Hysteretic Control Technique for Overload Problem Solution in Network of SIP Servers

This paper contains research and development results concerning application of hysteretic control principles to solve SIP servers overload problem, which is known from a number of IETF standards and scientific papers published over the past few years. The problem is that SIP protocol, being the application layer protocol, by default has no build-in means of overload control, as, for example, SS7, MTP2 and MTP3 protocols. It was the SS7 network, where a threshold mechanism of hysteretic signalling load control was first implemented. In this paper we describe the main up-to-date solutions of an overload control problem in a signalling network, and develop analytical models of hysteretic control, which are useful in the development of load management functions of SIP servers. We also propose the design of Open SIP signalling Node (OSN) software architecture which is intended to be used for simulations and comparison of various overload control mechanisms

On truncations for weakly ergodic inhomogeneous birth and death processes

We investigate a class of exponentially weakly ergodic inhomogeneous birth and death processes. We consider special transformations of the reduced intensity matrix of the process and obtain uniform (in time) error bounds of truncations. Our approach also guarantees that we can find limiting characteristics approximately with an arbitrarily fixed error. As an example, we obtain the respective bounds of the truncation error for an Mt/Mt/S queue for any number of servers S. Arbitrary intensity functions instead of periodic ones can be considered in the same manner

Stability bounds for M t /M t /N/N + R queue

ABSTRACT We study Mt/Mt/N/N +R queue and obtain stability bounds for main characteristics of the respective queue-length process

Development of radio admission scheme model for 5G network slicing framework as a retrial queue

To improve the efficiency of using network resources, fifth-generation 5G networks propose to use the technology of network slicing. This feature consists of creating multiple logical, self-contained networks on top of a common shared physical infrastructure, and, therefore, it can be used to support multi-tenancy on the 5G network. Each of these logical networks is referred to as a network slice and can be tailored to provide a particular system behavior to best support specific service/application domains. This work is devoted to the development of a mathematical model of resource allocation in network slicing. Using the firstorder asymptotic analysis method, we will find basic numerical and probabilistic characteristics

Ergodicity and Perturbation Bounds for Inhomogeneous Birth and Death Processes with Additional Transitions from and to the Origin

Service life of many real-life systems cannot be considered infinite, and thus the systems will be eventually stopped or will break down. Some of them may be re-launched after possible maintenance under likely new initial conditions. In such systems, which are often modelled by birth and death processes, the assumption of stationarity may be too strong and performance characteristics obtained under this assumption may not make much sense. In such circumstances, time-dependent analysis is more meaningful. In this paper, transient analysis of one class of Markov processes defined on non-negative integers, specifically, inhomogeneous birth and death processes allowing special transitions from and to the origin, is carried out. Whenever the process is at the origin, transition can occur to any state, not necessarily a neighbouring one. Being in any other state, besides ordinary transitions to neighbouring states, a transition to the origin can occur. All possible transition intensities are assumed to be non-random functions of time and may depend (except for transition to the origin) on the process state. To the best of our knowledge, first ergodicity and perturbation bounds for this class of processes are obtained. Extensive numerical results are also provided

The approximation of response time of a cloud computing system [АППРОКСИМАЦИЯ ВРЕМЕНИ ОТКЛИКА СИСТЕМЫ ОБЛАЧНЫХ ВЫЧИСЛЕНИЙ]

Cloud computing is an evolutionary technology that allows a remote user to gain access to resources through Internet services. The article discusses the cloud computing system, which receives complex user queries consisting of several subqueries. The allocation of one unit of the resource is required for processing each subquery. Accurate assessment of effectiveness of cloud computing resources is a prerequisite to ensure the required quality of service. Response time, i. e., the maximum of subqueries service times, is chosen as an indication of effectiveness of a cloud computing system. To analyze the characteristics of response time, a simplified mathematical model of a cloud system was constructed as a queuing system with single Poisson input flow of requests and several subsystems (a buffer and a server). Each request at the instant of arrival is divided into several parts, each of which is served by its queuing subsystem with unlimited storage capacity with exponentially distributed service time. The analytical formulas for approximation of mean response time and its variance are presented. To assess the accuracy of the approximation, a GPSS (General Purpose Simulation System) model was constructed. © 2015 Federal Research Center "Computer Science and Control" of Russian Academy of Sciences. All rights reserved

On performance analysis of modern wireless networks [К АНАЛИЗУ ПОКАЗАТЕЛЕЙ КАЧЕСТВА ОБСЛУЖИВАНИЯ В СОВРЕМЕННЫХ БЕСПРОВОДНЫХ СЕТЯХ]

Analytics predict that worldwide mobile traffic growth rate will exceed fixed traffic approximately three times from 2014 to 2019. Number of mobile users will increase up to 4.9 billions and mobile devices number will exceed 10 billions. The average mobile network connection speed (1.7 Mbps in 2014) will reach nearly 4.0 Mbps by 2019. Special attention should be paid to mobile video traffic that will reach three-fourths of the whole mobile traffic by 2019. These tendencies bring new challenges for mobile communication providers to increase efficiency and additivity of radio resource allocation. In this connection, the paper analyzes a simplified model that allows one to obtain analytical estimates of the blocking probability and the average value of occupied resources according to the resource allocation policy of the LTE-Advanced technology. © 2015 Federal Research Center "Computer Science and Control" of Russian Academy of Sciences. All rights reserved