BPDU mac address are not in the table? ???

CCIE_2011

Hi all ....
i was setting up a lab here a while ago, to practice some spanning tree commands. type show span
and the root address is 0018.X.X. i took address and try to find out where it is coming from? which port? I typed show mac-add address 0018.X.X and i no entry for this address? ????
(PS:I know you can find root port with the same show span).

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Comments

Netstudent

Did you search for 01-80-C2-00-00-00? If so, then that is the multicast address. If you did indeed search for the MAC of the root bridge, then I would think it has to be in there somewhere.

dtlokee

They are there but the switch offsets the MAC address taht it uses to send the BPDUs by the interface # so if the base mac address is 0010.ABCD.0080 and you're connected to port 1 the source MAC of the port 0010.ABCD.0081 and port 11 woud be 0010.ABCD.008B.

CCIE_2011

dtlokee wrote:

They are there but the switch offsets the MAC address taht it uses to send the BPDUs by the interface # so if the base mac address is 0010.ABCD.0080 and you're connected to port 1 the source MAC of the port 0010.ABCD.0081 and port 11 woud be 0010.ABCD.008B.

Thanks alot .... you are totally true

Aquabat [banned]

what's ur name? is 2011 the year you want to get your ccie?

cisco_trooper

CCIE_2011 wrote:

dtlokee wrote:

They are there but the switch offsets the MAC address taht it uses to send the BPDUs by the interface # so if the base mac address is 0010.ABCD.0080 and you're connected to port 1 the source MAC of the port 0010.ABCD.0081 and port 11 woud be 0010.ABCD.008B.

Thanks alot .... you are totally true

Yea, he got his CCIE number so now he thinks he knows everything....

darkuser

http://www.cisco.com/univercd/cc/td/doc/product/rtrmgmt/sw_ntman/cwsimain/cwsi2/cwsiug2/vlan2/stpapp.htm