Strange Phenomenon after Having nbn FTTP Installed, Any Ideas?

Hi everyone, wondering if someone can help with this weird issue I'm having with my FTTP connection. Just had it installed today.

For reference the FTTP box was installed in Room 1. The Gigabit Bridge is installed in room 2, as that is where all the Cat 5E cables run from to get to other rooms. I have drawn a diagram to show what's happening.

When I plug in my Telstra Smart Modem near the FTTP box in room 1, and connect it with a Cat 6 cable to the WAN port, and then to the gigabit bridge by the existing wiring to room 2, the devices all plugged into the bridge are showing up in the Telstra modem's admin page as only connecting at 100mbps.

When I plug the modem near the bridge in room 2, plug the house's Cat 5E cable into the FTTP box, and then to the modem, and a Cat 6 cable from the modem to the bridge, all the devices are showing up in the modem's admin panel as connecting at 1000mbps.

It's doing my head in, because all the cabling is the same between the two scenarios, but for some reason only the long Cat 5E cable allows all the devices plugged into the bridge to connect at 1000mbps.

Does anyone have any ideas?

Diagram here, hopefully it makes sense.

Edit: FTTP is 1000/50 plan

Comments

  • +4

    Bad cable/bad contact/broken pair.
    You’ll know for sure if you have another set of cables to test.

    In scenario 2, I suspect you may only be getting 100Mbps between FTTP box and modem.

    You need to do an elimination test.
    You have too many things going on. Break it down.
    Start by plugging your PC directly to FTTP box using Cat5e and check the speed. Do the same for Cat6.

    • Possibly, but it's all the same cables for both scenarios, just set up differently.

      I did a speedtest.net test on both scenarios - in scenario 1 I get around 80mbps, but in scenario 2, it's about 600mbps.

      I'll see if I can test a shorter cable length as you said and see what happens.

      • -1

        Possibly, but it's all the same cables for both scenarios, just set up differently.

        RF interference ?

        • I wouldn't have thought so - but wouldn't RF interference affect both scenarios the same?

          The Cat 5E cables are run through the walls of the house, so it's not so easy to replace them with Cat 6 - but even with Cat 5E, in scenario 2 I'm still getting massively fast speeds.

          • -1

            @Flying Ace:

            but wouldn't RF interference affect both scenarios the same?

            Depends where other cables are running and their orientation to the ethernet cable.

      • What type of router are all the devices in room two the main connection room connected to? Is it a router or a switch.?
        Is the device capable of 1000Mbps a lot of consumer grade routers are only able to handle 100Mbps connections.
        You need to make sure all routers and switches can do 1000Mbps or lower your NBN speed.

  • +4

    Looks like long cable is the issue here

    • +3

      Yeah, spot on.
      The modem is measuring the Local Area Network (LAN) speed, not the Wide Area Network (WAN) speed.
      Replace the cat 5E cable with a cat 6 cable (or better).
      To test, disconnect the cable between the NBN NTD and the Telstra modem (this connection is not required for testing the local network). Then test the 2 different cables between the Telstra modem and the gigabit bridge. You will get the same results.
      You can also directly connect a device to the Telstra modem (remove the bridge), and test all network cables to determine speeds.

  • planning to stay with Telstra for 24 more months? ask for gen3 modem its free if you stay for 2 years

    • Not with Telstra - I'm with Superloop but using the Telstra modem. Not related to my issue though.

      • I'm with Superloop

        Let us know how your speeds and latency go…

        I'm considering switching…

      • Which Telstra modem are you using with Superloop ?

        • Telstra Smart Modem Gen 2 - as I wrote in the OP :)

    • +3

      People are so impatient these days. You didn’t need to make a post for this, just wait until 8:30am and let the experts give you the correct answer - that is your only option.

