OSPF Area 0

Discussion in 'Cisco' started by Benson, Jun 19, 2004.

  1. Benson

    Benson Guest

    Hi,
    I have a network question:
    ( Area 12 )
    (subnet = 100.12.0.0/16)
    ((Some Routers)(area 11))
    |
    |
    |
    |
    |
    ((some routers )( Area10)) ----- ( Router R ) ------ ((some routers )(area 9))
    (subnet = 100.10.0.0/16) (subnet = 100.11.0.0/16)
    ( Area 10 ) ( Area 11 )


    They are running the OSPF routing protocols.

    How can I set up the area 0 for this network ? Area 0 including the R only ?
    so that

    Ospf 100
    network 100.10.0.0 0.0.255.255 area 0
    network 100.11.0.0 0.0.255.255 area 0
    network 100.12.0.0 0.0.255.255 area 0

    Am I right ? if not, how can I config the area 0 ?


    Thank you so much
    Benson
     
    Benson, Jun 19, 2004
    #1
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  2. Benson

    Benson Guest

    Hi Stephen,

    Thank you for your answer, in fact, I tried this configuration, any
    router can ping the others, since they form the adjacenies each other.
    But the workstations in any LAN of the routers can not ping the other
    workstations, and there is no Tcp/IP configuration problem ( Gateway,
    Subnet Mask..are correct ). Do you know why ?

    I did not configure the Area 0 in the diagram. ( sorry that, there are
    only area 10, 11, 12, and no area 9 in the diagram ), I also
    configured the loopback interface, of course ).

    Area 10, and 11 represents the two companies, and Area 12 is the ISP
    Area.

    How can I configure the OSPF area so that workstations in Area 10 can
    access the resources in Area 11 and 12, and vice versa.

    Thank you very much indeed.
    Benson




    "shope" <> wrote in message news:<hE1Bc.210$o35.21@newsfe5-win>...
    > "Benson" <> wrote in message
    > news:...
    > > Hi,
    > > I have a network question:
    > >
    > > (subnet = 100.12.0.0/16)
    > > ((Some Routers )( Area 12 ))
    > > |
    > > |
    > > |
    > > |
    > > |
    > > ((some routers )( Area10)) ----- ( Router R ) ------ ((some

    > routers )(area 11))
    > > (subnet = 100.10.0.0/16) (subnet =

    > 100.11.0.0/16)
    > >
    > >
    > >
    > > They are running the OSPF routing protocols.
    > >
    > > How can I set up the area 0 for this network ? Area 0 including the R only

    > ?
    > > so that
    > >
    > > Ospf 100
    > > network 100.10.0.0 0.0.255.255 area 0
    > > network 100.11.0.0 0.0.255.255 area 0
    > > network 100.12.0.0 0.0.255.255 area 0
    > >
    > > Am I right ? if not, how can I config the area 0 ?

    >
    > a single router can be a member of more than 1 area (ie is an ABR) - so long
    > as the list of areas include area 0.
    >
    > if all you have is a single router connecting all the areas, then that
    > router just needs an interface in area 0 - maybe just a loopback?
    >
    > the thing to watch is that OSPF cant "fix" a split of area 0 into sections -
    > area 0 needs to stay interconnected. Not an issue with your diagram, but may
    > get more complicated if you have resilient connections.
    >
    > >
    > >
    > > Thank you so much
    > > Benson
     
    Benson, Jun 20, 2004
    #2
    1. Advertising

  3. Benson

    Benson Guest

    Hi Stephen,

    Thank you for your answer, in fact, I tried this configuration, any
    router can ping the others, since they form the adjacenies each other.
    But the workstations in any LAN of the routers can not ping the other
    workstations, and there is no Tcp/IP configuration problem ( Gateway,
    Subnet Mask..are correct ). Do you know why ?

    I did not configure the Area 0 in the diagram. ( sorry that, there are
    only area 10, 11, 12, and no area 9 in the diagram ), I also
    configured the loopback interface, of course ).

    Area 10, and 11 represents the two companies, and Area 12 is the ISP
    Area.

    How can I configure the OSPF area so that workstations in Area 10 can
    access the resources in Area 11 and 12, and vice versa.

