Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Cat 4500 IOS Ver 12.1.19EW1 Spanning-tree

why do the command:

switch(config)#spanning-tree vlan 1 root primary

not set the value 8192 on the bridge priority.

example:show spanning-tree

VLAN0001 Spanning tree ieee

Root ID Priority 24577

1 ACCEPTED SOLUTION

Accepted Solutions

Re: Cat 4500 IOS Ver 12.1.19EW1 Spanning-tree

Hi,

isn't extended system ID enabled on your 4500?

I've found following for Cat2950 (http://www.cisco.com/univercd/cc/td/doc/product/lan/cat2950/1219ea1/scg/swstp.pdf):

"For Catalyst 2950 switches with the extended system ID (Release 12.1(9)EA1 and later), if all network devices in VLAN 20 have the default priority of 32768, entering the spanning-tree vlan 20 root primary command on the switch sets the switch priority to 24576, which causes this switch to become the root switch for VLAN 20.

For Catalyst 2950 switches without the extended system ID (software earlier than Release 12.1(9)EA1), if all network devices in VLAN 100 have the default priority of 32768, entering the spanning-tree vlan 100 root primary command on the switch sets the switch priority for VLAN 100 to 8192, which causes this switch to become the root switch for VLAN 100."

So I think this might be the same case.

Regards,

Milan

2 REPLIES

Re: Cat 4500 IOS Ver 12.1.19EW1 Spanning-tree

Hi,

isn't extended system ID enabled on your 4500?

I've found following for Cat2950 (http://www.cisco.com/univercd/cc/td/doc/product/lan/cat2950/1219ea1/scg/swstp.pdf):

"For Catalyst 2950 switches with the extended system ID (Release 12.1(9)EA1 and later), if all network devices in VLAN 20 have the default priority of 32768, entering the spanning-tree vlan 20 root primary command on the switch sets the switch priority to 24576, which causes this switch to become the root switch for VLAN 20.

For Catalyst 2950 switches without the extended system ID (software earlier than Release 12.1(9)EA1), if all network devices in VLAN 100 have the default priority of 32768, entering the spanning-tree vlan 100 root primary command on the switch sets the switch priority for VLAN 100 to 8192, which causes this switch to become the root switch for VLAN 100."

So I think this might be the same case.

Regards,

Milan

New Member

Re: Cat 4500 IOS Ver 12.1.19EW1 Spanning-tree

Hi Milan

thanks for information.

we have the solution for our problem.

Yours sincerely

Roland Marti

160
Views
0
Helpful
2
Replies