The Great Big NBN Sticky Thread

Discussion in 'Networking, Telephony & Internet' started by Akh-Horus, Dec 21, 2016.

  1. Oblong Cheese

    Oblong Cheese Member

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    I've had my service restored but I do not think it is on the micronode just yet. The guys who came to fix my line were also there to fix two other premises in my street, so I wasn't the only one!

    They had to take two runs from two different pairs to get me a working pair, so I suppose I can forgive the other guys installing the new copper if they mistakenly disconnected something they thought was an unused line... but still. I work in a closely related industry and there is no way in hell I would ever leave a work site without having verified that all the cabling I touched/modified was working as intended.

    I hope you got your problem resolved! Was caspian helpful in the end? :D
     
  2. fredhoon

    fredhoon Member

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    Is it this team?

     
  3. kaine88

    kaine88 Member

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    Well after some NBN maintenance last night my upload seems to be back to normal. Many thanks to the NBN gods for restoring my extra Mbps
     
  4. caspian

    caspian Member

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    you may be surprised the amount of stuff that gets fixed because I and other people get quality real time feedback from here and other sources. nothing that wouldn't happen anyway via normal channels, but that process does take a certain amount of time.
     
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  5. Stewey

    Stewey Member

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    I'm curious if anyone knows how the speed limiting works on NBN based plans?
    All speeds given are averages over 24 hours.
    I signed up with a plan for 50 down and 20 up. I could only only achieve 23 down and 19 up on FTTN so I asked the RSP what they could do.
    We agreed that going down to a 25 down 5 up plan would be the most sustainable option.

    Once I was downgraded I could now achieve 21 down and 3 up. This is where I get confused as I thought I would easily get the 5 up on this plan which would have made it usable for me.
    Does anyone know why it would get limited below the plan rate when I can achieve the maximum on my line?
     
  6. Doc-of-FC

    Doc-of-FC Member

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    you say line, so I'm assuming FTTN.

    The download and upload frequencies are binned into an upper frequency band on VDSL2, from my understanding this is to minimise X-talk with the existing ADSL network, see here:
    http://educypedia.karadimov.info/electronics/VDSL2.png

    As you can see in the graphic, the older ADSL upload has its own carved out range of frequencies, which is why most people had a relatively reliable 1mbit of upload and then a variable download rate due to the laws of physics.

    Due to your speed change, the overall allocated 'bins' gets reduced, the layer 1 throughput is reduced to deliver (including overhead) the 25/5 layer 2 rate, beyond this you lose 40 bytes per frame in ethernet and TCP/IP overhead, possibly some more due to PPP (8?) throw in some NBN packet loss and some service policy voodoo in your RSP's equipment on their side of the NNI (RED + WRR on the LER) and you've got yourself a perfect storm of first world problematic internet instability.

    Your test rate is based on a layer 3 delivery that probably isn't counting stuff with any serious degree of accuracy, throw in some more internet backbone voodoo and you've arrived at your answer.
     
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  7. kaine88

    kaine88 Member

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    Your downstream rate seems a bit low compared the upstream. With 19Mbps up I would have expected you to easily get 50Mbps down (at least when compared to other FTTN speeds reported over on Whirlpool).

    Did your ISP run any NBN tests/diagnostics on the line to see if there were any issues?

    Do you have more then 1 phone socket in the house? If so it might be worth getting someone in to tidy up/disconnect the other sockets.
     
    Last edited: Feb 22, 2019
  8. Stewey

    Stewey Member

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    Thanks Doc, that explains it pretty well for my 5 up speed reading.

    Yes NBN did run some tests and found that the maximum my phone line can get is 27 down.
    I also do have two phone sockets, the first one is in our bedroom and on the opposite side of the wall to the lead in joint so the cable is really short to it. The other is in the study and about 10mts of cable further away. Testing the modem plugged into the first socket in our bedroom yields very little gain, less than a Mbps over the one in the study.
     
  9. kaine88

    kaine88 Member

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    I'm pretty sure they can get the line rates without running any of the tests. When Aussie Broadband have run tests on my line it has taken around 5-10mins for each and one of them requires the modem to be disconnected. It might be worth just double checking if they did run those tests or not. They can help identify issues with the line that might be causing a degradation in speed e.g. bridge taps.

