Possible New Sites
We advised the International Atomic Energy Authority
on use of the PingER software to
monitor links of interest to them
and collaborators in Brazil. For a short time it appeared they
might come on board
and contribute to the HEP monitoring, but we haven't heard from
them for a few weeks.
We also received an enquiry from the Greek National Network Center
and from an ISP in the Philipines about
Our work with the Cross Industry Working Group is proceeding. They recently
added a new monitoring site ( http://mason.cnri.reston.va.us ).
Warren and Les are preparing talks to present to the group early in February.
Attended a voice conference with the XIWT/IPERF group. The main topic was
a presentation by NIST on how correlated ping measurements from a to b
ping measurements from b to a. In the short term seconds to several
minutes there seems to be only moderate correlation.
We had a voice conference with Becca Nitzan and Mike Collins of ESnet
to discuss QoS measurements and preference bit settings.
Later had a face to face meeting to go over how to collaborate on
DiffServ experiments and measurements.
Followed up on a request from the ESSC International working group to
add 4 more Beacon sites to the ESnet/HENP monitoring. Sent email to
contacts at the 4 sites requesting a suitable host to monitor. So far,
only one of the sites has responded.
In response to a question from a user, we looked at the change in
response time between SLAC and KEK following re-routing of the link via the
Chicago STAR-TAP. The round trip response time has gone up by between 50 and
Starting to work with NetPredict on a
possible phase II SBIR.
Followed up on the status of the Technology Transfer
proposal Charley Graneieri and Les worked on in the Fall of last year.
The Lab directors favor funding this, but it
now needs updating since it was written
about 6 months ago.
Stanford Computer Science Department
Arranged to give a Stanford Networking Seminar on Internet
end-to-end performance in the Gates building on March 4th
Met with person on campus to coordinate. The abstract is available at
regarding the analysis scripts we have developed.
Warren began work on a tool to aid with the configuration of the programs
in the PingER package. The tool uses the Perl/Tk perl module.
for a screenshot.
Last month we put a machine outside the SLAC firewall
and behind a router running Cisco test code that allows setting
precedence bits. This is to enable tesing the effect of
setting precedence headers of ping requests sent to a specific host at CERN.
The machine we used for the monitoring turned out to have
faulty network chip, so Warren disabled the built in NIC,
and installed and configured a new NIC
card. Using this we were successfully able to send pings with precedence bits
We verified that the precedence bits were set by using a sniffer to look
at the packets. Following this we made measurements for about a week to
compare ping performance with and without precedence bits set on the path
SLAC and CERN. This path gets utilization up to about 50% but the results
showed no impact of setting the precedence bits. Communicated with
Denise Heagerty of CERN concerning setting the precedence bits in the
Also working with ESnet to set up an ATM PVC between SLAC & LBNL. We will use
this to measure the effects of adding congestion and setting precedence bits
on the performance of the link for pings, VoIP and video.
Analzed the ESnet bytes accepted reports to provide long term utilization
charts for Walter Toki to present at the ESSC.
Christmas Glitches, BNL down
Around Christmas, several monitoring sites suffered glitches and Warren had to
a lot of his time to finding out the status from the local administrator
pushing them to get things back and running. Warren wrote a
to help us to keep track of gathering data. Fortunately we were able to
much of the missing data from these glitches,
although BNL has been down for much of January
due to a security issue.
We spoke to ESnet's Michael Collins about anomilies
we were observing in routing. He
provided us with useful information and Warren adapted
his network snapshot program to
look at network numbers and AS's rather than just the IP number.
Warren has applied the
work to produce
snapshot of the network between the XIWT sites.
Validating use of ping
Did some more work on understanding how
TCP throughput is related to
loss and round trip delay.
2 ways to measure ping "jitter" and
compared them to show there is little difference.
compared one and two way jitter using Surveyor and PingER data.
Sent email to Surveyor folks & Vern Paxson soliciting input. Got a response
Internet Monitoring Tutorial to extend the table of contents,
add new sections on the extent of the PingER projects (including the XIWT),
the architecture, to provide information on the
global and affinity distributions of the ~ 1100 PingER monitor-site and
remote-sites, and provide a lot more information on jitter (comparisons
of various ways of calculating it, comparing one and two way jitter).
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Revised 23 January 1999