network problems

Rick Stevens stevens at
Wed Jun 23 19:49:37 CDT 1999

We should try pathchar and the active monitoring of the RTP losses for all
the streams
as we bring the AG nodes up.. and iterate until we understand the dynamics.. 
we should also get the netweather folks to monitor the nets we are using..

At 04:45 PM 6/23/99 , Kai Chen wrote:
>At 01:49 PM 6/23/99 -0500, Robert Olson wrote:
>>Off the top of my head, the statistics that I find myself wanting are
>>per-site, per-stream bandwidth/loss/latency/jitter statistics for the media
>>streams. This is information that can be gleaned from the RTP/RTCP headers
>>and sender/receiver reports. rtpmon provides some of this information, but
>>not all. 
>That's a very differnt requirement than the general network weather map.
>The current rtpmon forks off from vic/vat and monitors a single RTP
>session. Are you interested in monitoring ALL sesssions? It looks straight
>forward to run a daemon program which grabs all the sdr announcements, and
>taps into all the RTCP channels to gather information. Per-site monitoring
>is needed if you are interested in local RTP sessions (with small TTL).
>The rtpmon may not be doing this, but it seems to me that estimating the
>receiver bandwidth is possible just by looking and combining the sender
>reports and receiver reports. (RFC 1889 Session 6.3.4).
>>It would also be nice to be able to identify the critical paths
>>thru the network between sites, and the amount of bandwidth we are using on
>I haven't used it, but "pathchar" by Van Jacobson is the one that is close
>Kai Chen                Research Programmer
>217-265-4078            NLANR Application Support
>kchen at         NCSA - U of Illinois at Urbana-Champaign

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