Initial Route Server Stats for MAE-East

William B. Norton wbn at
Mon Oct 23 15:59:24 UTC 1995

Once last set of comments.   Mike asks what is the measurement for?  When 
BGP sessions break it is sometimes because of partial or complete packet 
loss.  I think some goals here include:

1) we want to be able to correlate BGP session failures with packet loss, 
2) we would like to understand how the NAP performance contributes to
routing stability.

It is interesting to note that some interesting correlations result as a 
side effect.  Specifically, the strong correlation between packet loss 
and gigaswitch utilization, and packet delay and gigaswitch utilization.  
Not perfect correlation, but somewhat strong.

PS - 
Dun & I did some further data analysis and calculated that 1% of the packet 
loss can be attributed to the last of 5 packets (20%) transmitted having
a response time of greater than a second (which occurs 5%-10% of the time).  
That is, the last packet response doesn't come back in the 1 second 
timeout period and stats show this as a loss.  The first four packets can 
have delays > 1 second, but the last can not.  We can attribute 
approx. 1%-2% of the packet loss to this phenomenon.


On Sun, 22 Oct 1995, Mike O'Dell wrote:
> sorry if this seems so trivially obvious, but depending on what you are
> trying to measure, sources of significant signal noise *is* one thing
> to consider when doing an experimental design.  using Pings to cisco
> routers produces a signal with a number of different components, some
> real signal, some noise, depending on what you you are trying to
> measure.

William B. Norton			Merit Network Inc.
e-mail: wbn at			phone: (313) 936-2656

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