STP instance error

[jackzhao]

HI:

we have C3650-TD-E running in our datacenter since last year ( it was C3560-E24TD before the replacement)

when i try to add new vlan 670,  it shows

%SPANTREE_VLAN_SW-2-MAX_INSTANCE: Platform limit of 128 STP instances exceeded. No instance created for VLAN670 

then, the whole switch goes to a strange status,  when try to execute some command (like show run/show vlan/no vlan 670), it will get into totally no respond , even with console. some command is wokring(like show proc cpu/show vtp summary),

But the network seems working ( i'm not sure, can't take the risk), i have to reboot the whole switch.

After the reboot, it backs to normal, but when i try to add/remove vlan , it will come to same status, no respond

This 3650 is running with ios 16.6.3 , is this some kind of BUG? how can i solve this?

Please help

Thanks

[balaji.bandi]

i am thinking this may be bug look at the below one :

https://bst.cloudapps.cisco.com/bugsearch/bug/CSCux63710/?rfs=iqvred

[jackzhao]

thanks. but it shows fixed since ios 16.3, our device is running with 16.6 ，it should not be same issue 

[balaji.bandi]

also, the platform limitation as suggested in the post, best as suggest make it transparent and do the necessary changes?

another question, do you really have 128 VLANS ? in the network ?

[jackzhao]

Hi

it is running in transparent mode now, and these vlans were there before i joined this company. Maybe some are nolonger used, but I'm not sure.

The problem is when i try to add/remove vlan, it will come to no respond. just want to know how to solve this

[Reza Sharifi]

Hi,

Can you change the vtp to transparent mode and try again?

config t

vtp mode transparent

Also, 128 is the usually the limitation of the platform

Supported Spanning-Tree Instances

In PVST+ or Rapid PVST+ mode, the switch or switch stack supports up to 128 spanning-tree instances.

Link

https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst2960x/software/15-0_2_EX/layer2/configuration_guide/b_lay2_152ex_2960-x_cg/b_lay2_152ex_2960-x_cg_chapter_0110.html

HTH

[jackzhao]

Hi,

This device is running in transparent mode now，

Thanks