links on the blink (fwd)

Michael Dillon michael at
Thu Nov 9 07:02:13 UTC 1995

On Wed, 8 Nov 1995, Dennis Ferguson wrote:

> > I just have a memory which is good at storing facts. Sometime in the last 
> > month on either nanog or com-priv a person whose name escapes me posted 

> Oh, man, this is getting so silly I can hardly bear to look in my
> mail box.  If you'd wanted to name someone who'd been recently working
> at measuring and statistically characterizing Internet traffic you could
> have just cut-and-pasted the name on the top line of your note, 

Didn't I say I can't remember the name? Didn't I say I am not an expert 
in this field of endeavor? 

> who you
> contradicted on a related point of fact based on something you half-remember
> reading in com-priv.

Somebody else was kind enough to point me to a WWW site that covers some 
of the work that HWB and k claffy have done. In a paper which they posted 
on the web, I found this statement:

    For example, one characteristic of network workload is `burstiness',
    which reflects variance in traffic rate. Network behavioral patterns of
    burstiness are important for defining, evaluating, and verifying service
    specifications, but there is not yet agreement in the Internet community
    on the best metrics to define burstiness. Several researchers [21,22,6]
    have explored the failure of Poisson models to adequately 
    characterize the burstiness of both local and wide area Internet 

This is precisely the item that I am focussing on because I believe it 
partially explains why service is not improving. I also believe that if 
Internet traffic continues to have this non-Poisson characteristic then 
the efforts of NSP's to maintain high service levels will not be 
as effective as might be expected. Although I don't know whether telco 
POTS service exhibits Poisson characteristics, I suspect that it doesn't 
and plays a large part in helping them maintain near perfect service levels.

At the time I first read of this discovery, I filed away the information 
because I felt it was useful in helping my customers understand why 
sometimes the Internet works fast for them and sometimes it is jerky and 

So, is this right or wrong? Does this non-Poisson characteristic explain
why the network performance tends to be erratic? Or is it a minor factor 
not worth worrying about (operationally) at the present time?

Michael Dillon                                    Voice: +1-604-546-8022
Memra Software Inc.                                 Fax: +1-604-542-4130                             E-mail: michael at

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