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New Member

How to disable PVST on catalyst switch?

Greetings,

How to disable PVST on catalyst switch (w/o enabling MultipleSTP)? In the other words, I want STP works on catalyst switch exactly as on standard non-cisco switch (mono spanning tree).

Best regards,

Dmitry N. Hramtsov

7 REPLIES
Cisco Employee

Re: How to disable PVST on catalyst switch?

In cat OS, you can use disable STP for all VLANs using

Console> (enable) set spantree disable ?

all Disable spanning tree all

mistp-instance Disable MISTP instances

VLAN numbers for PVST+/RAPID-PVST+

In IOS based switched, you can use

Router#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Router(config)#no spanning-tree vlan ?

WORD vlan range, example: 1,3-5,7,9-11

Router(config)#no spanning-tree vlan 1-1005

Router(config)#

But I do not understand what you would be achieving by disabling STP

New Member

Re: How to disable PVST on catalyst switch?

I do not want disable STP at all. What I want is just disable PVST extension. I want what my catalyst (3550 with EMI IOS) works just as non-cisco cheap switch (with mono STP like IEEE 802.1q requires).

Is it possible to configure catalyst in this manner?

Thanks for any help.

New Member

Re: How to disable PVST on catalyst switch?

Since where is no sulition offered and documentation has no answer about that, I conclude that it is impossible to configure catalyst switch in the way I want. Dolefully.

Please correct me if I am wrong.

In any case, thanks to people who tried to help.

New Member

Re: How to disable PVST on catalyst switch?

Hello.

802.1q can be enabled on trunks. This is, however, dependant on your hardware. "show port cap" will let you know if the line card supports 802.1q.

On CATOS the following command sets port 1/1 to trunk mode , trunk carries vlan 10 and uses dot1q.

set trunk 1/1 desirable 10 dot1q

On Native IOS it would be:

interface FastEthernet0/1

switchport trunk encapsulation dot1q

switchport mode trunk

no ip address

-Rob

New Member

Re: How to disable PVST on catalyst switch?

Thank you for your answer, but it is not answer to my question. :)

I want to disable PVST extension, i.e. I want that catalyst will not send BPDUs to VLANs except BPDUs version 0 to native VLAN like IEEE 802.1Q requires. Many other non-cisco switches (for example Allied Telesyn switches, Intel switches and many others) works this way.

Is it possible to configure catalyst switch for this behavior?

New Member

Re: How to disable PVST on catalyst switch?

I thought that was too easy ;-)

I beleive my answer is accurate however. (Hopefully someone will correct me if I am wrong.)

By using dot1q you define a unique spanning tree instance running on the native VLAN for all the VLANs in the network.

In terms of BPDUs, I beleieve verison is always 0 on both TC and Configuration BPDUs.

-Rob

New Member

Re: How to disable PVST on catalyst switch?

The command:

#sh spanning-tree mst

% Switch is not in mst mode

can help you to see if using Multiple spanning trees.

And, entering the msd config mode can help you

to disable mst:

MINIC01S(config)#spanning-tree mst conf

MINIC01S(config-mst)#?

abort Exit region configuration mode, aborting changes

exit Exit region configuration mode, applying changes

instance Map vlans to an MST instance

name Set configuration name

no Negate a command or set its defaults

private-vlan Set private-vlan synchronization

revision Set configuration revision number

show Display region configurations

To use only BPDU on a specific VLAN on the router

you can use:

interface FastEthernet0/1.1

description LAN 1 MANAGEMENT

encapsulation dot1Q 1 native

Best Regards

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