Campuses:

Applications of network spectroscopy

Wednesday, January 14, 2004 - 9:30am - 10:20am
Keller 3-180
Andre Broido (University of California, San Diego)
Interpretation of spectra is practiced since Noah's time. Quantum mechanics, chemistry, geophysics and communication owe it many of their successes. Spectroscopy paradigm is now becoming popular among Internet scientists. Properties of sources, links and switches (e.g. Layer 2 techologies, link bitrates, paths, OSes) can be inferred from periods and quantizations of packet timings and header fields. Network conditions from traffic congestion to DDoS attacks are studied with these and related techniques of spectral analysis.

In this talk, we give an overview of results obtained by other groups working in the field. We then describe two applications that identify network properties via delay spectra. In one case, we prove that spurious DNS updates at root and blackhole servers come from the Microsoft Win2000 DNS implementation. The method is based on a binary autocorrelation of interarrival times. In another case, we apply spectroscopy to the bitrate estimation of an end-user access in DSL and cable infrastructures. We use entropy minimization for Radon transformed marginals of the delay distributions and packet arrival times and find delay quanta that identify provisioned bitrates.
This is a joint work with Evi Nemeth, Ryan King, and K.C. Claffy