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how do i do this? 100mb full duplex through switch

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  • 07-06-2015 12:45am
    #1
    dunworth1
    Registered Users Posts: 5,293 ✭✭✭


    i have upgraded to a 100mb leased line broadband and to achieve the full 100mb
    i have to set my laptop to 100mb full duplex when connected directly to the router otherwise i only get 10mb

    there is only one port on the isps router but i need to split the line into two routers one for admin network and one for public.

    but when i attach a switch to the isp router i only get 10mb down(i get the same when connected directly and not using 100mb full duplex) i have tried both a 100mb and 1gb switch both dumb switches

    anyone any ideas on how i can do this

    thanks


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    #2
    mass_debater
    Closed Accounts Posts: 3,072 ✭✭✭mass_debater


    dunworth1 wrote: »
    i have upgraded to a 100mb leased line broadband and to achieve the full 100mb
    i have to set my laptop to 100mb full duplex when connected directly to the router otherwise i only get 10mb

    there is only one port on the isps router but i need to split the line into two routers one for admin network and one for public.

    but when i attach a switch to the isp router i only get 10mb down(i get the same when connected directly and not using 100mb full duplex) i have tried both a 100mb and 1gb switch both dumb switches

    anyone any ideas on how i can do this

    thanks

    You could get something cheap that you can configure the port like a Mikrotik RB750 or RB750GL
    http://www.interprojekt.com.pl/rb750-p-560.html
    http://www.interprojekt.com.pl/rb750gl-p-1130.html


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    #3
    Cuddlesworth
    Registered Users Posts: 13,981 ✭✭✭✭Cuddlesworth


    dunworth1 wrote: »
    i have upgraded to a 100mb leased line broadband and to achieve the full 100mb
    i have to set my laptop to 100mb full duplex when connected directly to the router otherwise i only get 10mb

    there is only one port on the isps router but i need to split the line into two routers one for admin network and one for public.

    but when i attach a switch to the isp router i only get 10mb down(i get the same when connected directly and not using 100mb full duplex) i have tried both a 100mb and 1gb switch both dumb switches

    anyone any ideas on how i can do this

    thanks

    When you connect the switch to the router and the laptop to the switch, you get a 10Mbps connection on the laptop? Or you get a 1 gig connection with a only 10Mbps of speed. If it's the latter, I would start with the ISP that provided you with faulty equipment. If its the former, you have a problem with your laptop, not the router.


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    #4
    ED E
    Registered Users Posts: 36,166 ✭✭✭✭ED E


    You sure you arent just using the wrong cable? Presumably the ISPs router should have GigE out if the WAN is 100Mb, theres no way you should be falling back to a 10Mb link.


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    #5
    dunworth1
    Registered Users Posts: 5,293 ✭✭✭dunworth1


    I'm not sure if this isp router is gigabit or not I have no access to the control panel.

    If I let my laptop auto negotiate I get 100mb link but when I run a speed test I only get 10mb download and 60mb upload

    If I then set my laptop to 100mb full duplex I get 90mb down and 80mb up

    If I connect my laptop to the switch it doesn't matter if I set it to auto or full I only get 10mb down and 60mb up.

    Isp is saying that since I am getting the speed it's not their problem.

    Edit: same thing happens with another pc


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    #6
    Zynks
    Registered Users Posts: 1,693 ✭✭✭Zynks


    If the broadband service can give you 90/80 mbps speeds and your laptop can handle it (as has happened in the 2nd scenario above). The suspects should then be the cables and the switch. I would focus on those, starting by testing with different cables. Leave the network card set to auto while doing it.

    Another thing: do you have any type of VPN connection set?


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    #7
    dunworth1
    Registered Users Posts: 5,293 ✭✭✭dunworth1


    just to update this.

    i got hold of a managed switch and set the port speed manually to 100mb full duplex and we are now getting the correct speeds

    cheers for the help


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    #8
    Tenshot
    Registered Users Posts: 648 ✭✭✭Tenshot


    I ran into exactly this problem a few months ago on a customer site. When one side (ISP router) is configured to 100 Mbps full-duplex and the other side (your laptop or switch) is set to auto-negotiate, then the auto-negotiation defaults to 100 Mbps half-duplex since the full-duplex side isn't negotiating at all.

    The full-duplex side is happy to transmit and receive at the same time. When the half-duplex side sees incoming data at the same time as it is transmitting, it treats it as interference and throws it away. The sender doesn't know this has happened, so it's left to TCP/IP to notice & resend the data which slows everything right down.

    You won't notice for light web browsing but as speed increases (and especially with performance tests), more and more data gets discarded, leading to the poor results you saw. In my case, the customer had a 20 Mbps leased line from the provider, and only noticed the problem when they upgraded to 50 Mbps.

    Why do ISPs force the port to 100 Mbps full-duplex instead of leaving it on auto-negotiate? Mostly because of perceived unreliability issues with Ethernet auto-negotiation. With modern equipment (<10 years old), it should be a non issue. More info here and the original Sun paper it references (via Archive.org) here.

    That said: I actually came across an old 100 Mbps switch connecting two buildings just three weeks ago that had managed to auto-negotiate the trunk link down to 10 Mbps at some point during the past 15 months. Rebooting it restored the speed to 100 Mbps. The switch was a Nortel/Bay Networks Baystack 350-24T which dates back to 1998 or so; impressive it was still running at all!


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    #9
    gouche
    Registered Users Posts: 416 ✭✭gouche


    Tenshot wrote: »
    ...
    Why do ISPs force the port to 100 Mbps full-duplex instead of leaving it on auto-negotiate? Mostly because of perceived unreliability issues with Ethernet auto-negotiation.
    ...

    A lot of these issues come down to faulty cable / terminations.
    Removing Auto-Neg and forcing 100Mbps/Full works but Auto-Neg doesn't.
    So instead of finding root cause, engineer / ISP uses whatever works.

    See it myself in work. "Just set it 100Mbps/Full and we'll fix it later".


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    #10
    dunworth1
    Registered Users Posts: 5,293 ✭✭✭dunworth1


    gouche wrote: »
    A lot of these issues come down to faulty cable / terminations.
    Removing Auto-Neg and forcing 100Mbps/Full works but Auto-Neg doesn't.
    So instead of finding root cause, engineer / ISP uses whatever works.

    See it myself in work. "Just set it 100Mbps/Full and we'll fix it later".

    my issue wasn't due to a faulty cable anyway as i tried a cable i carry around with me to test directly from the router.


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