QoS routing algorithms for multiple traffic classes

One of the most important features of the next generation Internet is the ability to provide quality of service (QoS) guarantee. Recent developments in the Internet provide at least two types of service. For example, guaranteed service and controlled load service in Integrated Services networks, and expedited forwarding and assured forwarding in Differentiated Services networks. Providing guaranteed service and expedited service, referred to as bandwidth-guaranteed traffic, requires reservation of a fixed amount of bandwidth while controlled load service and assured forwarding service, referred to as fair-shared traffic, requires reservation of a minimum amount of bandwidth to ensure finite queue length. Routing in a network with these two types of service should take their traffic and QoS characteristics into consideration. In this paper, we propose two routing algorithms that use different cost functions and routing strategies when routing different classes of traffic. Our simulation results show that the proposed soft routing algorithm is able to yield low blocking probability for bandwidth-guaranteed traffic and high max-min fair share rate for fair-shared traffic under various traffic conditions.