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Notable Replies

  1. system says:

    I really appreciate your efforts :slight_smile:

  2. Hi John,

    When you mix access and trunk mode, we get to see this message:

    SwitchA#
    %SPANTREE-7-RECV_1Q_NON_TRUNK: Received 802.1Q BPDU on non trunk FastEthernet0/14 VLAN1.
    %SPANTREE-7-BLOCK_PORT_TYPE: Blocking FastEthernet0/14 on VLAN0001. Inconsistent port type.
    %SPANTREE-2-UNBLOCK_CONSIST_PORT: Unblocking FastEthernet0/14 on VLAN0001. Port consistency restored.

    The trunk will send BPDUs for each VLAN, our access mode interface only sends one BPDU so that's why CDP reports this error. This won't be a working trunk but I think the access mode VLAN (VLAN1) will work.

    I'd have to give this a try to see if it works.

    Rene

  3. Dear Rene

    i'm new here i finished before some week from CCNA I want to study CCNP with you the explanation is very good.this command:

    switchport trunk encapsulation dot1q

    Is not working in my packet tracer how can I make a switching lab ??

  4. Hi Mohamed,

    There are two trunking protocols, 802.1q and ISL. Some newer switches only support 802.1Q and in that case this command will be unavailable.

    It's also possible that packet tracer doesn't support it, it's a simulator after all. It doesn't matter too much though...when this command doesn't work then the switch will use 802.1Q when you configure the interface as a trunk.

    Rene

  5. Nicholas,
    Your left hand side description is correct. Since the incoming tag matches the native vlan of the trunk, the tag gets discarded. I suspect, however, that your scenario would break if you told your switch "switchport trunk native vlan tag" which means that even the native vlan keeps the tag. Since almost all PCs have no idea what a vlan tag is, it would discard the packet.

    For your right hand side, I suspect the problem is not knowing what the access port VLAN is for connection from Switch 5 to Switch 6. If it is not vlan 10, this would explain the failure.

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