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  • #2233620

    DSL Speed Influenced by Modem?


    by rafal ·

    I’m curious if DSL bandwidth is dependant on the modem model.
    Everyone knows that a big part in DSL bandwidth is played by the technology used (SDSL, ADSL, VDSL,..) as well as the distance from the CO. My question is, does the quality of the equipment increase or decrease the connection speed?

    Maybe someone did or knows of a source of DSL Modem tests/benchmarks…

    I’m looking forward to your input.

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  • Author
    • #2610439

      Yes and No….

      by jamesrl ·

      In reply to DSL Speed Influenced by Modem?

      Many ISPs limit the max speed in the firmware of their modems, or do other things to limit the speed, so a faster modem may not help.

      In other cases, some more expensive modems are better at throughput.

      Big question to ask – are you getting anywhere near your stated service levels?


      • #2511878

        In my case

        by rafal ·

        In reply to Yes and No….

        In my case my DSL provider offers 3-6MBits down and 512-876KBits up. On my curent setup I only get 5.1Mbits down and 500KBits up.
        From what I know they run on ADSL standard but plan to switch to ADSL2 in the future (when? nobody knows)

        I’m getting a D-Link ADSL Router which can handle:
        ? Downstream: Up to 24Mbps
        ? Upstream: Up to 3.5Mbps


        So I will put the theory to the test.

        • #2511859


          by jamesrl ·

          In reply to In my case

          Unless your provider has done a “silent” network upgrade (which does happen) then you won’t gain a thing.

          Your speed is as fast as the slowest link in the chain. And the slowest link will be either how the DSLAM at the CO is configured, or the equipment at the ISP.

          ISPs do incrementally upgrade their services sometimes and a fatsre router can sometimes take advantage of it. But I doubt you will see a huge improvement.



        • #2511798


          by rafal ·

          In reply to Unless

          But worth a try, especially since I need a new router anyway. 🙂
          Plus this will prepare me for the future ADSL2 or ADSL2plus.
          24Mbits/s sounds very nice.

      • #2946210

        Speed is determined by…

        by c f usa ·

        In reply to Yes and No….

        Having worked for two ISP’s one cable based, the other telco I can tell you that with DSL the speed (at least the company I worked for) was determined by the login, not the equipment.

        If Customer at 101 Main St had the high speed 6Mbps, and the customer at 102 Main St, had low speed 1.5, they would share the same type of modem.

        With the login information being stored in the modem, you could take the modem from 101 Main Street and place it 102 and get the higher speed.

        It was all about the login.

        Hope this helps, if not I have risked the “trade secret” for naught. I must leave now as I think “they” are coming for me.

        • #2946206

          As the original poster asked….

          by jamesrl ·

          In reply to Speed is determined by…

          If quality of the equipment had any influence. And having worked at a manufacturer of telecom equipment, I can’t answer anything but yes.

          Try going onto a DSL forum. Lots of people there trade up their modems to get better ones.

          Yes your ISP sets a class of service. But with the cheapest modem, you won’t get close to it. Better modems mean you can get closer to the maximum your ISP will provide.

          Yes, for some people it won’t be a huge difference, but it is there. If you read the post where the OP put his test results you will see he got a roughly 7% improvement. Might mean something to someone who does a lot of downloading.


    • #2512787

      Test Results

      by rafal ·

      In reply to DSL Speed Influenced by Modem?

      The increase in speed is present but almost insignificant. The connection is indeed set to 6000Mbps downstream and 768Kbps upstream.
      After Switching to a newer faster modem I can get peak 5.4Mbps downstream and 570Kbps upstream. This means that the downstream bandwidth increased from 5.1Mbps and the upstream from 560Kbps.

      This is not a significant increase and considering that the connection is rated for more it does seem that the length of the wiring has the most influence on the actual speed of the connection.

      Hopefully the ISP adopts ADSL2 or ADSL2+ since the new equipment is already compatible. 24Mbps/3Mbps would be really nice,

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