Computer Communication Networks: Approaches, Objectives, and Performance Considerations
ACM Computing Surveys (CSUR)
Online system performance measurements with software and hybrid monitors
SOSP '73 Proceedings of the fourth ACM symposium on Operating system principles
| Hi-index | 0.00 |
This paper describes a program which utilizes a discrete event simulation to drive a real switching node. Empirical measurements of various nodal performance characteristics are gathered and recorded during the exercise of this program to aid in the evaluation and design of candidate future nodal architectures. Applications software and specialized hardware for a unified node which switches both digitized voice and data (packet) traffic were developed and tested in a flexible testbed facility at RCA in Camden, New Jersey. Both voice and data traffic are switched over common trunking facilities employing dynamic channel allocation. All packet transfers are made under the protocol set forth by the ANSI Advanced Data Communication Control Procedures (ADCCP). To measure the performance characteristics of the unified switching node, software was developed to simulate the node/network and node/source terminal interfaces. Projected levels of voice and packet traffic were used as inputs to a discrete event simulation program which generates a source traffic tape in accordance with specified interarrival and holding time distributions. This traffic tape then serves as the traffic input to the network simulator software which examines and interprets each traffic event on the tape. The network simulation software reacts to data arrivals by generating properly formatted packets, introducing these packets to the nodal applications program at the appropriate times, and providing all required network and source terminal protocol responses. Voice call arrival and departure events are used to alter the packet service rate on those trunks which employ dynamic channel allocation. Performance statistics and measurements are continuously collected by the network simulator and prepared for analysis by off-line data reduction programs.