What Speed Will We Get From the NBN?

I have just been reading an article on the capacity of the data cables going from Sydney through to Guam, and then on to the US. Currently it stands at 4Gb/s but with the new cable from Pipe Networks that should increase over time to 6Gb/s.

Trouble is that doesn’t stand up with a 100Mb/s NBN. When you look at the figures: –

The totally capacity coming into Australia when this is up to capacity will be 6Tb/s. The NBN will provide data connections at 100Mb/s or 0.1Gb/s. That means that just 60,000 connections at a full 100Mb/s, or assuming that maybe 20% of households are on the net at the same time connecting to the US (20% of 8.5M households is 1.7M connections) gives just 3.5Mb/s per connection.

Okay I know that there will be local caching, but this is going to need to be huge in order for us to see more than a connection at roughly the same speed as ADSL.

4 thoughts on “What Speed Will We Get From the NBN?”

  1. Dear Simon,

    Your numbers are way off mate….

    First off, from the Southern Cross Network site;

    “Southern Cross is currently delivering 295 gigabit/s of fully protected bandwidth and has the potential as demand growth requires to increase to 1.2 Tbps using the existing 10 Gbps technology or 4.8 Tbps using 40 Gbps.”

    So you’re kidding yourself with the 4/6 Gig call, I work for a small (compared to Telstra) transit provider and we’re already getting close to 4 gig.

    Secondly, try your maths again based on the 10-20 million estimated users in .au and the average speed of 1.5 meg, that’s 17.25 terabits you’d need, you quickly see that you don’t actually need to deliver full speed to consumer grade internet connections.

    And finally there is bugger all caching happening in the grand scheme of things, just a few tightarse ISP’s who use it.

    Hope that helps…..

    1. Don’t forget that I wrote this a while back! The Southern Cross site (http://www.southerncrosscables.com/public/home/whatsnewdetail.cfm?WhatsNewID=70) says that they are going to be doubling capacity to 1.24Tbps as you say from an existing 600 odd Gbps. The figures I used were from a press release on ITNews or CRN that gave the capacity of Pipe’s new pipe and the existing Telstra capacity. I have to say that I didn’t keep a copy of the article and did think it seemed low at the time even for current speeds.

      However saying all this, say I am 100% out with my figures and assuming that they move to 40 Gbps technology. That would give a figure 800% higher than the 3.5Mbps per connection. That would give me 28Mbps, still way short of the 100Mbps capacity of the NBN.

  2. Actually your numbers are wrong.
    Guam cables:
    AJC (sydney – guam – japan)
    1000Gbps

    PPC1 (sydney – png – guam)
    1920Gbps

    Don’t forget the other cables out of Australia:
    JASAURUS (Port Headland – Indonesia)
    5Gbps

    SEA-ME-WE3 (Perth – Singapore .. and on)
    480Gbps

    Southern Cross (Sydney – NZ & Hawaii onto US)
    2400Gbps

    Endeavour Cable (Sydney – Hawii)
    1200Gbps

    APNG-2 (Sydney – PNG)
    1.1Gbps

    TASMAN 2 (Sydney – NZ)
    1.1Gbps

    So I count 7006Gbps of capacity on existing cable systems (incl PPC1) out of Australia without adding any new ones. That’s a lot more thn the 6Gbps you are using in your numbers.

    Regards
    The Cable Guy

    1. Oops I was just rerunning the calcs with your figures and noticed that they didn’t add up. I had incorrectly used 4 and 6 Gb/s in the first paragraph, then when you look at paragraph 3 I have said the total capacity coming into Australia will be 6Tb/s (or 6000Gb/s) which is not too far off your figure at all.

      The calcs then run like this:
      100Mb/s = 0.1Gb/s
      6000Gb/s divided by 0.1Gb/s = 60,000 connections at full 100Mb/s speed
      Number of households in Aus is 8.5M
      Assume 20% connected at any one peak time. That give 1.7M connections.
      6000Gb/s = 6,000,000Mb/s available bandwidth
      6,000,000Mb/s divided by 1.7M connections give 3.5Mb/s per connection.

      Obviously you have a lot more accurate data than me, and I really apologise for my incorrect units and putting you to all this trouble, but unless you can see an error in my logic it would seem that 4.12Mb/s is as much as we can expect.

      I would guess that 20% of households on the web at one time is probably a massive overestimate at the moment, but in the future I’m not so sure.

      I really appreciate all the work you have put into this, and please let me know if you can see anything in my logic that may be wrong. If you think it stacks up maybe we can jointly post it somewhere?

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