Reg:Spanning tree protocol

Hi All,

I just want to know what is the mac address stp process used in any switch such as 3550/3560.Is this the mac address of any interface or any board address.

Please help.

Thanks

 

 

Comments

  • Source MAC for a BPDU is the mac-address of egress port on the switch.

    Destination MAC depends on the trunking encapsulation and native VLAN.

     

    If the switch is running PVST+ and native VLAN is VLAN 1,

    destination mac for all VLANs (including VLAN 1) is 0100.0ccc.cccd (Cisco prorietary STP address)

    Additionally, VLAN 1 BPDUs are also sent to IEEE STP Address (0180.c200.0000)

    In the above case, VLAN1 BPDUs will be sent twice. Once to Cisco address and once to IEEE address. They will be sent untagged both times.

     

    If the switch is running PVST+ and native VLAN is not 1

    destination mac for all VLANs (including VLAN 1 and native VLAN) is 0100.0ccc.cccd (Cisco prorietary STP address)

    Additionally, VLAN 1 BPDUs are also sent to IEEE STP Address (0180.c200.0000) on native VLAN untagged

    This is because, IEEE STP does not support Per VLAN BPDUs and Cisco uses VLAN 1 BPDUs for IEEE STP.

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