06-02-2013 06:28 PM - last edited on 03-25-2019 04:24 PM by ciscomoderator
Hello
I read that there is a limit of 128 spanning-tree instances per switch if using PVST, and that any instances greater than 128 do not us spanning-tree.
Does the switch indicate that the 128-instance limit has been reached? Or do you just need to determine this by using SHOW SPANNING-TREE XXXX commands?
Thanks
Solved! Go to Solution.
06-02-2013 07:05 PM
Hi,
Not sure exactly what the error message would be if you try to configure more then 128 instances, but if you are planning to have 129 instances, you would need to delete one of the existing instance before you can add the 129th instance.
sh span-tree will show you one vlan per instance, but the numbers don't necessary corelate For example: if you have 2 instances in your switch, the vlans for these instance can be 250 and 270.
HTH
06-02-2013 07:05 PM
Hi,
Not sure exactly what the error message would be if you try to configure more then 128 instances, but if you are planning to have 129 instances, you would need to delete one of the existing instance before you can add the 129th instance.
sh span-tree will show you one vlan per instance, but the numbers don't necessary corelate For example: if you have 2 instances in your switch, the vlans for these instance can be 250 and 270.
HTH
06-02-2013 07:13 PM
HI,
In PVST+ or rapid-PVST+ mode, the switch or switch stack supports up to 128 spanning-tree instances.
In MSTP mode, the switch or switch stack supports up to 65 MST instances. The number of VLANs that can be mapped to a particular MST instance is unlimited
cmd:
sh spanning-tree summary totals
Below you can see the instance active for vlans.
also you get the following error message if 128 instances are over:
***** Platform limit of 128 STP instances exceeded. No instance created for VLAN190
Ref:
http://ieoc.com/forums/p/5975/20666.aspx
HTH
Regards
Inayath
*Plz rate all usefull posts.
06-02-2013 08:01 PM
Hi Reza
Yes you will see the platform limit error message when you cross your STP instance.
######Platform limit of 128 STP instances exceeded
Thanks & Regards
Sandeep
06-03-2013 06:11 PM
Thank you all!
I selected the first response, even though you all gave great info.
Not sure how to 'share' the correct answer.
Cliff
06-03-2013 10:37 PM
Hi Clifford,
Its already marked answered.
Regards
Inayath
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