Congestion controls are a key factor in achieving the robust performance required of common channel signaling (CCS) networks in the face of partial network failures and extreme traffic loads, especially as networks become large and carry high traffic volume. The CCITT recommendations define a number of types of congestion control, and the parameters of the controls must be well set in order to ensure their efficacy under transient and sustained signalling network overload. The objective of this paper is to present a modeling approach to the determination of the network parameters that govern the performance of the SS7 congestion controls under sustained overload. Results of the investigation by simulation are presented and discussed.>

The traffic performance of time-space-time (TST) switching networks built from large time-switching stages used in digital switching systems is discussed. These switching networks exhibit steep load-service characteristics and present new numerical problems for traffic performance evaluation. The precise numerical calculation of switch blocking and the amount of search effort needed to find a network path are addressed. Computational efficiency and robustness are emphasized. The approach is based on a familiar model that uses state-dependent transitions in formulating the balance equations. A comparative study with traditional methods illustrates the numerical gains to be made for switching networks of arbitrary size.>

A Markovian queueing model with finite waiting space is developed for the communications controller which buffers the flow of packets from a host computer to its associated packet switch. The segmentation of messages into packets by the host is modeled by a batch input to the communications controller. The probabilities of state are determined by numerical recursion and subsequently used in expressions developed for the blocking probabilities and waiting-time distribution as a function of two proposed batch acceptance strategies. Representative numerical results as would be useful in the dimensioning and performance analysis of the communications controller are presented. A more general non-Markovian model is investigated by means of simulation, showing that the initial Markovian model is very accurate in determining the system performance.

A method is proposed for the analysis of a teletraffic network with alternative routing. The approach used is to model a "general link" as a separate entity, being a first step towards analyzing the network in a link-by-link fashion. To this end the general link is considered to be a group of fully available trunks offered a number of separate streams of traffic. By considering the multivariate point process formed by the total stream of arriving calls, the individual streams of traffic overflowing from, and the individual streams of traffic carried on the common trunk, are distinguished. All streams of traffic in the network are considered to be well described by simple renewal processes. The validity of the method is illustrated with exact numerical results and by simulation.

In this paper is a formulation of the one-moment method of analysis for a telephone traffic network in terms of the link offered traffics. By using a slightly strengthened version of the assumptions hitherto used in one-moment analysis, and by developing a type of limited availability link model, it is shown how the offered traffic to each link may be found, and thus how the network analysis may be reduced to a valid set of link analyses.