ospf mask

Discussion in 'Cisco' started by zibin, Oct 30, 2006.

  1. zibin

    zibin Guest

    why is ospf netmask needs to be in the form of 0.0.255.255, but not
    255.255.0.0? Was it just simple preference, or it has deeper reasons?
     
    zibin, Oct 30, 2006
    #1
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  2. In article <>,
    zibin <> wrote:
    >why is ospf netmask needs to be in the form of 0.0.255.255, but not
    >255.255.0.0? Was it just simple preference, or it has deeper reasons?


    Internally ospf uses 255.255.0.0 format.

    Are you perchance referring to the "router ospf" "network" statement?
    If so, then it is cisco's standard notation on "network" statements,
    not specific to protocol.
     
    Walter Roberson, Oct 30, 2006
    #2
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  3. zibin

    zibin Guest

    yeah Walter,

    I am talking about the "router ospf X network X.X.0.0 0.0.255.255 area
    0"-like statement

    It's just cisco way of refering to network mask? How about other
    routing protocols that cisco implement, do they use this notation as
    well?


    Walter Roberson wrote:
    > In article <>,
    > zibin <> wrote:
    > >why is ospf netmask needs to be in the form of 0.0.255.255, but not
    > >255.255.0.0? Was it just simple preference, or it has deeper reasons?

    >
    > Internally ospf uses 255.255.0.0 format.
    >
    > Are you perchance referring to the "router ospf" "network" statement?
    > If so, then it is cisco's standard notation on "network" statements,
    > not specific to protocol.
     
    zibin, Oct 30, 2006
    #3
  4. In article <>,
    zibin <> wrote:
    >yeah Walter,


    >I am talking about the "router ospf X network X.X.0.0 0.0.255.255 area
    >0"-like statement


    >It's just cisco way of refering to network mask? How about other
    >routing protocols that cisco implement, do they use this notation as
    >well?


    I do not have the time to check in detail, but the information I
    have found so far suggests that Yes, the standard Cisco notation
    for the 'router' sub-command 'network' is to use wildcard-masks
    rather than subnet masks.
     
    Walter Roberson, Oct 30, 2006
    #4
  5. zibin

    Slarmas Guest

    Its because of anding I think

    0 is exact match
    1 is match any

    Kind of like the inverse mask on an ACL

    Or I could be totally wrong.
    -------- Original Message --------

    > In article <>,
    > zibin <> wrote:
    >> yeah Walter,

    >
    >> I am talking about the "router ospf X network X.X.0.0 0.0.255.255 area
    >> 0"-like statement

    >
    >> It's just cisco way of refering to network mask? How about other
    >> routing protocols that cisco implement, do they use this notation as
    >> well?

    >
    > I do not have the time to check in detail, but the information I
    > have found so far suggests that Yes, the standard Cisco notation
    > for the 'router' sub-command 'network' is to use wildcard-masks
    > rather than subnet masks.
     
    Slarmas, Dec 10, 2006
    #5
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