Limit active vlan on spanning tree cisco catalyst

Hati-hati terhadap masalah spanning tree pada Cisco Catalyst karena memiliki limit tersendiri di dalam spanning tree dalam menangani jumlah vlan active, Case ini saya temukan di Catalyst 3550 dan 2940.

Untuk default maximum active vlan dalam spanning tree yang dapat di tangani adalah :
- Catalyst 3550 = 128
- Catalyst 2940 = 64

Effect dari limitasi vlan tersebut maka akan terjadi pemblokiran pada interface yang terdapat spanning tree di dalamnya. Akan muncul log sebagai berikut :

PANTREE_VLAN_SW-2-MAX_INSTANCE: Platform limit of [dec] STP instances
exceeded. No instance created for [chars] (port [chars]).


Untuk mengatasinya tinggal menghilangkan beberapa vlan active dari spanning tree tersebut. Untuk meluhat jumlah vlan dalam spanning tree :

# show spanning-tree summary

Output perintah tersebut di paling bawah akan terlihat jumlah dari vlan active dalam spanning tree tersebut.

Untuk mengatasinya tinggal menjalankan perintah berikut :

Router (config)#no spanning-tree vlan xxx

xxx = vlan id

Berikut info dari Web Cisco :

SPANTREE_VLAN_SW Messages

The following are Spanning Tree VLAN Switch messages.

Error Message

%SPANTREE_VLAN_SW-2-MAX_INSTANCE : Number of STP instances has reach platform limit of [dec] instances. Unable to create the newly created instace since [chars] ( port [chars])

Explanation The number of currently active VLAN spanning tree instances has reached a platform-specific limit. No additional VLAN instances will be created until the number of existing instances drops below the platform limit. The message text shows the smallest VLAN number of those VLANs that are unable to have STP instances created.

Recommended Action Reduce the number of currently active spanning tree instances by either disabling some of the currently active spanning tree instances or deleting the VLANs associated with currently active spanning tree instances. You will have to manually enable the spanning trees that could not be created due to limited instances.

Mudah-mudahan bermanfaat.


Dony Ramansyah
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