End-to-end delay analysis for small/medium scale IP networks

Analysis of multiplexers with a small number of input traffic streams is appropriate considering the emergence of Voice over IP (VoIP) that is now ubiquitous in Enterprise networks. It is suggested in the literature that VoIP switches designed to cater for small/medium-sized enterprises (SME) may have as few as 8 input traffic streams [VEGA2000]. These new small switches illustrate a shift in the design of some access networks, from large routers/switches catering for as many as 30,000 users. This thesis acknowledges this change in network design and develops a new expression for the buffer overflow probability, suitable for the analysis of local Internet/enterprise networking multiplexers. The new expression builds on a previously published analytical approach that uses discrete time, excess-rate queuing theory to produce closed form results for delay distributions. The examination of small Enterprise multiplexers is supported by an extensive set of packet-level simulation results which extends the analysis to an end-to-end delay study through a series of queues, which has a wide application in VoIP networks. The results obtained through the new expression are used, in conjunction with an analytical approach based on convolution, to accurately predict the end-to-end delay distribution in small-to-medium (enterprise style) networks. The new method has application in the dimensioning of Service Level Agreements (SLAs) in VoIP networks and for planning and provisioning of service partitions in IP packet switched networks. The advantage of the new expression over a previously