From: Joerg Micheel (joerg@cs.waikato.ac.nz)
Date: Mon Jan 08 2001 - 21:55:31 PST
The Passive Measurement and Analysis (PMA) team of NLANR MOAT at SDSC/UCSD
invites Internet researchers to discuss the next generation of passive
network measurements to be carried out in the High Performance (HPC)
backbone networks.
Since 1995 the National Laboratory for Applied Network Research (NLANR)
has been collecting IP packet header traces to support research in
understanding the systemic nature of the Internet. The 12 sites chosen
for capturing traffic traces are located at high-bandwidth interconnection
points, typically access links from GigaPops to the vBNS core. The
measurement strategy was defined as samples captured eight times a day
for a defined length of time. Initially, this sampling interval was
set to 2 minutes, today it is 90 seconds. The reason for the change was
to limit the amount of data being captured per day. Today, the system
collects between 1.5 and 3.2 Gigabytes of compressed data per day. The
Network Analysis Infrastructure maintained by the MOAT team is designed
as a service to the research public and allows for WWW access to all of
the data being collected. The Datacube is an interface to search and
browse trace data for specific metrics without having to download the
large trace data files for detailed analysis.
Initially, the data collect systems (OC3MON) were based on inexpensive
commodity hardware (PC's with FORE ATM NICs). Experience with those
systems has highlighted some of the shortcomings in deploying standard
network interface cards. NLANR has been vital in supporting the development
of dedicated passive network measurement gear. As a result, the recent
monitors in the PMA infrastructure support high-precision timestamping,
syncronization of both cards for bidirectional capturing, OC3c and OC12c
links with ATM and PoS encapsulation and the capability to syncronize
to an external clock source, such as a GPS or CDMA time receiver.
At the moment, the PMA team is busy placing the remaining dozen of new
monitors at important points of the Internet2/Abilene network. From our
point of view, it has become crucial to understand the kinds of analysis
that is being done with the data captured in order to develop better
monitor placement strategies and trace schedules. With the previous set
of monitors the placement strategy was determined to provide a good
coverage of the overall network, so each monitor captures a unique
portion of the overall network data. With the new set of 25 monitors
available a more dense instrumentation of the network has become feasible.
This means that the same traffic flow can be observed at multiple
measurement points and the distortion of the traffic pattern can be
studied. A correlation between the data captured at one point in the
network with data captured at a different point should become possible.
We are looking into providing different kinds of studies, such as long
traces (hours, even days or weeks). We are planning to provide more
detailed postprocessing (different sets of graphs) along with the traces
published. At the same time, the group is seeking to reduce the amount
of management overhead for maintaining the monitors and the data collection
postprocessing. This implies changes to the trace schedules to somehow
balance the amount of data collected.
We are seeking your constructive discussion on the following topics:
o focus of your research in the area of passive measurement analysis
and consequently:
o monitor placement strategies
o trace durations and trace schedules
o trace postprocessing and WWW publishing
o trace scenarios (router instrumentation, cross-US, transatlantic, ...)
o trace variety (LAN views, WAN access view, backbone view)
o any other passive measurement topics that you find appropriate
Your contributions should be send to the Internet Trace User Community
mailing list at <traces@nlanr.net>. We are looking forward to your mail.
For the NLANR PMA team
Hans-Werner Braun, Principal Investigator, NLANR MOAT
Joerg Micheel, PMA team leader
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References
NLANR MOAT: http://moat.nlanr.net/
WWW access to traces: http://moat.nlanr.net/Traces/Traces/
Datacube: http://moat.nlanr.net/PMA/Datacube.html
Subscription
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Hans-Werner Braun <hwb@nlanr.net>.
This article is also going to appear in the Network Analysis Times,
Volume 2, Issue 1 (scheduled for publication by the end of January):
http://moat.nlanr.net/NATimes/NAT.2.1/index.html
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