Performance analysis of an ATM-based local area network

In this paper, we report on how we conducted a detailed analysis of a very large corporate ATM backbone network. The performance analysis tasks were conducted in three stages: call route analysis, traffic flow analysis and network performance analysis. The call route analysis was to determine if the routes from the edge switch to the core switch took the optimal path. This analysis revealed several sub-optimal routes for the IISP protocol configuration. The traffic flow analysis is based on the need for traffic to flow from one ELAN to another ELAN through a virtual router. The analysis showed that several routes require additional hops to reach their respective primary and secondary routers. The performance analysis was conducted using the data collected through the SNMP management system for a two month period. By using several statistical analytical methods, the high utilization segments in the edge networks as well as in the core networks were identified. The results showed that the LAN segment can accommodate two times more bandwidth for the currently shared network users, and can accommodate 50% more traffic when these users are migrated to the switched ports. For outer cores, the current utilization remained at 20%, i.e., four times more than the current traffic can be handled. Finally, the inner core traffic stayed at about 16% of the network utilization for 80% of the time. This analysis demonstrated a systematic method of demonstrating current network utilization to the network manager for current network operation and future growth planning.