low committed information rate (CIR) of 24kbit/s per user

Discussion in 'NZ Computing' started by Andrew, Feb 13, 2006.

  1. Andrew

    Andrew Guest

    Andrew, Feb 13, 2006
    #1
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  2. Andrew

    Andrew Guest

    Andrew wrote:
    > From the computerworld article:
    > http://computerworld.co.nz/news.nsf/news/28363DAAB75B1F61CC2571140028E35A
    >
    > What exactly is CIR?
    >
    > 24 kbit/s... of what?
    >

    Okay.. i probably shoudlnt have bothered asking this as google told me
    straight away

    However, Just to clarify,

    Bear with me as i dont know the exact way to write these numbers, But
    just by reading it im sure you will understand.

    I have a 2mbit connection to the internet (128k upwards)
    I can effectivly download at 250kb per second

    With this CIR... xtra only guarantee 24kb per second speeds. IE if
    everyone in my neighbourhood connected to the same "thing" (dslam?) is
    downloading then my speed (and everyone elses) will reduce to 24kb per
    second (256k) - but not any lower

    However if no one in the neighbourhood was downloading then i could use
    right up to my top speed?
    Andrew, Feb 13, 2006
    #2
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  3. Andrew

    Richard Guest

    Andrew wrote:
    > From the computerworld article:
    > http://computerworld.co.nz/news.nsf/news/28363DAAB75B1F61CC2571140028E35A
    >
    > What exactly is CIR?
    >
    > 24 kbit/s... of what?


    And there lies the problem with UBS....

    For every 10 users on 256k, one can be using it at capacity, if 2 try, they will
    get half the speeds they should etc etc.

    Over a large number of users telecom assume that it will all sort itself out
    based on there useage figures from xtra users, who by definition dont know jack
    about the internet.
    Richard, Feb 13, 2006
    #3
  4. Andrew

    jedmeister Guest

    "Andrew" <> wrote in message
    news:s38If.146219$...
    > From the computerworld article:
    > http://computerworld.co.nz/news.nsf/news/28363DAAB75B1F61CC2571140028E35A
    >
    > What exactly is CIR?
    >
    > 24 kbit/s... of what?
    >


    I believe this is the guaranteed connection speed.

    The new plans quote the speed as being "...up to 3.5Mbps...".

    But, they actually mean....

    "...between 24Kbps and 3.5Mbps..."

    So, when there are lots of users connected, Telecom can drop the speed to
    24kbps and still be within their legal right.

    Doesn't look so flash now.
    jedmeister, Feb 13, 2006
    #4
  5. Andrew

    Tony Guest

    Andrew wrote:
    > Andrew wrote:
    >> From the computerworld article:
    >> http://computerworld.co.nz/news.nsf/news/28363DAAB75B1F61CC2571140028E35A
    >>
    >> What exactly is CIR?
    >>
    >> 24 kbit/s... of what?
    >>

    > Okay.. i probably shoudlnt have bothered asking this as google told me
    > straight away
    >
    > However, Just to clarify,
    >
    > Bear with me as i dont know the exact way to write these numbers, But
    > just by reading it im sure you will understand.
    >
    > I have a 2mbit connection to the internet (128k upwards)
    > I can effectivly download at 250kb per second
    >
    > With this CIR... xtra only guarantee 24kb per second speeds. IE if
    > everyone in my neighbourhood connected to the same "thing" (dslam?) is
    > downloading then my speed (and everyone elses) will reduce to 24kb per
    > second (256k) - but not any lower
    >
    > However if no one in the neighbourhood was downloading then i could use
    > right up to my top speed?
    >


    No, you have your bits and Bytes confused. What it actually means in
    this case is that per 3.5Mb/s customer Telecom will provision only
    0.024Mb/s on it's ATM backbone to carry that customers traffic (at ABR,
    ie the lowest priority level). This means that for you to get your
    3.5Mb/s full rate all 144 other customers sharing that 3.5Mb/s must be
    accounting for no traffic whatsoever. Now, this 145:1 over subscription
    is only on the New Zealand portion of the link, NOT the International
    portion. If Telecom had not based the ADSL network on their old ATM
    backbone there would not be such an issue.

