ARP protocol's purpose - TCP-IP

This is a discussion on ARP protocol's purpose - TCP-IP ; Hi, I saw some ARP messages come out of Tropos APs ".......who has x.x.x.x tell.........." As far as I know ARP is used to find out MAC address to a known IP address. In this case Tropos is clearly aware ...

+ Reply to Thread
Results 1 to 3 of 3

Thread: ARP protocol's purpose

  1. ARP protocol's purpose

    Hi,

    I saw some ARP messages come out of Tropos APs ".......who has x.x.x.x
    tell.........." As far as I know ARP is used to find out MAC address
    to a known IP address. In this case Tropos is clearly aware of the
    client's IP address then why is it sending these messages?
    Can ARP also be used as keep-alive?

    TIA


  2. Re: ARP protocol's purpose

    On Mon, 13 Aug 2007 13:02:07 -0700, Kalyan wrote:

    > Hi,
    >
    > I saw some ARP messages come out of Tropos APs ".......who has x.x.x.x
    > tell.........." As far as I know ARP is used to find out MAC address to
    > a known IP address. In this case Tropos is clearly aware of the client's
    > IP address then why is it sending these messages? Can ARP also be used
    > as keep-alive?


    Arp entries have a timeout. This varies greatly between devices, ranging
    between 1 minute and 4 hours. After the timeout the device re-queries for
    the mac address of the device.

    HTH,
    M4

  3. Re: ARP protocol's purpose

    On Aug 13, 1:02 pm, Kalyan wrote:

    > I saw some ARP messages come out of Tropos APs ".......who has x.x.x.x
    > tell.........." As far as I know ARP is used to find out MAC address
    > to a known IP address.


    Correct.

    > In this case Tropos is clearly aware of the
    > client's IP address then why is it sending these messages?


    To get the MAC address. As you stated, ARP is used to find out the MAC
    address to a known IP address.

    > Can ARP also be used as keep-alive?


    I don't understand what you are asking. I suppose it is possible for a
    device to use an ARP query as a way to confirm that a device is still
    present, if that's what you mean.

    DS


+ Reply to Thread