cisco dot1q and 2 routers

Discussion in 'Cisco' started by jmize@dickinsonwright.com, Jun 19, 2004.

  1. Guest

    I have 2 extreme switches,
    beetween them i have 2 2621 cisco routers.
    if the to switches are connected together with out the router i can
    pass vlan 150.
    by placing the vlan 150 on the 2 ports connectint the switches.th
    evlan 150 will follow the path set port to port. i had hope the same
    would work with the cisco routers.
    if i place 2 2621 routers between them i cannot. i tried the following
    config

    r1
    fas 0/0
    ip address 10.10.1.241 255.255.0.0
    fas 0/0.150
    encap dot1q 150

    fas 0/1
    ip address 10.100.110.10 255.255.255.0
    fas 0/1.150
    encap dot1q 150

    r2

    fas 0/1
    ip address 10.100.110.11 255.255.255.0
    fas 0/1.150
    encap dot1q 150

    fas 0/0
    ip address 10.11.1.241 255.255.0.0
    fas 0/0.150
    encap dot1q 150

    If i place an ipaddress from my vlan 150 (10.150.0.10) on the fas 0/0
    of R1 i can ping it from a user on vlan 150, so i can see the router
    picking up the packest on the first interface. just cannot get the
    vlan to pass through the router.
    Jeff
     
    , Jun 19, 2004
    #1
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  2. Bill F Guest

    the subints need ip addresses.
     
    Bill F, Jun 19, 2004
    #2
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  3. Hansang Bae Guest

    In article <>,
    says...
    > I have 2 extreme switches,
    > beetween them i have 2 2621 cisco routers.
    > if the to switches are connected together with out the router i can
    > pass vlan 150.
    > by placing the vlan 150 on the 2 ports connectint the switches.th
    > evlan 150 will follow the path set port to port. i had hope the same
    > would work with the cisco routers.
    > if i place 2 2621 routers between them i cannot. i tried the following
    > config
    >
    > r1
    > fas 0/0
    > ip address 10.10.1.241 255.255.0.0
    > fas 0/0.150
    > encap dot1q 150
    >
    > fas 0/1
    > ip address 10.100.110.10 255.255.255.0
    > fas 0/1.150
    > encap dot1q 150
    >
    > r2
    >
    > fas 0/1
    > ip address 10.100.110.11 255.255.255.0
    > fas 0/1.150
    > encap dot1q 150
    >
    > fas 0/0
    > ip address 10.11.1.241 255.255.0.0
    > fas 0/0.150
    > encap dot1q 150
    >
    > If i place an ipaddress from my vlan 150 (10.150.0.10) on the fas 0/0
    > of R1 i can ping it from a user on vlan 150, so i can see the router
    > picking up the packest on the first interface. just cannot get the
    > vlan to pass through the router.


    Kind of confusing as to what you're trying to do. But if you put an IP
    on the major interface (Fa0/1 for example), it will not be tagged with
    the dot1q header. In Cisco-speak, this is called the native VLAN and
    native VLANs are not tagged with dot1q unless you explicitly tell the
    switch to do so. Also remember that dot1q is only a L2 animal. Routers
    do not forward along dot1q headers.

    --

    hsb

    "Somehow I imagined this experience would be more rewarding" Calvin
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    Hansang Bae, Jun 19, 2004
    #3
  4. Gordon Smith Guest

    What are you trying to achieve?
    From your description, you are wanting to use the routers as bridges only.

    When tagging interfaces, don't assign an IP address to the primary interface
    e.g.
    r1
    fas 0/0
    no ip address
    fas 0/0.150
    ip address 10.10.1.241 255.255.0.0
    encap dot1q 150


    Don't confuse layer 2 and layer 3. You may find it helpful to review the OSI
    model then re-visit the problem
     
    Gordon Smith, Jun 19, 2004
    #4
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