On QoS Provisioning in ATM Networks
Anubhav Arora, John S. Baras · University Libraries (University of Maryland) · 2002
ATM is representative of the connection-oriented resource provisioning class of protocols. An ATM network is expected to provide end-to-end QoS guarantees to connections in the form of bounds on delays, errors and/or losses. Performance management involves measurement of QoS parameters, and application of control measures (if required) to improve the QoS provided to connections, or to improve the resource utilization at switches. QoS provisioning is very important for real-time connections in which losses are irrecoverable and delays cause interruptions in service. Most scheduling disciplines provide static allocation of resources at connection setup time. End-to-end bounds are obtainable for some schedulers, however these are precluded for heterogeneously composed networks. The resource allocation does not adapt to the QoS provided to connections in real-time. In addition, mechanisms to measure the QoS of a connection in real-time are scarce. A novel framework for QoS management is proposed in this paper to provide QoS guarantees to real-time connec-tions. It comprises of in-service QoS monitoring mechanisms, a hierarchical scheduling algorithm based on dynamic priorities that are adaptive to measurements, and methods to tune the schedulers at individual nodes based on the end-to-end measurements.