[AusNOG] NBN and CVC

[Paul Brooks]

Back in the day*, one of the considerations in designing the NBN was avoiding the
costs of putting in a mother-of-all traffic monitoring and measurement system that
would retrieve and store usage data on all the 10+million endpoints. By keeping the
product suite a set of one-time-charge and fixed monthly values, no measurement was
required, the billing was kept simple, and periodic counter polling and associated
data reduction, processing, storage, and robustness of systems was avoided.
Clearly that has been superseded at least on the satellite links, where NBN are
tracking usage anyway.

Now you are talking about the CVC layer, not end-user, so theres a few orders of
magnitude reduction in polling and storage required to do traffic monitoring to
implement a p95 rating system just on CVCs - but the current system for all its faults
has the benefits that the costs and complexity of polling, calculating and billing on
usage are avoided, and billing disputes between RSPs and NBN are fairly binary with
the biggest possible area of contention being what date a billable element become
billable or not.

Also, for most PoIs, NBN switching to a p95 model of billing would require the
backhaul network transmission providers to also switch to a p95 model to become
effective. If the backhaul providers are selling transmission between capital-city and
POI in fixed increments that take 6 weeks to upgrade , then the NBN's charging model
is almost irrelevant, and the incentive to delay upgrading the backhaul transmission
retains the same problem.
In fact, its arguable how much of the congestion is caused by CVC and how much by
unwillingness to increase backhaul capacity to manage cost.

(*'Back in the day' means before the CVC/AVC and commercial structure was a twinkle in
someone's eye)

Paul.





On 30/07/2017 6:36 AM, Matthew Moyle-Croft wrote:
> Hi,
> So, feel free to shoot me here.  But curious for response either here or privately.  I don’t live in Australia but I still do care deeply about broadband in Oz having something to do with it for quite a few years.
>
> The big issue with NBN at the moment appears to be congestion related to the amount of CVC being purchased by ISPs.  The congestion is artificial because CVCs are bought, as I still understand it, in fixed amounts. (ie. we haven’t moved on from TW ADSL wholesale arrangements).
>
> Is buying the CVC in fixed amounts the right model?  What if it moved to a “transit” like p95 kind of model?  I get that there is some level of risk for the ISP that CVC cost could jump up a lot, but presumably it would be related to customer growth at a POI.  It might also allow connecting to new POIs where you have less customers.  I can see some guardrails around this - ie. a maximum amount maybe per POI? 
>
> At least if you were smart about this it’d allow ISPs to avoid congestion as customer bases are growing as more houses are onboarded.
>
> Given the nature of users I don’t think a p95 number could be gamed particularly, but it would ease some of the peaks a bit. 
>
> Thoughts?
>
> MMC
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