fa0/0, s0/0/0

Discussion in 'Cisco' started by Ender, Aug 25, 2007.

  1. Ender

    Ender Guest

    Hi,

    I'm reading up on subnetting in a cisco 'networking basics' book and I
    keep running across diagrams that show the IP address of a machine w/
    something like FA0/0, S0/0/0 and I can't find what these mean or where
    they're explained in the book. I did find them in a table w/ a column
    header of 'output interface' but ... that really doesn't help me read
    the format.

    Any help much appreciated.
    Ender, Aug 25, 2007
    #1
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  2. Ender <> writes:
    >I'm reading up on subnetting in a cisco 'networking basics' book and I
    >keep running across diagrams that show the IP address of a machine w/
    >something like FA0/0, S0/0/0 and I can't find what these mean or where
    >they're explained in the book. I did find them in a table w/ a column
    >header of 'output interface' but ... that really doesn't help me read
    >the format.


    They are abreviated interface names. FastEthernet 0/0, Serial 0/0/0.

    When you have lots of routers/firewalls with lots of interfaces, it
    pays to keep track of the important details, like interface names and
    IP addresses and the like.
    Doug McIntyre, Aug 25, 2007
    #2
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  3. Ender

    Ender Guest

    On 2007-08-24 22:53:17 -0500, Doug McIntyre <> said:

    > Ender <> writes:
    >> I'm reading up on subnetting in a cisco 'networking basics' book and I
    >> keep running across diagrams that show the IP address of a machine w/
    >> something like FA0/0, S0/0/0 and I can't find what these mean or where
    >> they're explained in the book. I did find them in a table w/ a column
    >> header of 'output interface' but ... that really doesn't help me read
    >> the format.

    >
    > They are abreviated interface names. FastEthernet 0/0, Serial 0/0/0.
    >
    > When you have lots of routers/firewalls with lots of interfaces, it
    > pays to keep track of the important details, like interface names and
    > IP addresses and the like.


    Well, that kinda helps, F is ethernet, and S is serial, but why the
    numbers, and the slashes. I can see F0, or F1, or F2, but why the 0/0
    or 0/0/0?

    Are there other letters for other media? Or some sort of table on this
    anywheres?
    Ender, Aug 25, 2007
    #3
  4. Ender <> writes:
    >On 2007-08-24 22:53:17 -0500, Doug McIntyre <> said:


    >> Ender <> writes:
    >>> I'm reading up on subnetting in a cisco 'networking basics' book and I
    >>> keep running across diagrams that show the IP address of a machine w/
    >>> something like FA0/0, S0/0/0 and I can't find what these mean or where
    >>> they're explained in the book. I did find them in a table w/ a column
    >>> header of 'output interface' but ... that really doesn't help me read
    >>> the format.

    >>
    >> They are abreviated interface names. FastEthernet 0/0, Serial 0/0/0.
    >>
    >> When you have lots of routers/firewalls with lots of interfaces, it
    >> pays to keep track of the important details, like interface names and
    >> IP addresses and the like.


    >Well, that kinda helps, F is ethernet, and S is serial, but why the
    >numbers, and the slashes. I can see F0, or F1, or F2, but why the 0/0
    >or 0/0/0?


    Depends on the platform in use, and how they number interfaces on that
    platform. The simplest, smallest platforms like an old ancient 2501 or
    an 8xx series just have single #s. S0, S1, E0, A0. Bigger platforms
    that take modular cards tend to seperate out with slashs. So 0/0 is
    the card in slot0, the 1st interface on that card. Or, 0/0/0 could be
    the card in slot0, the WIC in spot 0 on the card in slot0, and the first
    interface on that WIC. If you get up to the BFR or 10k, you get one
    more layer deep, combine that with a channelized controller and a
    subinterface, and you can have things like 0/5/1/6:0.16.

    You'll get a feel for it while just using a cisco router. Nothing
    magical about it. Ie. if you have a computer with a few hundred hard
    drives attached you'd get lost pretty quickly trying to figure out
    which particular hard drive is number 84. Lot easier to figure out
    which controller, shelf, and drive number in the shelf. Same sort of thing.

    >Are there other letters for other media? Or some sort of table on this
    >anywheres?


    Its not really that important, they are just short abbreviations.
    Ethernet
    FastEthernet
    GigabitEthernet
    Serial
    HSSI
    ATM
    Loopback

    Can't think of any other types of interfaces that regularly get
    abbreviated, although there's quite a few more.
    Doug McIntyre, Aug 25, 2007
    #4
  5. Ender

    nasx12

    Joined:
    Jan 3, 2013
    Messages:
    1
    to Serial port not. the digits 0/0/0 means the number of "module/submodule/port" number, when you are logged on a real equipment there could be a different numbering depending of type of router. That is you have first module, first submodule, first Serial or Fast ethernet port of router.
    nasx12, Jan 3, 2013
    #5
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