catalyst 2950 vlan problem

Discussion in 'Cisco' started by Rick, Nov 27, 2003.

  1. Rick

    Rick Guest

    I defined 2 vlans on my catalyst which has 12 ports.
    I assigned a IP to the default VLAN management interface
    that is vlan1.
    then I Created a vlan2 and I put the port 10 11 and 12 to the vlan2
    so that I have:

    vlan1 -> ports 1 2 3 4 5 6 7 8 9
    vlan2 -> ports 10 11 12

    I assigned an IP Address to vlan2.
    I WAnt vlan1 and vlan 2 to being attached to different networks
    separated from each other like having 2 different switches.

    the problem is that vlan2 is always set as shutdown.
    I can only have it avaliable if I set vlan2 as the default management interface
    but in this way vlan1 is automatically set as shutdown.
    That is I Cannot have 2 different vlans with 2 different IP addresses
    assigned to them and having the 2 different IP working at the same
    time, one of the 2 interfaces (THe one which is not the management interface)
    is put in shutdown.
    The IP Addresses belong to different networks and are 2 different class B
    is this behaviour normal ?
    the 2 vlans are working anyway as 2 different broadcast domains but
    only one of them is pingable since only one of them is "no shutdown"
    and that is the default management vlan interface.
    is there some way to fix it?

    Rick, Nov 27, 2003
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  2. Rick

    Andy Furnell Guest

    You've hit the nail on the head. The VLAN interface on the 2950 is a
    MANAGEMENT interface, not a router interface. You can (and should) have
    only one management interface, which should ideally be in its own VLAN
    far away from potential broadcast storms from machines on the switch,
    which could flood the CPU on the switch. If you need to manage the switch
    from both subnets without routing traffic from one to another you will
    need to dual-home your management systems into both VLANs (which has
    certain security implications, as I'm sure you're aware :)
    You will need to use a routing device to route between the two subnets
    in the two discrete VLANs. This can be a 2+ port ethernet router, a 1 port
    vlan-capable ethernet router, or a switch with routing capabilities (I
    believe a 2950 running an EI will do this).


    Andy Furnell, Nov 27, 2003
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  3. Rick

    Steve Wyles Guest


    This is normal behaviour, the IP address is only for management
    purposes and nothing else. Although the 2950 runs IOS, remember it is a
    switch and not a router.

    Steve Wyles, Nov 27, 2003
  4. Rick

    joe Guest

    You really bought the wrong switch. Go buy a 3550 smi for what your
    trying to do here. EMI if you want bgp and other routing protocols.

    the 3550 is like a high tech, powerful router with vlan interfaces,
    I consider mine a mini cat6k with msfc.
    joe, Nov 28, 2003
  5. thanks all for the answers.
    I REally do not want to route between interfaces.
    I just want to have 2 different VLANS mapped on different ports
    to detach 2 different networks in a way they
    cannot see each other.
    So now I know I Can only have 1 management interface

    thanks you

    Riccardo Veraldi, Nov 28, 2003
  6. Yes.


    M.C. van den Bovenkamp, Nov 28, 2003
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