Title :
Wide area traffic: the failure of Poisson modeling
Author :
Paxson, Vern ; Floyd, Sally
Author_Institution :
Network Res. Group, California Univ., Berkeley, CA, USA
fDate :
6/1/1995 12:00:00 AM
Abstract :
Network arrivals are often modeled as Poisson processes for analytic simplicity, even though a number of traffic studies have shown that packet interarrivals are not exponentially distributed. We evaluate 24 wide area traces, investigating a number of wide area TCP arrival processes (session and connection arrivals, FTP data connection arrivals within FTP sessions, and TELNET packet arrivals) to determine the error introduced by modeling them using Poisson processes. We find that user-initiated TCP session arrivals, such as remote-login and file-transfer, are well-modeled as Poisson processes with fixed hourly rates, but that other connection arrivals deviate considerably from Poisson; that modeling TELNET packet interarrivals as exponential grievously underestimates the burstiness of TELNET traffic, but using the empirical Tcplib interarrivals preserves burstiness over many time scales; and that FTP data connection arrivals within FTP sessions come bunched into “connection bursts”, the largest of which are so large that they completely dominate FTP data traffic. Finally, we offer some results regarding how our findings relate to the possible self-similarity of wide area traffic
Keywords :
exponential distribution; packet switching; stochastic processes; telecommunication traffic; transport protocols; wide area networks; FTP data connection arrivals; Poisson modeling; Poisson processes; TCP arrival processes; TELNET packet arrivals; WAN; connection arrivals; connection bursts; exponential arrivals; file-transfer; modeling error; network arrivals; packet interarrivals; remote-login; self-similarity; session arrivals; time scales; traffic burstiness; wide are network; wide area traffic; Communication system traffic control; Electronic mail; Local area networks; Probability distribution; Routing; Scientific computing; Telecommunication traffic; Traffic control; Wide area networks;
Journal_Title :
Networking, IEEE/ACM Transactions on