Adaptive Three-Layer Weighted Links Routing Protocol for Secure Transmission over Optical Networks MOHAMMED AL-MOMIN, JOHN COSMAS, SAMAN AMIN School of Engineering and Design Brunel University Uxbridge, Middlesex, UB8 3PH United Kingdom Mohammed.Al-Momin@brunel.ac.uk Abstract: - Bandwidth, latency and data security are the three major factors that affect the Quality of Service (QoS) for any computer network. Different applications running on a network have different requirements of these three factors, and dealing with all applications types in a similar manner is an inefficient approach. This paper proposes a routing protocol that recognizes the type of traffic and routes it accordingly to provide the optimal QoS. Different data types are to be routed through different routes to satisfy the preferred QoS requirements of these data types. The weights of the network’s links were partitioned in this paper into three layers to accommodate these three QoS requirements factors. Key Words: - QoS, Adaptive Weighted Routing, Latency, Secure Transmission, Optical Network. 1 Introduction A lot of works have been achieved to enhance the QoS of computer networks. The massive increase in the number of Internet users together with the rapid developments in the range of applications running over Internet has served as an incentive to encourage research towards finding an efficient routing technique. Data traffic on the Internet are not of the same types since they do not belong to a single application type. These different traffic types have different quality requirements and need to be dealt with differently. Some of the traffic over the Internet requires more bandwidth than others, whereas some other applications need less end-to-end delay (Latency). Furthermore, there are some other data that need to be dealt with most securely. For instance, phone-to-phone delay needs to be no more that 150 milliseconds to allow a comprehensible phone communications [1][2]. Non real time applications like web browsing and email are less delay sensitive, but loss sensitive instead, therefore the Internet operator should allocate a sufficient bandwidth for them, otherwise when there is network congestion they may be shed. When optical cable was first produced, it was considered to be immune against espionage. It has since been proven that it is not only possible to be insecure, but also, it could be simpler to tap than other predecessor technologies [3]. Some private information over the Internet such as VoIP and video telephony, in addition to their delay sensitivity, need to be transmitted securely without been revealed by eves droppers. The current Internet does not take into account the characteristics associated to each type of applications to assure an acceptable QoS [1][4]. This blind view to traffic leads to a uniform treatment of data traffic and consequently to a low quality of service. Metrics used in this paper to characterize applications’ QoS requirements are the Available Bandwidth, Latency and Security. This paper is organized as follows. Section 2 will describe the related works proposed to enhance the QoS in computer networks. In section 3, the three QoS requirement considered in this paper will be explained. In section 4, the proposed Three-Layer Weighted Link Routing Protocol (TLWLRP) will be explained. In section 5, an OMNeT++ model was created to simulate a sample optical network with the new routing protocol. Section 6 is concerned with the simulation results and their discussions. Finally, section 7 states some conclusions from this paper. 2 Related Works Research in the last decades focused on two issues of computer networking, namely, the QoS and the WSEAS TRANSACTIONS on COMMUNICATIONS Mohammed Al-Momin, John Cosmas, Saman Amin E-ISSN: 2224-2864 287 Issue 8, Volume 11, August 2012