    Thank you very much indeed.
    Benson




    "shope" <> wrote in message news:<hE1Bc.210$o35.21@newsfe5-win>...
    > "Benson" <> wrote in message
    > news:...
    > > Hi,
    > > I have a network question:
    > >
    > > (subnet = 100.12.0.0/16)
    > > ((Some Routers )( Area 12 ))
    > > |
    > > |
    > > |
    > > |
    > > |
    > > ((some routers )( Area10)) ----- ( Router R ) ------ ((some

    > routers )(area 11))
    > > (subnet = 100.10.0.0/16) (subnet =

    > 100.11.0.0/16)
    > >
    > >
    > >
    > > They are running the OSPF routing protocols.
    > >
    > > How can I set up the area 0 for this network ? Area 0 including the R only

    > ?
    > > so that
    > >
    > > Ospf 100
    > > network 100.10.0.0 0.0.255.255 area 0
    > > network 100.11.0.0 0.0.255.255 area 0
    > > network 100.12.0.0 0.0.255.255 area 0
    > >
    > > Am I right ? if not, how can I config the area 0 ?

    >
    > a single router can be a member of more than 1 area (ie is an ABR) - so long
    > as the list of areas include area 0.
    >
    > if all you have is a single router connecting all the areas, then that
    > router just needs an interface in area 0 - maybe just a loopback?
    >
    > the thing to watch is that OSPF cant "fix" a split of area 0 into sections -
    > area 0 needs to stay interconnected. Not an issue with your diagram, but may
    > get more complicated if you have resilient connections.
    >
    > >
    > >
    > > Thank you so much
    > > Benson
     
    Benson, Jun 20, 2004
    #3
  4. Benson

    shope Guest

    "Benson" <> wrote in message
    news:...
    > Hi Stephen,
    >
    > Thank you for your answer, in fact, I tried this configuration, any
    > router can ping the others, since they form the adjacenies each other.
    > But the workstations in any LAN of the routers can not ping the other
    > workstations, and there is no Tcp/IP configuration problem ( Gateway,
    > Subnet Mask..are correct ). Do you know why ?
    >
    > I did not configure the Area 0 in the diagram. ( sorry that, there are
    > only area 10, 11, 12, and no area 9 in the diagram ), I also
    > configured the loopback interface, of course ).


    if you dont have an area 0, then OSPF is not going to work. if you want to
    use areas, then OSPF is required to have area 0.

    If you dont like that, then the alternatives are to alter the routers so
    that they are all in the same area, (easiest fix) or link the different
    areas by a different routing protocol and use route redistribution between
    say BGP and OSPF - it will get more complicated.

    every router connected to 2 or more areas must be connected to area 0, or no
    routes will propagate between the different routers in different areas.

    Have a look in the routing tables in each router, and see if they have
    routes for other areas besides the areas directly connected.
    >
    > Area 10, and 11 represents the two companies, and Area 12 is the ISP
    > Area.
    >
    > How can I configure the OSPF area so that workstations in Area 10 can
    > access the resources in Area 11 and 12, and vice versa.
    >
    > Thank you very much indeed.
    > Benson
    >
    >
    >
    >
    > "shope" <> wrote in message

    news:<hE1Bc.210$o35.21@newsfe5-win>...
    > > "Benson" <> wrote in message
    > > news:...
    > > > Hi,
    > > > I have a network question:
    > > >
    > > > (subnet = 100.12.0.0/16)
    > > > ((Some Routers )( Area 12 ))
    > > > |
    > > > |
    > > > |
    > > > |
    > > > |
    > > > ((some routers )( Area10)) ----- ( Router R ) ------ ((some

    > > routers )(area 11))
    > > > (subnet = 100.10.0.0/16) (subnet =

    > > 100.11.0.0/16)
    > > >
    > > >
    > > >
    > > > They are running the OSPF routing protocols.
    > > >
    > > > How can I set up the area 0 for this network ? Area 0 including the R

    only
    > > ?
    > > > so that
    > > >
    > > > Ospf 100
    > > > network 100.10.0.0 0.0.255.255 area 0
    > > > network 100.11.0.0 0.0.255.255 area 0
    > > > network 100.12.0.0 0.0.255.255 area 0
    > > >
    > > > Am I right ? if not, how can I config the area 0 ?

