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Forum Replies

  1. Hi K,

    The switch with the best bridge ID becomes the root bridge. The bridge ID consists of the priority (default value 32768) and the MAC address.

    With the default settings, it’s up to the MAC address to determine which switch will become root bridge. This applies to all VLANs.


  2. Hi Heng,

    You can configure a different priority for each VLAN, allowing you to select a different root bridge per VLAN.

  3. Hello Heng.

    If you do not change any of the priorities for root bridge selection, then by default the switch with the lowest bridge ID will be chosen. This means that the same switch will be chosen as the root bridge for all VLANs.

    I hope this has been helpful!


  4. Hi Zeko,

    You change it with the following command:

    SW1(config)#spanning-tree vlan 1 priority 4096

    Which sets the priority to 4096 for VLAN 1. This way, you can change it for each individual VLAN. You can also do this for a range:

    SW1(config)#spanning-tree vlan 1-200 priority 4096

    There’s also this command:

    SW1(config)#spanning-tree vlan 1 root primary

    You can use “primary” or “secondary”. Basically it’s a macro that checks for the current root bridge and then sets the priority of the switch to a value just above or below the current root bridge.

    By default, the

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