    It seems to be a general rule of thumb to only have one active socket on FTTN. Any additional sockets that are connected can potentially cause a drop in line rates.
     
  10. Doc-of-FC

    Doc-of-FC Member

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    Talk to your RSP, testing may reveal a bridge tap.

    I'd also look to ensure you're using a Broadcom chipset for your DSL modem as it does have an impact on train up, again your RSP may be able to help in this area. Alternatively OCAU buy and sell (for a small fee) may get you something.
     
  11. arytel

    arytel Member

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    Thanks for your reply. I thought I might have to discuss this with the techs on the day, and maybe make myself available to assist if necessary.
     
  12. caspian

    caspian Member

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    they can get them via a number of methods, although some are real-time and others are quite slow and meant more for reporting style applications, not testing. the best is a port state snapshot which is similar to Telstra's old RVOP test, it gives real-time view of bitrates, target noise margin, attenuation etc. it takes about 1-2 mins to run and isn't disruptive, the modem must be in sync for it to return anything of use.

    the one requiring disconnection is a SELT test, which is a simplified TDR test. it works on reflectometry, so you need a known state for the test to run (line only), because the capacitance and impedance change of anything connected (like a modem, even if powered off) distorts the results beyond practical usability. with the line open (i.e. unterminated) at the far end, a combination of SELT and DELT testing can be quite good at detecting the presence of bridge taps, which aren't a fault in of themselves, but can certainly cause performance to drop well below what would otherwise be possible.

    yes. VDSL2 is far more susceptible to common ends (a.k.a. bridge taps, star wiring etc) than previous forms of DSL modulation, because the pre to post tap line lengths typically place the frequency of an in-premises tap into the spectral range that VDSL2 uses. the issue has always been there, it just wasn't troublesome prior to now. think of it like a small bump in the road, at 60km/h in a Camry it has little effect. now hit it at 300km/h in an F1 with suspension engineered to expect a very smooth surface. same issue, much greater perceived effect.
     
    Last edited: Feb 25, 2019
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  13. caspian

    caspian Member

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    rate limiting is applied in a couple of places, to achieve different things. the one you can see is that your ordered speed tier causes a speed profile to be applied to the DSLAM port, which sets the maximum actual bitrates that can be achieved. there is further logical limiting applied further inside the network.

    there is nothing configurable that could cause those symptoms. the only possibilities are that either something has changed WRT the transmission capabilities of your line, or your line was under DLM control and it reacted to a change in circumstances.
     
  14. CptVipeR

    CptVipeR Member

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  15. CQGLHyperion

    CQGLHyperion Member

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    Reading that once again made me angry and sad.
     
  16. neopheX

    neopheX Member

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    Hey guys just a quick question,

    My brothers and sister in law's property has NBN available now (HFC) they're keen on AussieBroadband but I am wondering what HFC modem is provided Is it the ARRIS CM8200 that is provided across everyone on NBN HFC?
     
  17. caspian

    caspian Member

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    yes, because NBN provides the modem. your ISP should provide a router.
     
  18. neopheX

    neopheX Member

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    Great thought as much. I got signed up to NBN HFC over 2 years ago and got the AARIS CM8200 but couldn't remember if NBN does this or the RSP.

    Cheers
     
  19. Primüs

    Primüs Member

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    Keep in mind, the modem will not act as your router - it is similar to the Fiber to the Home NTD's, its just there to media-convert, a router behind it will still make the connection to your RSP, whether that be a BYO router or supplied by your RSP.
     
  20. jcorney

    jcorney Member

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    Ok. Parents FTTN in tassie. Sync at 8/5. Original node they were connected to is almost 1500m away.

    New node installed to the street between their house and the original node. Speed is obviously still arse so assuming the connection hasn’t been moved.

    My questions are.
    How long does it normally take to commission a node once it’s installed?
    Does the isp need to request a transfer to the new node?
    Is it possible as a customer to see which node your service is connected to?
     

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