Which cable do I use to connect PC to Cisco router?

Discussion in 'Cisco' started by Darth Tyrannus, May 20, 2005.

  1. I want to download the configuration using tftp server, but I can't
    seem to find the proper cable to use for connecting my laptop to the
    ethernet port on the router. Is it a crossover or straight through? I
    actually tried both kinds and still couldn't get the link light to turn
    green. Also, if anyone has a link to the proper cabling for all
    network devices that would be great.
     
    Darth Tyrannus, May 20, 2005
    #1
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  2. "Darth Tyrannus" <> writes:
    >I want to download the configuration using tftp server, but I can't
    >seem to find the proper cable to use for connecting my laptop to the
    >ethernet port on the router. Is it a crossover or straight through? I
    >actually tried both kinds and still couldn't get the link light to turn
    >green. Also, if anyone has a link to the proper cabling for all
    >network devices that would be great.


    Anytime that you hook up two end-devices like routers, PCs, print
    servers, etc. two together to one another, you'll need a crossover
    cable. A switch or hub already all have their ports crossed over, so
    hooking up an end-device to a switch uses a straight-thru cable. When
    hooking up two switch ports together, you need to straighten one out
    again, so you use a cross-over cable again.


    Of course, there's tons of exceptions now-a-days, most for the better.
    Many switches now-a-days auto MDI/MDI-X so you don't need to think
    about these rules. Many end-devices can also auto-determine what you need.

    Unfortunatly, some small SOHO CPE devices that are designed with the
    thought of only ever hooking up one PC to them expect a straight-thru
    cable and switch around the wires as they come in, so it crosses it
    over for you without your knowledge, and messes up the rules again,
    you need a cross-over cable to hook them up to a switch, which is
    opposit of what you would think.


    Make sure that you plug your cross-over cable from your PC's ethernet
    port into the Cisco router's Ethernet or FastEther port.. And then the
    console cable from your serial port into the "Console" port.
     
    Doug McIntyre, May 20, 2005
    #2
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  3. In article <>,
    "Darth Tyrannus" <> wrote:

    > I want to download the configuration using tftp server, but I can't
    > seem to find the proper cable to use for connecting my laptop to the
    > ethernet port on the router. Is it a crossover or straight through? I
    > actually tried both kinds and still couldn't get the link light to turn
    > green. Also, if anyone has a link to the proper cabling for all
    > network devices that would be great.


    The general rule is that you use straight-through cables when connecting
    to a switch, and cross-over when connecting two nodes directly.

    --
    Barry Margolin,
    Arlington, MA
    *** PLEASE post questions in newsgroups, not directly to me ***
     
    Barry Margolin, May 20, 2005
    #3
  4. Darth Tyrannus

    Guest

    Agree with above.

    By default Cisco router ports are shutdown.
    You may have to log on using the console port
    and fix that first.
     
    , May 20, 2005
    #4
  5. Darth Tyrannus

    Guest

    > Also, if anyone has a link to the proper cabling for all
    > network devices that would be great.


    Here's link to lot of Wiring Stuff that you might find useful

    http://www.zytrax.com/tech/layer_1/

    -Ripple

    Darth Tyrannus wrote:
    > I want to download the configuration using tftp server, but I can't
    > seem to find the proper cable to use for connecting my laptop to the
    > ethernet port on the router. Is it a crossover or straight through?

    I
    > actually tried both kinds and still couldn't get the link light to

    turn
    > green. Also, if anyone has a link to the proper cabling for all
    > network devices that would be great.
     
    , May 20, 2005
    #5
  6. Thank you for all your help. This leads to another question. When I
    plug in the crossover cable into the cisco router should the green link
    light become active? The reason I ask is because I used this
    particular crossover cable and went from ethernet to ethernet port on
    two routers and I got a green link light on the AUI. But when I used
    this same cable and plugged it into my PC and one of those routers, I
    didn't get a green link light.

    Isn't the link light completely physical layer? Meaning, I shouldn't
    have to configure any procotcols or layer 2 addresses in order to
    obtain a green LED light on each device. This is where I'm running
    into problems. I need to understand the reason the link light turns
    green. I'm guessing that a signal is sent from one device to the other
    and if it received properly then both lights will become green. But
    this would require some sort of layer 1 protocol, correct?
     
    Darth Tyrannus, May 20, 2005
    #6
  7. In article <>,
    Darth Tyrannus <> wrote:
    :This leads to another question. When I
    :plug in the crossover cable into the cisco router should the green link
    :light become active?

    Not if the interface is shutdown.

