[e2e] Question about propagation and queuing delays

Randy Bush randy at psg.com
Mon Aug 22 23:40:13 PDT 2005

> In large fiber backbones, within the backbone we generally run 10:1  
> overprovisioned or more.

while i am quite ready to believe that in the backbones that you
run, this is the case.  in the backbones which are run by the large
and medium isps, this is not.  in the real world, it's driven by
provisioning time.  i.e., if one can provision in a matter of weeks,
then traffic usually grows sufficiently slowly that utilization of
well over 50% can be tolerated.  in the more realistic situation
where provisioning takes months, 50-66% is more the norm.  but as
i said, it also depends on rate of traffic growth.

> The people on NANOG and the people in the NRENs live in a certain  
> ivory tower, and have little patience with those who don't. They also  
> measure the world in a certain way that is easy for them.

unfortunately, what is 'easy' is that which is provided by the
broken vendor(s).  these tools are so gross as to only be useful
when the law of large numbers is in play in highly aggregated
traffic.  when small spiky flows are at issue, we're left in what
i might term as dirt, not an ivory tower.


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