Performance Analysis of WWW-Tra c over Multi-Ring DQDB Networks

We present a simulation study of WWW traac over multi-ring DQDB networks running the TCP/IP protocol stack. One-ring DQDB network is extended into two multi-ring structures and simulated. All network and protocol elements have been implemented in detail. Our traac source model and its parameters has been chosen according to the characteristics of typical WWW traac. The measurements have been made in several protocol layers in all investigated network models (DQDB and TCP throughput, losses and transmission delays). We have observed also the satisfaction of guaranteed QoS parameters at protocol layer 3 in the network models. The division into multi-ring structures improves in some way the network performances at the layer 3. However, the performances decreases very signiicant in case of router failure and they are worse than in one-ring structure. This problem can be solved with the usage of redundant routers in multi-ring structures. The division of one-ring network has a small innuence at the application layer. The performance at this protocol layer doesn't change signiicant and remains good.