The Optimal Virtual Path Design of ATM Networks

This paper studies the optimal configuration of virtual paths in ATM networks. A linear model that minimizes the maximum flow density of links is proposed for the optimal virtual path configuration. The advantage of the modeling is that traffic loads are distributed evenly over entire network. An algorithm based on the multi-commodity approach is proposed to solve the problem. Examples are given to show that this algorithm solves the optimal VP assignment problem very quickly and efficiently. Since only single source-destination linear programming subproblems need to be solved in our approach, this algorithm can be applied to large-scale networks.published_or_final_versio

Wireless ATM layouts for chain networks

In this paper we consider the problem of constructing ATM layouts for wireless networks in which mobile users can move along a chain of base stations. We first show that deciding the existence of a layout with maximum hop count h, load l and channel distance d is NP-complete for every fixed value of d greater or equal to 1. We then provide optimal layout constructions for the case d less than or equal to 2. Finally, optimal layout constructions are obtained also for any d within the class of the so-called canonic layouts, that so far have always been shown to be the optimal ones

Bandwidth Allocation By Pricing In ATM Networks

Admission control and bandwidth allocation are important issues in telecommunications networks, especially when there are random fluctuating demands for service and variations in the service rates. In the emerging broadband communications environment these services are likely to be offered via an ATM network. In order to make ATM future safe, methods for controlling the network should not be based on the characteristics of present services. We propose one bandwidth allocation method which has this property . Our proposed approach is based on pricing bandwidth to reflect network utilization, with users competing for resources according to their individual bandwidth valuations. The prices may be components of an actual tariff or they may be used as control signals, as in a private network. Simulation results show the improvement possible with our scheme versus a leaky bucket method in terms of cell loss probability, and confirm that a small queue with pricing can be efficient to multiplex heterogeneous sources

Topological Design of Multiple Virtual Private Networks UTILIZING SINK-TREE PATHS

With the deployment of MultiProtocol Label Switching (MPLS) over a core backbone networks, it is possible for a service provider to built Virtual Private Networks (VPNs) supporting various classes of services with QoS guarantees. Efficiently mapping the logical layout of multiple VPNs over a service provider network is a challenging traffic engineering problem. The use of sink-tree (multipoint-to-point) routing paths in a MPLS network makes the VPN design problem different from traditional design approaches where a full-mesh of point-to-point paths is often the choice. The clear benefits of using sink-tree paths are the reduction in the number of label switch paths and bandwidth savings due to larger granularities of bandwidth aggregation within the network. In this thesis, the design of multiple VPNs over a MPLS-like infrastructure network, using sink-tree routing, is formulated as a mixed integer programming problem to simultaneously find a set of VPN logical topologies and their dimensions to carry multi-service, multi-hour traffic from various customers. Such a problem formulation yields a NP-hard complexity. A heuristic path selection algorithm is proposed here to scale the VPN design problem by choosing a small-but-good candidate set of feasible sink-tree paths over which the optimal routes and capacity assignments are determined. The proposed heuristic has clearly shown to speed up the optimization process and the solution can be obtained within a reasonable time for a realistic-size network. Nevertheless, when a large number of VPNs are being layout simultaneously, a standard optimization approach has a limited scalability. Here, the heuristics termed the Minimum-Capacity Sink-Tree Assignment (MCSTA) algorithm proposed to approximate the optimal bandwidth and sink-tree route assignment for multiple VPNs within a polynomial computational time. Numerical results demonstrate the MCSTA algorithm yields a good solution within a small error and sometimes yields the exact solution. Lastly, the proposed VPN design models and solution algorithms are extended for multipoint traffic demand including multipoint-to-point and broadcasting connections

Saturation routing for asynchronous transfer mode (ATM) networks

The main objective of this thesis is to show that saturation routing, often in the past considered inefficient, can in fact be a viable approach to use in many important applications and services over an Asynchronous Transfer Mode (ATM) network. For other applications and services, a hybrid approach (one that partially uses saturation routing) is presented. First, the minimum effects of saturation routing are demonstrated by showing that the ratio, defined as f, of routing overhead cells over information cells is small even for large networks. Second, modeling and simulation and M/D/l queuing analysis techniques are used to show that the overall effect on performance when using saturation routing is not significant over ATM networks. Then saturation routing ATM implementation is also provided, with important extensions to services such as multicast routing. After an analytical comparison, in terms of routing overhead, is made between Saturation Routing and the currently proposed Private Network-Network Interface (PNNI) procedure for ATM routing made by the ATM forum. This comparison is made for networks of different sizes (343node and 2401 -node networks) and different number of hierarchical levels (3 and 4 levels of hierarchy). The results show that the higher the number of levels of hierarchy and the farthest (in terms of hierarchical levels) the source and the destination nodes are from each other, the more advantageous saturation routing becomes. Finally, a set of measures of performance for use by saturation routing (or any routing algorithm), as metrics for routing path selection, is proposed. Among these measures, an innovative new measure of performance derived for measuring quality of service provided to Constant Bit Rate (CBR) users (e.g., such as voice and video users) called the Burst Voice Arrival Lag (BVAL) is described and derived

Simulation of LAN Interconnection via ATM

http://www.worldcat.org/oclc/3088061

Análisis y evaluación de los sistemas de protección contra la congestión en la red digital de sevicios integrados de banda ancha

Postprint (published version

Statistical multiplexing and connection admission control in ATM networks

Asynchronous Transfer Mode (ATM) technology is widely employed for the transport of network traffic, and has the potential to be the base technology for the next generation of global communications. Connection Admission Control (CAC) is the effective traffic control mechanism which is necessary in ATM networks in order to avoid possible congestion at each network node and to achieve the Quality-of-Service (QoS) requested by each connection. CAC determines whether or not the network should accept a new connection. A new connection will only be accepted if the network has sufficient resources to meet its QoS requirements without affecting the QoS commitments already made by the network for existing connections. The design of a high-performance CAC is based on an in-depth understanding of the statistical characteristics of the traffic sources

Virtual topology design for optical WDM networks

Master'sMASTER OF ENGINEERIN