    How well do you think this service will run at 145:1 over subscription ?
    Also bear in mind, for UBS it is still Telecom who determines this ratio.
    Tony, Feb 14, 2006
    #5
  6. Andrew

    Mark C Guest

    Andrew <> wrote in
    news::

    > Andrew wrote:
    >> From the computerworld article:
    >> http://computerworld.co.nz/news.nsf/news/28363DAAB75B1F61CC25711
    >> 40028E35A
    >>
    >> What exactly is CIR?
    >>
    >> 24 kbit/s... of what?
    >>

    > Okay.. i probably shoudlnt have bothered asking this as google
    > told me straight away
    >
    > However, Just to clarify,
    >
    > Bear with me as i dont know the exact way to write these
    > numbers, But just by reading it im sure you will understand.
    >
    > I have a 2mbit connection to the internet (128k upwards)
    > I can effectivly download at 250kb per second
    >
    > With this CIR... xtra only guarantee 24kb per second speeds. IE
    > if everyone in my neighbourhood connected to the same "thing"
    > (dslam?) is downloading then my speed (and everyone elses) will
    > reduce to 24kb per second (256k) - but not any lower
    >
    > However if no one in the neighbourhood was downloading then i
    > could use right up to my top speed?


    I believe the 24 kbit/s comes from the limit that Telescum apply to
    the pipe between Telescum and the ISP.

    As Tony said, this is bits, not bytes. The CIR is only 3 kByte/s.

    Telescum limit the connection between you and your ISP in at least
    two places.
    One of those places is the final connection between Telescum and your
    ISP. That single connection contains all the the data for all
    customers of that ISP.
    Telescum limit that connection to a "nominal" 24 kbit/s per customer.

    I imagine that an ISP could get that "nominal" rate changed if they
    wanted to, and some of the ISPs may (I imagine) have had that rate
    changed. IF they changed it, their total user base might then use
    more traffic, and if the aggregate average traffic goes over 10GB per
    customer, Telecom charge the ISP ~$2.80 per GB over the ISP-wide
    allowance. I imagine that Orcon might be in this situation, and that
    they haven't therefore changed the nominal rate.

    The other place Telescum limit the traffic is between the
    neighbourhood DSLAM and the next point within the Telescum network.
    They limit this to a 50:1 contention ratio.
    If, across ALL ISPs using the DSLAM (including Xtra), there are 100
    2mbit/s users, and 100 256kbit/s users, that gives total bandwidth of
    225.6mbit/s, so they nominally provision 1/50 of that, or ~4.5mbit/s
    between that DSLAM and the next upstream point. Those 200 users all
    share the 4.5mbit/s link. The 2mbit/s users get a larger share of it
    than the 256kbit/s users.

    (Contention ratios of 50:1 make NO SENSE for the low bandwidth rates
    we have in NZ. If we had 24mbit/s, then 50:1 is probably fine.
    50:1 is total stupidity for 256kbit/s "broadband".)

    Here's what Telecom think of the 24kbit/s limit:
    | "With the current user base comprising a majority of 256kbps
    | connections this over provides for the amount of bandwidth |
    required."

    Yeah, Right.

    HTH,
    Mark

    References here:
    http://www.telecom.co.nz/content/0,3900,204215-202771,00.html
    http://www.telecom.co.nz/binarys/technical-info-ubs.pdf (page 5)

    http://www.telecom.co.nz/content/0,3900,203436-202766,00.html
    http://www.telecom.co.nz/binarys/ws_bulletin_august_24_2005.pdf
    Mark C, Feb 14, 2006
    #6
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