EFFECTIVE ' BANDWIDTH MANAGEMENT OF ATM ABR CONNECTIONS BY USING MINIMUM INTER RM CELL TIME

Abstract

The capability of Asynchronous Transfer Mode (ATM) networks to provide large bandwidth and to handle multiple Quality Of Service (QOS) support can only be realized by preparing effective traffic management mechanisms. ATM networks have multiple service classes for audio, video and data to share the same network. Of these the Available Bit Rate (ABR) service class is designed to efficiently support data traffic. Traffic management involves the design of a set of mechanisms which ensure that the network bandwidth, buffer and computational resources are efficiently utilized while meeting the various Quality of Service (QoS) guarantees given to sources as part of a traffic contract. Several rules are specified for source, destination and switches present in the ATM network to use particular service class efficiently. In this dissertation, we address some modification to the current source rule number 3 for the ABR service class to achieve efficient utilization of link bandwidth for high-speed connections only. We consider three aspects of this problem in this dissertation. First, the current source end system rule (SES) number 3 is evaluated to know how it works. SES rule number 3 says that for every 31 data cells one RM cell should be sent. Second, another technique for high-speed connections is provided by increasing the ABR service parameter Nrm. Since the inter RM cell time for high-speed connections is less compared to low-speed connections, one can increase Nrm value to avoid unnecessary control information. Third, a modified technique is introduced by modification to SES rule number 3 (with additional parameter MIRCT). This will form a coupling between switch averaging interval (AI) and inter RM cell time by which the parameter Minimum Inter RM Cell Time (MIRCT) reduces the control information and increases bandwidth for data cells. In summary, this dissertation work addresses the current SES rule number 3 for ATM ABR connections and the techniques developed that are applicable to high speed ABR connections for greater efficiency than SES rule number 3. in