Download Network Troubleshooting from End-Hosts

Abstract
Troubleshooting faults or performance disruptions in today’s Internet is at best frustrating.
When users experience performance or connectivity problems, there is little they can do.
The most common attempt to solve the problem is to reboot or call the provider’s hot line.
Network providers have more information to use in diagnosing problems in their networks,
but their network troubleshooting is often mostly manual and ad-hoc. We argue that
automatically troubleshooting network faults or performance disruptions requires monitoring capabilities deployed at end-hosts (in or close to the customer’s premises). End-host
monitoring is necessary to detect the problems that affect end-users. In addition, when
problems happen outside the control of the network administrator or the end-user performing the troubleshooting, end-host monitoring is the only approach to identify problem
location. The goal of our research is to make network troubleshooting more transparent by
designing tools that require as little as possible human involvement (both end-users and
administrators).
This document presents our initial steps towards automatic network troubleshooting
from end-hosts as well as our long-term objectives. Our main contributions are the design
of more accurate and efficient end-host measurement methods. We work both on techniques to detect faults and performance disruptions, and to identify the location of the
problem. For fault identification, we improve the two basic techniques using end-to-end
measurements: traceroute and network tomography. First, we show that traceroute, the
most widely used diagnosis tool, reports erroneous paths in the presence of routers that
perform load balancing. We build Paris traceroute to correct these errors. Second, we
design measurement methods for accurate fault identification using network tomography.
Network tomography assumes up-to-date and correlated measurements of the status of endto-end paths and of the network topology, which are hard to get in practice. We design
techniques to track correlated path reachability and network topology. Finally, we design
techniques for lightweight detection of faults and performance disruptions. We minimize
the overhead of active end-to-end probing for fault detection and design a tool to collect
passive measurements at end-hosts.
Key Words:
Network troubleshooting, network performance diagnosis, network tomography, traceroute,
network topology measurements, end-host data collection
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