A comparison of SS7 congestion control options during mass call-in situations

The ITU-T (International Telecommunications Union, Telecommunications Standardization Sector, formerly known as CCITT), in its specification of the SS7 protocol, describes a number of alternatives for congestion control. In this paper we provide a direct comparison of the effectiveness of some of these methods in dealing with a mass call-in situation. We find that the international option provides better call throughput and is more robust to threshold settings and delays in feeding back congestion information than the national option with congestion priorities and a combination of the two options. The results can provide guidance to those attempting to define application level overload procedures, to those studying internetworking issues for connection between countries employing different SS7 congestion control options, and to those preparing to formulate B-ISDN overload strategies.<
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