    :Isn't the link light completely physical layer? Meaning, I shouldn't
    :have to configure any procotcols or layer 2 addresses in order to
    :eek:btain a green LED light on each device.

    On router interfaces, the link layer is turned off until the
    router is told to turn it on. Amongst other things, this saves energy
    when the link is a laser GBIC...

    :This is where I'm running
    :into problems. I need to understand the reason the link light turns
    :green. I'm guessing that a signal is sent from one device to the other
    :and if it received properly then both lights will become green. But
    :this would require some sort of layer 1 protocol, correct?

    The "layer 1 protocol" involved could be as simple as "was able to
    detect a signal". But usually it's a little more complex than that:
    the link light does not, for example, usually light if the devices
    are not able to negotiate speed [but it -will- light if the two devices
    fail to negotiate duplex.]


    :The reason I ask is because I used this
    :particular crossover cable and went from ethernet to ethernet port on
    :two routers and I got a green link light on the AUI. But when I used
    :this same cable and plugged it into my PC and one of those routers, I
    :didn't get a green link light.

    Could mean that router doesn't want a crossover to talk to the PC.
    Could mean that the port speed couldn't be determined.
    --
    Entropy is the logarithm of probability -- Boltzmann
     
    Walter Roberson, May 20, 2005
    #7
  8. I finally got the crossover cable to work and both sides of the link
    are up and green. Now I am having a problem with ARP.

    The cisco router has created an incomplete entry in its arp table for
    the workstation. The workstation has no arp entry for the router. I
    created ip address that were on the same C subnet. I manually added a
    static ARP entry to the workstation but could not ping the router. I
    am running Windows ME.


    My next question is...how does Windows ME create ARP table? If this
    workstation queries the media, with the router being the only device on
    the media, shouldn't the router respond with it's MAC address? The
    only table that is partially complete is the routers ARP table, which
    has an incomplete entry for the workstation.



    I cannot ping and am trying to get ARP to work correctly.

    Need help! :)
     
    Darth Tyrannus, May 21, 2005
    #8
  9. In article <>,
    Darth Tyrannus <> wrote:
    :My next question is...how does Windows ME create ARP table?

    It sends out an ARP broadcast packet requesting information on
    the remote destination.

    : If this
    :workstation queries the media, with the router being the only device on
    :the media, shouldn't the router respond with it's MAC address?

    Only if the router has been configured with an IP address on the
    link and configured to turn on the interface.

    :The
    :eek:nly table that is partially complete is the routers ARP table, which
    :has an incomplete entry for the workstation.

    An incomplete entry in an ARP table indicates that the device has
    recently sent out an ARP query but has not received a response, and
    that the device has not yet given on on waiting for the response.

    An incomplete ARP entry is NOT proof that there is communications
    in either direction.


    On the router side, do a "show interface" to check that the
    interface is considered to be up. You can also "debug packet"
    to see what is being received. On the Windows ME side... I'm not
    sure. If you had a later version of Windows, you could download
    libpcap and ethereal and snoop to see -exactly- what was on the wire.
    I don't know if that is supported on ME.
    --
    "No one has the right to destroy another person's belief by
    demanding empirical evidence." -- Ann Landers
     
    Walter Roberson, May 21, 2005
    #9
  10. I did a show interface and everything seems to be ok on the router
    side. It has to be the Windows ME workstation. Maybe for some reason
    it's not responding with it's own IP address when ARPed.

    I'm guessing my next step is to check on the web for Windows ME ARP
    behavior. Lord knows where I will find this...

    The workstation works ok with ARP on my linksys router, but when I go
    to the cisco router it's a no go.
     
    Darth Tyrannus, May 22, 2005
    #10
  11. I finally figured out the problem. The ethernet interface on the
    router is not functioning properly. I finally decided to try the other
    ethernet interface and everything worked perfectly. I also tried
    another ethernet interface on a seperate router and again no problems.
    The interface that was giving me problems was acting sporadically.
    Ocassionaly the line protocol would come up, sometimes it would
    "transmits stalled: check cable connection:", and when I initially
    started working with it I was able to recieve some ARP info.

    Thanks for your help Walter!
     
    Darth Tyrannus, May 23, 2005
    #11
  12. Darth Tyrannus

    theapplebee

    Joined:
    Jun 19, 2009
    Messages:
    67
    Location:
    USA
    Router is considered as DTE.
    PC is DTE as well, so connecting DTE to DTE.
    USE cross-over cable for Ethernet port.
    Of course use Cisco console cable for console port.

    Sharing Cisco Expertise : www.ipBalance.com
     
    Last edited: Apr 17, 2010
    theapplebee, Oct 30, 2009
    #12
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