Traffic shaping in ATM and IP networks using standard end systems

Providing Quality of Service (QoS) is one big goal of ATM networks. Looking at ATM networks, it becomes obvious that QoS-support requires many components on different layers working together. QoS has to be provided bottom-up from the network interface card up to the higher protocol layers and the applications. A basic building block for providing QoS on the higher layers is traffic shaping. This well-known mechanism of ATM will also be used in future QoS-enhanced IP networks, be it Integrated or Differentiated Services networks. This paper deals both with the preconditions necessary for efficient traffic shaping in ATM end systems and with the problems of traffic shaping in future TCP/IP networks. It presents concepts and measurements of a driver optimized for traffic shaping in ATM end systems, describes the implementation of a high-resolution timer for Linux, and discusses problems arising especially in TCP/IP networks.