[LINK] NBN is FTTH
pbrooks-link at layer10.com.au
Wed Apr 8 10:02:54 AEST 2009
Jan Whitaker wrote:
> At 11:09 PM 7/04/2009, Paul Brooks wrote:
>> Now try to imagine the backhaul required to service the head-end if
>> 5000-10000 users are hanging off the head-end with 10Gig dedicated links
> What are the implications for the offshore connectivity? Or is that
> what you're referring to?
I was referring to just the local backhaul link feeding data from the
service provider's core network to the head-end (I hesitate to use the
word 'exchange', as it might not be at an exchange as we understand the
term now) of the access network - however the same consideration applies
to international connectivity, at least while the same ratio of
local:international data transfer is maintained.
I do however think the apparent 'shortage' of international capacity is
a misconception at the moment. The issue is generally not any limit on
capacity - there's plenty of un-utilised bandwidth on some of the
international cables - the issue currently is the high price, that
encourages the providers that buy justa little too little capacity to
run the links into congestion and then some before adding incremental
capacity, to manage the costs so as to keep the performance just under
the 'scream point' of their customer base.
ALso, many people do not appreciate the effects of the
bandwidth-delay-product and the receiver window size that underlies the
Internet protocols. Even if you were the only person on the planet
passing traffic along an otherwise empty international cable, you may
not see any increase in the data transfer rate from a far away site with
a long round-trip-delay between you and the site. More long-haul
capacity doesn't necessarily imply faster downloads, it just allows more
people to transfer data in parallel with you before the system clags up.
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