Modelling and analysis of routing and resource allocation techniques in multi‐service networks

Abstract

In this paper a novel call level model based on the extension of the classical Erlang multi-rate model for broadband integrated services networks is proposed. We use the model to study routing strategies in multi-service networks where service classes with/without QoS guarantees coexist. Examples for such networks include ATM and IP-based integrated networks. In ATM, the CBR and VBR service classes provide QoS guarantees, while the ABR and UBR service classes are of the best effort type. In IP, traditional TCP/IP traffic is of the best effort type, while new protocols like the RSVP or the differentiated services with central resource handling attempt to support QoS parameters. The coexistence of guaranteed and best effort traffic gives rise to new challenging problems since for a given elastic (best effort) connection the bottleneck link determines the available bandwidth and thereby puts constraints on the bandwidth at the other links along the connection's path. Since the available bandwidth fluctuates in time following the load on the links, routing and link allocation in this environment together with blocking probability calculations and fairness issues need to be studied. By means of our proposed model we are able to conduct a survey of various routing and link allocation techniques as well as to develop a modified shortest path routing algorithm which, according to the numerical examples, performs well in this environment. Figure 9. Impact of partial blocking and queueing on total call holding times of: (a) ABR1 sources and (b) ABR2 sourcesAll in all, from the numerical results we conclude that in PB-Q systems, which we have used as models for multi-rate 'per-session state aware' connection-oriented networks, there are a number of means to control blocking probabilities and thus network resource utilization and fairness. As we have seen on the numerical examples, call queueing and partial blocking, in general, decreases the blocking probabilities at the expense of increased holding times. We are currently working on the formulation of optimization criteria and an optimization model for the PB-Q system. Relationship to and comparison with related works Related worksRouting high-bandwidth traffic in a fair manner and resource allocation in multi-service networks supporting best effort (also called 'elastic') traffic are the topics of current state-of-the-art research papers.\\ Also, the issue of fairness is in the focus of both the ITU-T and the ATM Forum. Although these papers delve into important aspects of fairness 117

Neural approximation of team optimal dynamic routing in IP networks

“…Correspondingly, similar techniques carry out to the ATM networking context [1], [5], [6] and [7], where routing is effected under Quality of Service (QoS) constraints at cell-level. In another respect, [8], [9] and [10] consider optimization problems in routing based on flow-level information, possibly with QoS constraints, but without a dynamic control formulation.…”