    > >
    > > a single router can be a member of more than 1 area (ie is an ABR) - so

    long
    > > as the list of areas include area 0.
    > >
    > > if all you have is a single router connecting all the areas, then that
    > > router just needs an interface in area 0 - maybe just a loopback?
    > >
    > > the thing to watch is that OSPF cant "fix" a split of area 0 into

    sections -
    > > area 0 needs to stay interconnected. Not an issue with your diagram, but

    may
    > > get more complicated if you have resilient connections.
    > >
    > > >
    > > >
    > > > Thank you so much
    > > > Benson

    --
    Regards

    Stephen Hope - return address needs fewer xxs
     
    shope, Jun 20, 2004
    #4
  5. Benson

    Benson Guest

    Hi, Stephen,

    I did it, thank you for your instruction.

    The two companies can access each other, after introducing the Area O
    into the network by adding a extra loopback interface in the Router R,
    but how to configure between the R and the ISP, since it is using BGP
    routing protocols.
    Let's say Area 12 uses AS#12, Area 11 uses AS#11, and Area 10 uses
    AS#10, so how can I configure the redistribution between the AS and
    Area.

    Thank you very much
    Benson



    "shope" <> wrote in message news:<0rkBc.260$>...
    > "Benson" <> wrote in message
    > news:...
    > > Hi Stephen,
    > >
    > > Thank you for your answer, in fact, I tried this configuration, any
    > > router can ping the others, since they form the adjacenies each other.
    > > But the workstations in any LAN of the routers can not ping the other
    > > workstations, and there is no Tcp/IP configuration problem ( Gateway,
    > > Subnet Mask..are correct ). Do you know why ?
    > >
    > > I did not configure the Area 0 in the diagram. ( sorry that, there are
    > > only area 10, 11, 12, and no area 9 in the diagram ), I also
    > > configured the loopback interface, of course ).

    >
    > if you dont have an area 0, then OSPF is not going to work. if you want to
    > use areas, then OSPF is required to have area 0.
    >
    > If you dont like that, then the alternatives are to alter the routers so
    > that they are all in the same area, (easiest fix) or link the different
    > areas by a different routing protocol and use route redistribution between
    > say BGP and OSPF - it will get more complicated.
    >
    > every router connected to 2 or more areas must be connected to area 0, or no
    > routes will propagate between the different routers in different areas.
    >
    > Have a look in the routing tables in each router, and see if they have
    > routes for other areas besides the areas directly connected.
    > >
    > > Area 10, and 11 represents the two companies, and Area 12 is the ISP
    > > Area.
    > >
    > > How can I configure the OSPF area so that workstations in Area 10 can
    > > access the resources in Area 11 and 12, and vice versa.
    > >
    > > Thank you very much indeed.
    > > Benson
    > >
    > >
    > >
    > >
    > > "shope" <> wrote in message

    > news:<hE1Bc.210$o35.21@newsfe5-win>...
    > > > "Benson" <> wrote in message
    > > > news:...
    > > > > Hi,
    > > > > I have a network question:
    > > > >
    > > > > (subnet = 100.12.0.0/16)
    > > > > ((Some Routers )( Area 12 ))
    > > > > |
    > > > > |
    > > > > |
    > > > > |
    > > > > |
    > > > > ((some routers )( Area10)) ----- ( Router R ) ------ ((some

    > routers )(area 11))
    > > > > (subnet = 100.10.0.0/16) (subnet =

    > 100.11.0.0/16)
    > > > >
    > > > >
    > > > >
    > > > > They are running the OSPF routing protocols.
    > > > >
    > > > > How can I set up the area 0 for this network ? Area 0 including the R

    > only
    > ?
    > > > > so that
    > > > >
    > > > > Ospf 100
    > > > > network 100.10.0.0 0.0.255.255 area 0
    > > > > network 100.11.0.0 0.0.255.255 area 0
    > > > > network 100.12.0.0 0.0.255.255 area 0
    > > > >
    > > > > Am I right ? if not, how can I config the area 0 ?
    > > >
    > > > a single router can be a member of more than 1 area (ie is an ABR) - so

    > long
    > > > as the list of areas include area 0.
    > > >
    > > > if all you have is a single router connecting all the areas, then that
    > > > router just needs an interface in area 0 - maybe just a loopback?
    > > >
    > > > the thing to watch is that OSPF cant "fix" a split of area 0 into

    > sections -
    > > > area 0 needs to stay interconnected. Not an issue with your diagram, but

    > may
    > > > get more complicated if you have resilient connections.
    > > >
    > > > >
    > > > >
    > > > > Thank you so much
    > > > > Benson
     
    Benson, Jun 21, 2004
    #5
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