[e2e] Queue size of routers

David P. Reed dpreed at reed.com
Tue Jan 21 06:51:45 PST 2003

At 09:09 AM 1/21/2003 -0500, RJ Atkinson wrote:
>        A more direct and proximal cause for the low probability of backbone
>link congestion is that most large ISPs deliberately over-engineer their
>backbones to have visibly more capacity than the max offered load.  No amount
>of flow smoothing could counteract congestion caused by an absence of
>over-provisioning of backbone links.

Just a thought about terminology that may confuse in this paragraph.

"max offered load" is correct, but some may read it as "max possible load" 
- I don't think most backbones are engineered to exceed any possible load 
that can be applied.  Instead real experience is used to determine what a 
peak load looks like.

"over-provisioning" and "over-engineering" should really be deprecated as 
terms because they sound negative, even unprofessional or inefficient.   In 
fact, the provisioning of extra capacity is one of the least expensive ways 
in most cases to achieve good quality of service (not QoS, but the ordinary 
lay understanding of that phrase).   We should reserve the terms 
over-engineering and over-provisioning to those cases where no user benefit 
accrues.   It is not "over-engineering" to deploy a 10 Mb/s Ethernet hub 
where the load on the network averages out to 50 kb/s, for example.

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