of avoidance of feature interaction is that relevant specifications are made clear enough that conflicts do not occur between features, whether in the design phase or at the point they are invoked. Avoidance can be extended to include those cases where it might have occurred, yet alternatives existed that allowed the features to be invoked without interaction.
Detection of interaction is useful in a number of stages. It can be used as a guide to designers at the point that they are creating new features and can also inform the system or the user of possible conflicts at the point a feature is added or invoked.
In order for the information to be useful, some sort of resolution is to be expected, such as all or some of the features involved in the conflict being modified or removed.
Published efforts have focused on providing examples of interactions and categorising the different ways they can occur, such as in “A Feature Interaction Benchmark for IN and Beyond”, by Cameron et al, IEEE Communications Magazine, Volume 31, No. 3, pp 64-69, 1993. In this publication, the authors attempt to classify various types of interaction based upon the basic cause of the interaction and posit that much of the problem is the failure to specify clearly a feature's intended behaviour. In “A Method for Detecting Service Interactions”, by Wakahara et al, IEEE Communications Magazine, Volume 31 No. 8, pp 32-37, the occurrence of feature interaction is attributed to a system's lack of three types of knowledge, such as the implicit relationships among features, yet no systematic approach is given that could be automated to acquire this information. In “Specifying Telephone Systems in LOTOS and the Feature Interaction Problem”, by Boumezbeur et al, IEEE Communications Magazine, Volume 31 No. 3, pp 38-45, August 1993, the use of LOTOS as a tool to model interaction is presented, where features' processes and subprocesses can be represented and then symbolically executed to detect interaction. In “A Practical Approach to Service Interaction”, by Kuisch et al, IEEE Communications Magazine, Volume 31 No. 3, pp 24-31, 1993, interaction is viewed as overlapping or intersecting control intervals within a high-level framework known as the Basic Call State Model. “Service Interaction in an Object-Orientated Environment”, by Mierop et al, IEEE Communications Magazine, Volume 31 No. 8, pp 46-51, 1993, suggests an object-oriented approach in which feature interaction corresponds to the common use of a basic call object by two or more features. A more distributed approach is given in “The Negotiating Agents Approach to Runtime Feature Interaction Resolution”, by Griffeth et al, published in “Feature Interactions in Telecommunications Systems”, at pp 217-234, edited by W Bouma and Hugo Velthuijsen, 1994, where the process of creating a situation free of interaction is viewed as a negotiating process between agents.
BRIEF SUMMARY OF THE INVENTION
According to the present invention, there is provided a feature interaction management system, for use in the provision of communications services over a communications network by means of running call processing logic to control the network, wherein the feature interaction management system comprises:
(i) access to a feature representation store for storing constraint-based representations of service features;
(ii) a scenario simulator for providing simulations of call instance scenarios involving at least one communications service feature; and
(iii) a conflict detector for detecting conflicts between feature representations in a simulated call instance scenario,
wherein the conflict detector is adapted to detect conflicts by generating at least one constraint satisfaction problem and detecting inconsistencies in the constraint satisfaction problem, the problem comprising at least two constraint-based feature representations and a set of values for call instances, the set of values being provided by a simulated call instance scenario.
It will be understood that references to “calls” and “call processing” should be taken as references to connections generally in a communications network, for the provision of voice, data or other services, a call potentially being established for instance between equipment with no human presence.
Preferably, the system further comprises a resolution generator for receiving detected conflict information from the conflict detector and for generating at least a partial resolution to a detected conflict.
Constraint satisfaction is a known approach to problem solving but in quite different domains, such as scheduling.
A management system according to an embodiment of the present invention might be associated with a service creation environment and/or a service delivery system. Hence, conflic
Azarmi Nader
Corley Stephen L.
Elfe Charles D.
Freuder Eugene C.
Lesaint David
Agdeppa Hector
British Telecommunications public limited company
Matar Ahmad F.
Nixon & Vanderhye P.C.
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