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Network-oriented load control for SS.7/IN

Dublin City University. School of Electronic Engineering
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  • Computer Networks
  • Electronic Engineering
  • Telecommunications
  • Network Load
  • Communication


Intelligent Network (IN) systems are today the prevalent means of providing services based on manipulation of voice call set-up in the public telecommunications infrastructure. As INs are evolving into more dynamic and open service delivery platforms, it is becoming increasingly difficult to dimension them to meet the performance requirements of a dynamically changing set of services. This is leaving networks more susceptible to overloads, which result in end-user dissatisfaction and revenue loss for the operator. In this context, load control strategies that protect against harmful overloads, are of critical importance. Load control in IN systems and underlying Signalling System No.7 (SS.7) networks is characterised by node-oriented strategies centred on the protection of individual network resources, without regard to overall network performance. We argue that, given current and future increases in number and usage of IN services, node-oriented load controls cannot guarantee that desired performance levels are consistently achieved. Instead, we advocate adoption of network-oriented approaches that seek to optimise the usage of network resources from a global, rather then localised, perspective. We first present a detailed analysis of standard SS.7 and IN node-oriented controls that demonstrates their inherent flaws and shows that they can interact poorly when invoked simultaneously. We then specify a load control that is based on explicit allocation of critical resources in a profit-optimal manner and that employs a token-based paradigm. This strategy is shown to perform at least as well as two node-oriented strategies in the context of controlling a single IN Service Control Point (SCP). More significantly, we introduce strategy enhancements that provide the following: co-ordinated, profit-optimal control over multiple resource types of varying characteristics; minimisation of the load of the SS.7 network; and reaction to SS.7 overloads or equipment failures. The enhanced strategy represents a highly efficient and flexible network-oriented control solution for SS.7/IN.

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