06-02-2013 11:08 AM - edited 03-04-2019 08:04 PM
Hi All,
I was wondering why do L2 swicthes have a unique mac address on all switchports ? These addresses are not used for mac rewrite during L2 forwarding since these switches themselves are layer to transit switches. What are these mac addreses used for then ?
Thanks in advance
Regards
Umesh Shetty
Solved! Go to Solution.
06-02-2013 11:31 AM
Hi,
Have a look at this post for some of the answers:
https://learningnetwork.cisco.com/thread/28988
HTH
01-19-2015 02:53 PM
Under traditional 802.1D, a different mac address is used for every Spanning Tree Bridge ID (one Bridge ID is required per vlan.
Applicable to PVST+.
If you use Extended System ID to define the Bridge ID, then you don't need as many mac addresses because the vlan id will be used as the 12 bits in the Extended System ID, to make it unique from other Bridge IDs
06-02-2013 11:31 AM
Hi,
Have a look at this post for some of the answers:
https://learningnetwork.cisco.com/thread/28988
HTH
01-19-2015 02:53 PM
Under traditional 802.1D, a different mac address is used for every Spanning Tree Bridge ID (one Bridge ID is required per vlan.
Applicable to PVST+.
If you use Extended System ID to define the Bridge ID, then you don't need as many mac addresses because the vlan id will be used as the 12 bits in the Extended System ID, to make it unique from other Bridge IDs
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