Year

2000

Degree Name

Master of Engineering (Hons.)

Abstract

Both the Available Bit Rate (ABR) and Unspecified Bit Rate (UBR) services in Asynchronous Transfer Mode (ATM) networks cater for data traffic. The network guarantees low cell loss as a parameter for Quality of Service (QoS) in the ABR service, but not in UBR service. In order to achieve a low cell-loss ratio (CLR) for the ABR service, it is critical for the network to adopt suitable traffic management functions before and after the admission of a call. Before any call admission, the network reserves resources through the Call Admission Control (CAC) function, based on the agreed traffic contract. After a call admission, the network monitors, through a policing function, any violation of the source rate and behaviour agreed to in the contract. The policer checks the conformance (as per the conformance definition [1]) of incoming cells, passes those which do conform and tags/discards those which do not conform. The performance accuracy of a policer plays a key role in a network's ability to meet the guaranteed QoS. Any errors in the policing algorithm leads to poor performance, with a potential QoS short fall. This thesis proposes a performance measurement method for the ABR policer.

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