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Full-Duplexing?

Discussion in 'Networks' started by Baba O'Riley, Sep 11, 2006.

  1. Baba O'Riley

    Baba O'Riley Gigabyte Poster

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    Hi guys, just got asked by my boss something I've never come across before. How do you/can you tell if your NIC is running at full or half duplex in Windows? The card is set to auto-config in Device Manager but that's as far as we got.

    Cheers.
     
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  2. Mr.Cheeks

    Mr.Cheeks 1st ever Gold Member! Gold Member

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    Device manager -> Nework adapters -> select NIC card -> Advanced and then its under Link Speed + Duplex
     
  3. Baba O'Riley

    Baba O'Riley Gigabyte Poster

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    Nice try but no cigar.

    The only relevant option I have is Media Type which is set to Auto_config (other options are half-duplex, full-duplex etc). However, this doesn't tell me what it's auto configged to.
     
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  4. Mr.Cheeks

    Mr.Cheeks 1st ever Gold Member! Gold Member

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    auto means its auto sensing (i think), if your card cant handle full speed that you lower the thing to half duplex...

    Cheeks (awaiting for correction)
     
  5. Baba O'Riley

    Baba O'Riley Gigabyte Poster

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    I think, as one of the configuration options is full-duplexing, it's safe to assume the card supports it.
    Auto config = auto sensing, correct. I want to know what it is auto-sensing to, IE. is the card automatically configuring itself to half or full-duplexing? I realise this can be worked out from what concentrating device it's connected to, but hypothetically, let's say I've no way of knowing what the PC is connected to. Is there a way to tell in Windows (with or without third-party software)?
     
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  6. simongrahamuk
    Honorary Member

    simongrahamuk Hmmmmmmm?

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    Some network cards have different coloured LED for different speeds of activity.

    See your NIC manufacturer for more details.
     
  7. Baba O'Riley

    Baba O'Riley Gigabyte Poster

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    I've not heard that before, it may be an avenue worth exploring. Thanks Si.
     
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  8. hbroomhall

    hbroomhall Petabyte Poster Gold Member

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    There are quite a number of cards that claim auto-full/half duplexing, but some don't deliver.

    A few good switches have LEDs that show if it has been negociated - I keep a slightly old Netgear around because it does this.

    In quite a few cases where NICs and switches don't cooperate correctly you need to nail the duplex in place.

    Harry.
     
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  9. Baba O'Riley

    Baba O'Riley Gigabyte Poster

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  10. r.h.lee

    r.h.lee Gigabyte Poster

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    Baba O'Riley,

    Which operating system?
     
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  11. Baba O'Riley

    Baba O'Riley Gigabyte Poster

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    Hi RH, the OS is XP Pro, and to anticipate your next question, I'm not sure what make the NIC is, but it shows in Device Manager as SiS 900 PCI Fast Ethernet Adapter. I believe SiS only manufacture the chipset.
     
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  12. Bluerinse
    Honorary Member

    Bluerinse Exabyte Poster

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    How to change your nic to half-duplex or full-duplex

    How to change your nic to half-duplex:

    Windows 2000 or XP:
    Open Control Panel.
    Double-click Network and Dial-up Connections.
    Identify the icon for your cable modem connection: usually Local Area Connection.
    Right-click that icon and select Properties.
    Under the ethernet adapter icon, click the button Configure.
    Click the tab Advanced to bring it to the front:
    In the Property box, the property name to be selected varies according to model of ethernet card. Examples are: Network Link Selection, Media Type, Connection Type, Duplex Mode, or any similarly-named property which can have Values looking like Auto-Negotiation, or 10BT, or 10BaseT.
    In the Value box, select a value which either (a) explicitly says half-duplex or semi-duplex, or (b) at least does not say full-duplex [e.g. 10BaseT on its own is OK]. If there is a choice between 10 and 100 with half-duplex, choose the 10. Do not choose 10Base5, 10Base2, or AUI.
    Click OK to exit the Adapter settings.
    Click OK to exit the Connection properties.if u are using a router at set network card 100 full

    The source
     
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  13. r.h.lee

    r.h.lee Gigabyte Poster

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    Baba O'Riley,

    Thank you for the additional information. However, my next question is different.

    How to figure out if your NIC is operating on full-duplex in Windows XP Professional:
    1. Click Start->Connect to> and select "Show all connections"
    2. Double click the icon representing your NIC.
    3. In the dialog box, under the "Activity" section, there should be a picture of two computers. Look carefully at the "monitors" on the two computers.

    The computer on the left represents your computer. When the "monitor" of that computer flashes, it means your computer sent a transmission. The computer on the right represents the remote computer. When the "monitor" for the right computer flashes, it means your computer received a transmission. As we know, a full-duplex communication is when a NIC is both sending and receiving a signal. Therefore, what you need to do is look carefully at both of those "monitors" and if both flash at the same time, voila you have proof that the NIC is operating at full-duplex.

    Now, let's also review networking. Assuming the Windows XP Professional computer's NIC is configured for "auto-sensing", then the next question is, what networking device is on the other end of the network cable from the NIC? If it's a hub, then the NIC is operating at half-duplex since hubs can't do full-duplex. If it's a switch, then the NIC may be running at half-duplex or full-duplex. If the switch port itself has a "full-duplex" light and that light is on, then the NIC is running at full-duplex. If the switch port itself has a full-duplex light and that light is off, then the NIC is running at half-duplex.

    I hope this helps.
     
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  14. Baba O'Riley

    Baba O'Riley Gigabyte Poster

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    OK, one at a time.

    Pete, as per my earlier posts, the NIC is currently set to auto-detect the conncection. We are going to run some speed tests on it this week with it set to both auto-detect and then manually set to full-duplex. Hopefully a comparison of the numbers might give us a clue as to whether the NIC is correctly configuring itself to full-duplex.

    RH, thanks for the viewing the monitors tip, I'll have a go at that. As for the concentrator the NIC is plugged into, it's a switch so the NIC should be switching to full-duplex. What I was after however, was a way of telling from the PC, for example if you don't have access to the switch.

    To be honest, this has stemmed from a PC at work that is seeming to run a bit slow on the network and my boss has got it in his head that it's not running at full-duplex. Personally, I think that part of things is fine but the politic thing to do is investigate his suggestion first I feel.
     
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  15. Bluerinse
    Honorary Member

    Bluerinse Exabyte Poster

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    So why not manually set it to full duplex? :blink
     
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  16. wizard

    wizard Petabyte Poster

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    Don't you just hate office politics :D
     
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  17. Baba O'Riley

    Baba O'Riley Gigabyte Poster

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    Pete, see above: "We are going to run some speed tests on it this week with it set to both auto-detect and then manually set to full-duplex."

    Yep, I don't very often do office politics myself. I tend to just say what I think, but it's a habit I'm trying to get out of.:D
     
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