Classification of Access Network Types Ethernet Wireless LAN

Classification of Access Network Types: Ethernet, Wireless LAN, ADSL, Cable Modem or Dialup? Wei, Bing Wang, Chun Zhang, Jim Kurose, Don Towsley University of Massachusetts, Amherst Department of Computer Science Presented by Mark Johnson Advanced Computer Networks

Introduction • Classify Access Network Type – Ethernet (switched and not) – WLAN – ADSL – Cable Modem – Dialup • Accurate, fast classification from external location Advanced Computer Networks

Background • 802. 11 b Standard WLAN – Average transmission overhead of 810 ms – Wireless station must wait for random backoff • DOCSIS (Cable modem) – Backoff to send request • Ethernet, ADSL, and dialup – Dedicated access, no backoff Advanced Computer Networks

Classification Scheme • Two primary measures – Inter-arrival time – Entropy • Method – Send n packet pairs – Calculate population median inter-arrival ξ. 5(I) – Calculate entropies and Advanced Computer Networks

Classification Scheme Advanced Computer Networks

Analytical Basis • Assumptions – Up to two low bandwidth links – M/D/1 queuing – Interarrival times at receiver are indicative of interdeparture times at sender • Theorems – Ethernet median and entropy – 802. 11 b median and entropy – ADSL, Cable, and Dialup median and entropy Advanced Computer Networks

Experimental Results • Controlled Experiments (small scale) – Detection on known University and home connections – Results mainly as expected: median and entropies of inter-arrival times fit models Advanced Computer Networks

Experimental Results Advanced Computer Networks

Experimental Results • Uncontrolled Experiments (large scale) – Bandwidth of receiver isn’t important – Results largely fit expected demarcations • 5 DSL connections would erroneously be detected as WLANs – Criteria for distinguishing low bandwidth connections are not clear Advanced Computer Networks

Experimental Results Advanced Computer Networks

Experimental Results • Combination of mean and entropy gives a good classification • Distinguishing low speed (ADSL, Cable, dialup) connections is not straightforward • Connections with a large median usually have a large entropy Advanced Computer Networks