Analysis of QoS and Traffic Management Issues in Multimedia Services

Abstract

As the world is moving more and more towards mobile hand-held devices, the amount of multimedia data on communication network is growing enormously. Providing a good quality of application support is a major challenge in this scenario. The Quality of Service(QoS) requirements differ for different types of applications. QoS provi- sioning is afected by various layers of Open Systems Interconnection(OSI) model. Wired networks are less prone to errors as compared to wireless networks. There are two major types of wireless networks; infrastructure-less and infrastructure based networks. Mobile Ad hoc Network(MANET) is a network formed by the mobile de- vices without any pre-installed infrastructure. MANETs are self organizing in nature, where networks are created instantaneously. The data on communication network, hugely comprises of multimedia data which is sent to many receivers by a single or multiple sources. In such scenario when unicast is used, same data is sent as many times as there are receivers, making inappropriate use of network resources. Multicasting provides a solution to this problem. It dupli- cates a data packet only when necessary. However, multicast alone cannot ascertain seamless transfer of data. Providing this assurance of QoS alongwith multicast is a difficult task due to the dynamic nature of topology and certain other inherent prop- erties of MANET. Also, the Integrated Services (IntServ) and Differentiated Services (DiffServ) models of QoS provisioning on wired networks cannot be used in its origi- nal form in the wireless networks. Discovering optimal multicast routes is an NP-Problem and QoS based routing of multimedia traffic is all the more a complicated optimization problem. Such problems are computationally intractable, also because the network state is inaccurate, which is a common scenario in MANET. In this research work, a hybrid MANET architecture has been proposed for managing multimedia data transmission using a combination of reactive and proactive approach of routing over a clustered framework. The pro- tocol starts with the election of cluster heads using QoS based enhanced weighted clustering mechanism. Ant Colony Optimization(ACO), which is a categorization of Swarm Intelligence(SI) is known for giving dynamic, adaptive, and intelligent solu- tion to combinatorial optimization problem. It is used for a more optimized solution to cluster head election in dense MANET with changing patterns of mobility. The route Including approach incorporates reactive routing approach for optimized routing solution between the cluster heads. The proactive path maintenance, comprises of route maintenance between the nodes within a cluster. The multimedia data transmission starts after the routes are established. The multimedia traffic prioritization algorithms sets the highest priority to the referential frames, to minimize playback delay and jitter, since, the loss of those frames has a higher impact on the video quality. The analysis of the proposed protocol shows a considerable improvement in the throughput, delay and control overhead. ACO based implementations though known to provide an optimal solution may suffer from stag- nation problems, due to reduced exploration of newer paths over a period of time and the best path being selected repeatedly. In this research work, rather than switching to different path after congestion, the total load is divided into multiple paths as per the priority of the multiple frame types. Hence, stagnation problems are minimized leading to better quality of multimedia transmission.