The University of Saskatchewan campus covers a large physical area: with more than 40 buildings distributed over 147 hectares of land on the banks of the South Saskatchewn River. Our geography .has a significant impact on our approach to delivery of IT. The campus wireless network is one of several new projects we have recently introduced to enhance the computing environment for our 18:000 students. Our approach is to provide mobile users vith access to our wireline network through high-speed wireless access points located in very public areas. Our initial deployment began in the 200li02 academic year with a small number of Cisco access points (18) placed strategically in a number of locations. The demand for wireless access .continues to grow;_ and the network is being expanded to offer higher capacih and greater coverage to the campus. In order for us; to plan for this expansion, it is important that we understand current usage patternsthat we understand where, when: horn much, and for what our wireless network is currently being used. This paper describes the methodology we employed to collect data on usage: and presents the results of our analysis. Although our wireless nehvork is small at the present .time, a description of our approach to this analysis will be useful to others planning similar studies. Usage data i v z collected in co-operation with our Information Technology Services Division (ITS) over the period of one week in January 2003. Although no effort was made to ensure this week was representative of overall usage patterns, we feel that the data we collected represents a uschl snapshot of the usage of a campus wireless nehvork. The paper is organized as follows. Section 11 reviews related work in wireless network measurement. A brief description of the wireless network in place at the time of our data collection follows in Section 111. In Section IV we describe the methodology followed when gathering and analysing the data, including steps taken to ensure user confidentiality Section V contains the results of our analysis. We conclude in Section VI with a summary of our findings. The design of this experiment was based largely on work done by Balachandran et nl. [I]. Their analysis and charactenzation of the traffic generated by attendees of an ACM conference provided many useful insights. They employed two mechanisms to gather wireless traffic traces during the conference. One trace was gathered by periodically polling each of four access points positioned in the conference hall with SNMP requests. This trace revealed usage statistics at the access-point level, including the number of users currently connected. and the number of transmission errors. The second trace was gathered at a router that connected the access points to the campus netnork. This trace was done using tcpdump to gather anonJmised TCP packet headers. The analysis of those headers revealed access-point independent statistics, such as the total amount of traffic on the wireless nehvork and the application mix of that traffic. Although the conference trace was gathered successfully and analysed thoroughly: the findings from its analysis have limited applicability to a full campus setting. The conference had a set schedule, which caused readily apparent traffic patterns as all attendees moved from event to event. Furthermore, the access points were all placed in the same conference hall area: which resulted in almost identical usage patterns being observed at each access point. The analysis of the Dartmouth College wireless network by Kotz and Essien [ 2 ] is more relevant to campus-wide net\\-orks. Dartmouths wireless nehvork is made up of 476 access points providing coverage in 161 buildings for almost 2000 users. The Dartmouth study used a combination of three forms of tracegathering: event-triggered log messages, SNMP polling 07803-8355-9/04/S20.M) @22004 IEEE. 862
In REF the authors present a study in which a small, but carefully designed, WLAN was used to investigate the usage of the network before an expansion plan was drawn.
Characterising the use of a campus wireless network
IEEE INFOCOM 2004
IEEE INFOCOM 2004
Computer Science