Capacity planning , transit vs last mile

Jean-Francois Mezei jfmezei_nanog at
Thu Mar 31 06:51:00 UTC 2016

Canada is to hold a 3 week long hearing on discussing whether the
internet is important and whether the farcical 5/1 speed promoted by the
government is adequate.

In this day and age, it would be easy to just set FTTP as target
technology and be done with it, but too many want to have a policy that
is technologically neutral.

To this end, I will not only be proposing that subsidized deployments
not only meet advertised service speed standards, but also a capacity
per end user metric for the last mile technology  as well as for the

(One of the often subsidized companies deploys fixed wireless which
delivers the advertised speed for the first week, but routinely gets
oversubscribed after a while and customers feel like on dialup.)

I know that for sufficiently large ISPs, they currently provision just
over 1mbps of transit capacity per end user (so 800-1000 customers per
1gbps of transit). The number rises by over 30% a year as usage grows.
(The CRTC can get exact figure from telecom operators and generate
aggregate industry-wide growth in traffic to do yearly standard adjustment).


Say the policy is 1mbps per customer if 1000 customer or more.  Is there
some formula (approx or precise) to calculate how that 1mbps changes for
smaller samples ? (like 500 customers, 200 ? )

And on the last mile portion where one has typically few users on each
shared capacity segment (fixed wireless, FTTP, cable), are there fairly
standard oversubscription ratios based on average service speed that is
sold in that neighbourhood ? (for instance if I have 100 customers with
average subscibed speed of 15mbps, how much capacity should the antenna
serving those customers have ?

I realise that each ISP guards its oversubscription ratios as very
proprietary, but aren't there generic industry-wide recommendations ? My
goal is to have some basic standards that prevent gross over
subscription that result in unusable service.

As well, I want that a company pitching a broadband deployment be able
to demonstrate that the technology being deployed will last X years
because it has sufficient capacity to handle the number  of customers as
well as the predicted growth in usage each year.

Any help ? comments on whether this is crazy ? sanity check ?

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