  • Agree with above, the issue looks to be your long cable.
    A cable tester could help you diagnose it, if you're handy you could check and reterminate the wall plates, or if you only have 100mb NBN you could not worry about it :)

    • But why would the long cable only be an issue when it's plugged directly into the modem, and from the modem to the bridge?

      When it's plugged directly into the bridge, and then the short cable from the bridge to the modem, I get excellent speeds.

      This is what I don't understand. The long cable is in use regardless of which configuration I use, but only in one configuration does it result in slow speeds.

      • +1

        because you're link speed to the modem is being impacted in the first scenario
        no idea what your 'gigabit bridge' is, but devices are only going to synch at their connection speed to their end point device.
        Try a single device connected to the wall point at the end of your long cable. Should be relatively simple to plot out link paths and show the one which isnt performing as expected.

        in scenario 2 everyone is getting 1gb to the router, then the router to the internet is only 100mb
        in scenario 1, everyone is only getting the shared 100mb to the router

        Get a long cat cable and run it along the floor to replicate the hard wired cabling through your wall to prove it.

  • +2

    It's a dodgy cable, likely just one of the wires has popped off the keystone at one end. (need 3 pairs (6 wires) connected for 100mbps, need 4 pairs (8 wires) connected for gigabit)

    Your local network speed is measuring the speed of connection between your computer and the modem/router only. Anything the other side of the modem/router is limited by your NBN plan speed.

    I've outlined the difference below with the brackets identifying the part of your network that you're measuring.

    Scenario 1
    NBN NTD - (Modem/Router - 100mbps only dodgy cable - Network Switch - Measuring device)

    Scenario 2
    NBN NTD - 100mbps only dodgy cable - (Modem/Router - Network Switch - Measuring device)

    Do a speedtest.net speedtest to test your internet speed in both scenarios. If you're on a 100mbps NBN plan, then leave the setup in scenario 2 configuration. If you're paying for faster NBN ie 250 or higher, then you may want to downgrade or get the cable connection fixed.

  • @Flying Ace Call Superloop support if your NTD optical port is still off. nbn may have to come fix it. I'm assuming you have switched the NTD and router off and on again?

    • +1

      Yeah, several times. Superloop have raised it with NBN. Hopefully won’t take too long to resolve.

    • Won't be out until Monday - it was a glorious 3 hours of 600+mbps speeds, now back to standard 100mbps :-(

  • +1

    Can you try plugging a computer directly into the NBN FTTP box with each cable and doing a speed test? If one of these speed tests shows 100mbps then it is a dodgy cable.

    It could be that a wire in the cable was not terminated correctly and is only intermittently connected. To test this theory, bend the cable slightly, close to the connector, in multiple directions, while running speed test. Repeat this for each end of the cable and for both cables. If the speed drops or the internet disconnects when you bend it, then the cable is faulty.

    It could also be because a port on the telstra modem or switch is faulty and the signal integrity is not good enough, causing it to not be able to communicate at 1000mbps with the long cable and fall back to 100mbps. Once you have confirmed both cables are good, try doing a speed test using the long cat 5e cable connected directly to each LAN port of telstra modem, if the speed test shows 100mbps then it means that port on the telstra modem is bad. Then try doing a speed test connected directly to each port of the switch using the long cat 5e cable, if the speed test shows 100mbps then it means that port on the switch is bad. (You need to find an alternative way of getting internet to the switch, or use something like iperf3 to do the speed test over LAN)

  • +2

    I've seen lots of issues like this usually with the cable's ends being finicky, as others have said.

    In one particular instance, a solar installer who ran cat5 from the inverter to the monitoring box at the router, and couldn't figure out the connectivity issues. It wasn't until I checked and pointed out he wasn't following the 568B standard… he was simply putting the four colour pairs in order across each of the terminals!! "It usually works fine…" which would have been the case on a very short run at 100mbps, but in this case it was 30+m and the mismatched pairs were too far off spec to connect successfully to the router.

    • +1

      Wow. Just shows there's a difference between not being a licenced cabler and flat out having no idea!

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