Standards for last mile performance

Jean-Francois Mezei jfmezei_nanog at
Sat Apr 30 16:25:52 UTC 2016

The CRTC hearing went well (thanks for all your help).

One of the unanswered questions was how to set performance standards for
the last mile to ensure people get advertised speeds (within reason).

I had asked the question about contention ratio and it appears there is
no proper way to set such a moving target as a regulatory standard.

During the hearing, someone suggested that advertised speeds be
achievable 80% of the time. (chairman then asked if "time" was 24 hours,
or just the time you needed to use the internet (aka: peak).

Out of curiosity, could such a thing be measured by the last mile operator ?

There is the easy answer of synch. For DSL, non delivery of advertised
speed is easy since that metric is on the modem statistics. However, for
fixed wireless, would a customer too far from tower see a lower synch
rate or would he just see poor performance due to lots of retransmits ?

So some generic questions:

What are the different ways used to determine if the last mile is
congested and needs to be upgraded ?

>From the network operator's point of view, would it not be looking at 5
minute throughput samples and trigger upgrades when it sees throughput
reaching  x% of last mile segment capacity for more than X minutes per
day ?

What other means do network admins use to monitor when it is time to
upgrade shared last mile segments such as coax or fixed wireless ?

from a policy point of view, is it possible to set the same standard for
different technologies or should each (dsl, coax, fixed wireless and
satellite) have they own standards and methods of measurements before of
intrinsic differences in how they work ?

In the case of Rogers (canadian cableco), the CRTC record shows that
they trigger node split process when capacity reaches 60%. This is
because it takes them so long to do all the paperwork, committees etc
that by the time the node split is done, that segment has grown to about
75% utilisation.

Would that be a sound basis to set a policy ?

For shared last mile, would different technologies have similar
thresholds that trigger the need for upgrades or would coax start to
degrade at 75% whereas fixed wireless or satellite  start to degrade at
lower/higher number ?

For FTTP, while likely not a big problem yet, would similar number apply
when the ~2gbps download and ~1gbps upload start to get filled by the 32
homes served ?

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