[AG-TECH] packets dropped on the minute

[Robert Olson]

the periodic packet loss is an indicator of misconfigured multicast routing 
somewhere along the line;  I don't know offhand specifically what may cause 
it but the network folks may (bill?)

--bob

At 01:03 PM 2/18/2003 -0500, Gurcharan S. Khanna wrote:
>hi,
>
>we have had and continue to have similar problems. it seems
>related to how many bits we're pushing out--the more bits the
>greater the packet loss. seems like anytime we go over 2-2.5Mbps
>we start to see increasing packet loss. and increasing distortion
>in the audio especially.
>
>we have had some recent network hardware upgrades and don't
>notice this as much now, but it still seems an unknown cause.
>
>our networking people don't see this loss at all--but then maybe
>they wouldn't be expected to???
>
>all our traffic goes through a packetshaper, but they've played with
>that without any seeming improvement.
>
>our beacon seems to indicated a mixed picture--ok to some sites,
>bad to others, and in some cases it says we're not even seeing ourselves!
>
>i'd be very interested in possible causes and tools for diagnosing/
>confirming this behavior.
>
>thanks,
>===========================
>Gurcharan S. Khanna, Associate Director
>Research Computing, Dartmouth College
>gkhanna at dartmouth.edu
>office: 603-646-1644
>http://research.dartmouth.edu/
>http://www.dartmouth.edu/~gkhanna
>
>-gurcharan
>--- Andrew Shewmaker` wrote:
>Hi,
>
>Now that we have used our AG node to attend a few events,
>we have most everything working well.  We did notice that
>every minute on the minute we lose packets on our display,
>audio, and video hosts.
>
>We are positive that we aren't seeing the packets at all
>because we can see with the MS Windows 2000 cpu monitor
>a huge drop in load, and then a resumption of the previous
>load.  Since there isn't a spike, that seems to indicate
>that the packets aren't suddenly coming through all at once.
>
>It almost makes the audio unusable...at the very least it
>seems to strike whenever someone says something interesting.
>
>Our networking people are trying to discover what is
>happening, but they don't have any likely suspects.
>
>Has anyone else seen something like this?  Can you help us
>fix this?  This is a significant quality issue for us.
>
>Thanks,
>
>Andrew
>
>--
>Andrew Shewmaker
>Associate Engineer
>Phone:  208.526.1415
>Fax:  208.526.4017
>
>Idaho National Engineering and Environmental Laboratory
>2525 Fremont Ave.
>Idaho Falls, ID 83415-3605
>--- end of quote ---