**** Columbia Network Research Group Seminar ****

Title:    Trajectory sampling for direct traffic observation
Speaker:  Matt Grossglauser (joint work with Nick Duffield)
          AT&T Research
When:     November 22, 2000 - 10 am
Where:    Interschool Lab, CEPSR Building, 7th floor
          Columbia University

Abstract:

Traffic measurement is a critical component for the control and
engineering of communication networks.  We argue that traffic
measurement should make it possible to obtain the spatial flow of
traffic through the domain, i.e., the paths followed by packets between
any ingress and egress point of the domain.  Most resource allocation
and capacity planning tasks can benefit from such information.  Also,
traffic measurements should be obtained without a routing model and
without knowledge of network state.  This allows the traffic measurement
process to be resilient to network failures and state uncertainty. 

We propose a method that allows the direct inference of traffic flows
through a domain by observing the trajectories of a subset of all
packets traversing the network.  The key advantages of the method are
that (i) it does not rely on routing state, (ii) its implementation cost
is small, and (iii) the measurement reporting traffic is modest and can
be controlled precisely.  The key idea of the method is to sample
packets based on a hash function computed over the packet content. 
Using the same hash function will yield the same sample set of packets
in the entire domain, and enables us to reconstruct packet trajectories. 

Biography:

Matt Grossglauser is a member of the Networking and Distributed Systems
Laboratory at AT&T Labs - Research.  His research interests are in
network traffic measurement and modeling, resource allocation, network
management, and mobile communications.  He received the Diplôme
d'Ingénieur en Systèmes de Communication from the Swiss Federal
Institute of Technology (EPFL) in 1994, the M.Sc.  degree from the
Georgia Institute of Technology, in 1994, and the Ph.D.  from the
University of Paris VI in 1998.  He did most of his thesis work at INRIA
Sophia Antipolis, France.  For his thesis work, he received the 1998 Cor
Baayen Award from the European Research Consortium for Informatics and
Mathematics (ERCIM).