Connection-based multiplexers: an alternative for traffic shaping in ATM networks

In high speed networks, such as ATM based, traffic issued from applications requiring various qualities of service (QoS) are transported over the same physical links and share a common set of resources. To guarantee these services, networks must implement very efficient control mechanisms, both at call setup (call admission control) and during the connection steady state (policing). For every cell entering the network, its compliance with the traffic contract is verified by the policing mechanism. Cell clumping, which is characteristic of bursty traffic, may induce erroneous estimations of this conformance and lead to cell discard. Shaping mechanisms may then be used to smooth traffic burstiness by reducing the clumping effect. The present paper focuses on a particular class of shaping methods, for which the minimum inter-cell spacing is defined at call setup using a calendar-based multiplexer. A specific algorithm, based on a weighted pseudo-correlation (WPC), is presented and evaluated.