Catalyst 3750-E

[Less Santine]

Hello friends,

I need some help.

I have Sw 3750-E on the network and a Dell N3024F when I connect some equipment to the switch, Dell Sw tries to take root as root being Cisco.
In that attempt I have a drop in the network.

One thing I came across that the cyst is set to: mode pvst and Dell like: mode rstp

[johnd2310 · Accepted solution]

Hi,

If you are in a multi-vendor environment you should use mstp (multiple spanning tree protocol). Convert the cisco 3750 and the dell n3024f to use mstp. Have a look at the following doc on configuring mstp on the 3750e:

http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750e_3560e/software/release/12-2_40_se/configuration/guide/scg/swmstp.pdf

Thanks

John 

[Less Santine]

Can the protocol configuration be causing this failure, where does Dell try to take root?
This case is critical any new physical thing entering the network affects my mssql cluster

[Joseph W. Doherty]

Dell's RSTP might be incompatible with Cisco rapid-pvst.

John suggested MST - a version that should work with both.

[Less Santine]

Friend, I clicked the wrong button.

Setup is already set up

CISCO
#sh running-config
spanning-tree mode pvst
spanning-tree extend system-id
spanning-tree vlan 100 priority 4096

DELL
#sh running-config
spanning-tree priority 16384
spanning-tree vlan 1 priority 16384

And my problem persists

[Reza Sharifi]

Can you verify?

Are you using vlan 1 or vlan 100?

spanning-tree vlan 100 priority 4096

Also, the mode in Cisco is still pvst

HTH

[Less Santine]

The root of the network is Cisco.

#sh switch
Switch/Stack Mac Address : 8843.e1d5.d980
H/W Current
Switch# Role Mac Address Priority Version State
----------------------------------------------------------
*1 Master 8843.e1d5.d980 1 1 Ready
2 Member 0023.33a0.3580 1 1 Ready

I have not yet applied the changes I am in a productive environment.

[Reza Sharifi]

Please don't apply any of these changes during production hours.  It should be done during off hours. 

The output you posted has nothing to do with spanning tree. This output is simply showing that you have 2 switches in a stack with one being master and the other one member. Can you post the output of "sh spanning-tree" form both Dell and Cisco switches?

HTH

[Less Santine]

Yes.
Attached

[Reza Sharifi · Accepted solution]

Hi,

You can change the mode to rstp on the Cisco switch to match the Dell switch.

If you want the Cisco to be the root, lower the priority to be less then the Dell switch for the vlan you are using:

example:

config t

spanning-tree mode rapid-pvst

spanning-tree vlan xx priority 4096 

HTH