Traffic Home 

                                                            

DATA COLLECTION METHODOLOGY

 

 

 
   
   
 

 

 

Traffic between the Internet and the University of Massachusetts Lowell (UML) network edge router flows through four T1 lines. The UML network is connected to the edge router through 100 Mbps fiber optic links. One of the ports on the router is dedicated to monitoring the uplink and downlink traffic. The packet header traces are obtained using the tcpdump utility. This utility captures to a file a summary of all the packets that traverse the network being monitored. The measurement location and data archive in relation to the UML network architecture is depicted in Fig. Data coming into and out of UML is forwarded to one of the ports on the UML Internet router. This monitoring port is connected to a hub. An optical transceiver is connected to the auxilliary interface (AUI) port of the hub and from here, a 100 Mbps optical cable carries the inbound and outbound traffic to the data collection and storage area. Traffic measurements are collected 24 hrs a day, seven days a week. The measurements of packet headers include timestamps at microsecond resolution, source and destination IP addresses, source and destination port numbers, packet size and protocol index. Traffic measurements are collected 24 hrs a day, seven days a week. The measurements of packet headers include timestamps at microsecond resolution, source and destination IP addresses, source and destination port numbers, packet size and protocol index. An example of the data trace is shown in the table below.

hour minute second microsecond source IP source port destination IP destination port packet size protocol
12 8 22 847145 129.63.88.12  80 24.36.122.112  6464 40 tcp
12 8 22 851876 24.36.122.112 6464 129.63.88.12 80 1500 tcp
12 8 22 855765 24.36.122.112 6464 129.63.88.12 80 1500 tcp

Daily and hourly trends in the traffic to and from the Internet are useful to determine the peak usage hours and the off-peak hours. The traffic characteristics are influenced by features such as the time-of-day, protocol, application ports, and packet sizes. To determine the influence of protocol, the number of packets and bytes generated were classified according to the protocol field.

Wireless Measurements