[LINK] Congestion (was Re: NBN to cost 24 times South Korea'sfaster network, says research body)

Jamie Sunderland Jamie.Sunderland at aarnet.edu.au
Fri Feb 11 11:38:01 AEDT 2011

Hi all,

>From my POV - Wireless has a technical limitation that can cause some
levels of congestion (related to collision domains, cell size and
available spectrum).

The fibre network proposed by NBN will have some business model
limitations that will cause some levels on congestion.

What most people overlook is that the NBN is not just a GPON network to
a CPOI.... in most cases it will actually be..


Or in NBN speak

AVC=Access virtual Circuit
CVC=Connectivity Virtual Circuit
NNI= Network to Network Interface

The CVC is a point of aggregation, and individual ISPs can decide (based
on their own business models) how much they want to over-subscribe the
CVC. Although pricing models are still being developed, for the first
release sites the wholesale cost of a 100/40 AVC is about $38/month,
however a 100Mbps CVC is about $2000 per month. Carriers without their
own fibre into the POI will also have to buy backhaul from a provider
such as Telstra, Optus, Nextgen or PIPE to get the traffic back to their
PoP. In many cases (depending on location) this will be at least as much
as the CVC again.

So for an ISP to sell a 100/40 service at less than about $60-$70/month
- they would have to over-subscribe the CVC and the backhaul at a rate
of around 200:1.  Some of the large carriers with their own backhaul
will have an advantage here (which is why they pushed for more POI
locations) - and some "budget" ISPs will massively oversubscribe their
CVC and backhaul components.

This is why there is going to be multiple traffic class options that
will attract some significant extra premiums.  Real business grade
services may still be of the order of 5-20 times the cost of a
residential service - depending on the traffic class and contention
ratios you are prepared to accept.

Just some food for thought.

Reference: NBN Product and pricing guide http://tinyurl.com/4oodv8g


-----Original Message-----
From: link-bounces at mailman.anu.edu.au
[mailto:link-bounces at mailman.anu.edu.au] On Behalf Of Stilgherrian
Sent: Friday, 11 February 2011 11:23 AM
To: Link list
Subject: Re: [LINK] Congestion (was Re: NBN to cost 24 times South
Korea'sfaster network, says research body)

On 11/02/2011, at 11:07 AM, Paul Brooks wrote:
> Yes, with fixed wireless the operator has a similar level of visibilty
and control,
> and provided they don't overbook the capacity there should be no
> Unfortunately the capacity of a wireless tower is likely to become
filled more
> quickly, so the refusal to set up new services once the available
bandwidth is all
> reserved could be interpreted as a form of congestion. The operator
would call this
> 'admission control'.

The other issue is that even if the number of connections per fixed
wireless cell is pre-determined, if that number is "everyone" -- as it
would be if wireless is providing "the" national broadband CAN -- then
you either end up with a lot of slow connections per cell or very
closely-spaced cells indeed.

Network engineering consultant Narelle Clark has done some spectrum
modelling. She reckons that to deliver the same speeds that you get from
wired links you'd need to have a base station at the end of every
suburban street.

Crikey article: "Coalition broadband: a wireless tower in every street"

"Patch Monday" podcast: "Understanding the broadband election"


Stilgherrian http://stilgherrian.com/
Internet, IT and Media Consulting, Sydney, Australia
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