Multi-rate Circuit-switched Network Research Articles

Asymptotic Estimates for Blocking Probabilities in a Large Multi-Rate Loss Network

In this paper, asymptotic estimates for the blocking probability of a call pertaining to a given route in a large multi-rate circuit-switched network are given. Concentrating on low load and critical load conditions, these estimates are essentially derived by using probability change techniques applied to the distribution of the number of occupied links. Such estimates for blocking probabilities are also given a uniform expression applicable to both load regimes. This uniform expression is numerically validated via simple examples.

Asymptotic Estimates for Blocking Probabilities in a Large Multi-Rate Loss Network

In this paper, asymptotic estimates for the blocking probability of a call pertaining to a given route in a large multi-rate circuit-switched network are given. Concentrating on low load and critical load conditions, these estimates are essentially derived by using probability change techniques applied to the distribution of the number of occupied links. Such estimates for blocking probabilities are also given a uniform expression applicable to both load regimes. This uniform expression is numerically validated via simple examples.

On computing Markov decision theory-based cost for routing in circuit-switched broadband networks

In this paper, we study the problem of dynamic routing in multi-service circuitswitched networks. In a previous work, we have proposed a distributed, state dependent, dynamic routing method, called Least Cost Routing in Multi-Service Networks (LCRM), for multirate circuit-switched networks. Broadband Integrated Services Digital Networks (BISDN) should be capable of supporting a variety of traffic classes (e. g. data, voice, video, facsimile), each of which has its own traffic requirement (bandwidth requirement, call arrival rate, and call holding time) and reward parameter. The LCRM method is obtained through the policy iteration routine of Markov decision theory. It represents a one-step policy improvement on a base policy π0, with direct link routing only. The policy π0 also requires that each call class has a portion of link bandwidth dedicated to it. In this paper, we look for an efficient computational way to obtain the corresponding relative cost values, which represent the cost of routing a call over one link. We consider the one-linke model with two types of traffic. We show that the system of linear equations associated with the two-dimensional Markov chain can be decomposed into a system of linear equation associated with the one-dimensional Markov chain. Examples with two classes of service are presented.

Link access blocking in very large multi-media networks

This paper is concerned with performance models and approximations for very large, multi-media networks. Blocking is the traditional performance measure in circuit-switched networks, and will remain as such in multi-rate circuit-switched networks. It is also considered a likely performance measure candidate for resource management and dimensioning in broadband fast packet-switched networks, operated under virtual circuit mode. To gain some insight into network-wide blocking phenomena, we study in this paper the basic building block of any network, a single link. Multi-media traffic calls with Poisson arrivals, arbitrarily distributed service times, and different bandwidth requirements (in number of circuits), are offered to a system (link) of finite capacity. A call is rejected when the sharing policy doesn't allow it to be accommodated by the system. Under complete sharing policy, an aggregate state describing the number of occupied circuits is shown to exhibit a product form solution in steady state, when the capacity and traffic intensities become very large asymptotically. This structural property leads to the main result of this paper, an approximation which reduces the computation of the blocking probabilities for the different classes of traffic to the evaluation of a single Erlang formula and the determination of the root of a monotonous polynomial function. We provide comparison curves of the exact blocking probabilities and the approximations for some examples with 3 classes of traffic.