Nexus logs %STP-2-DISPUTE_CLEARED: and %STP-2-DISPUTE_DETECTED:

[Alexandre11]

Nexus show me messages like:

2019 Nov 25 16:16:31 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0834.
2019 Nov 25 16:16:31 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0903.
2019 Nov 25 16:16:31 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0908.
2019 Nov 25 16:16:33 MIN-NX5548-CIMA %STP-2-DISPUTE_DETECTED: Dispute detected on port port-channel4 on VLAN0899.
2019 Nov 25 16:16:37 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0899.
2019 Nov 25 16:17:03 MIN-NX5548-CIMA %STP-2-DISPUTE_DETECTED: Dispute detected on port port-channel4 on VLAN0805.
2019 Nov 25 16:17:07 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0805.
2019 Nov 25 16:17:09 MIN-NX5548-CIMA %STP-2-DISPUTE_DETECTED: Dispute detected on port port-channel4 on VLAN0905.
2019 Nov 25 16:17:11 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0905.
2019 Nov 25 16:17:35 MIN-NX5548-CIMA %STP-2-DISPUTE_DETECTED: Dispute detected on port port-channel4 on VLAN0805.
2019 Nov 25 16:17:35 MIN-NX5548-CIMA %STP-2-DISPUTE_DETECTED: Dispute detected on port port-channel4 on VLAN0834.
2019 Nov 25 16:17:37 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0805.
2019 Nov 25 16:17:37 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0834.
2019 Nov 25 16:19:15 MIN-NX5548-CIMA %STP-2-DISPUTE_DETECTED: Dispute detected on port port-channel4 on VLAN0805.
2019 Nov 25 16:19:17 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0805.
2019 Nov 25 16:20:13 MIN-NX5548-CIMA %STP-2-DISPUTE_DETECTED: Dispute detected on port port-channel4 on VLAN0900.
2019 Nov 25 16:20:13 MIN-NX5548-CIMA %STP-2-DISPUTE_DETECTED: Dispute detected on port port-channel4 on VLAN0901.
2019 Nov 25 16:20:17 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0900.
2019 Nov 25 16:20:17 MIN-NX5548-CIMA %STP-2-DISPUTE_DETECTED: Dispute detected on port port-channel4 on VLAN0834.
2019 Nov 25 16:20:19 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0834.
2019 Nov 25 16:20:19 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0901.
2019 Nov 25 16:20:27 MIN-NX5548-CIMA %STP-2-DISPUTE_DETECTED: Dispute detected on port port-channel4 on VLAN0805.
2019 Nov 25 16:20:31 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0805.

What is it ? Could you help me ?

[balaji.bandi]

If you can post your topology and configuration to understand what device version is this running  ?

or look at this post :

https://community.cisco.com/t5/switching/what-is-the-mean-quot-stp-2-dispute-detected-quot/td-p/1358325

[Alexandre11]

[n-kirillov]

Hi Alexandre!

In my environment to catch erroneus device I'm using ethanalyzer with option vlan number && stp to find mac address and investigate the problem.

[Sergiu.Daniluk]

Hi @Alexandre11 

Disputes usually means that a switch receives an inferior BPDU with designated role and state forwarding (or learning).  To exemplify this problem let’s take this scenario:

SwitchA is the root, so it will send a superior bpdu. For whatever reasons, the SBPDU will not reach switch B. Because of that, SwB will send a BPUD with it’s own information about root bridge which is an inferior BPDU (let’s say it marks himself as root), and will put the port to SwA in designated / forwarding state. SwA understands that SwB does not reaction to his BPDU so it will create a dispute (will put the port in blocking state to avoid loops).

In your case, you need to look at the switch connected on Po4, and see what is the STP state there.

Stay safe,

Sergiu

[joseponceiii]

@Alexandre11 Have you resolved the problem? We've been seeing this error on Nexus 9Ks connected to a 3650 switch. 

2021 Jan 19 23:26:02 N9K-1 %STP-2-DISPUTE_CLEARED: Dispute resolved for port Ethernet1/36 on VLAN0117.
2021 Jan 19 23:29:45 N9K-1 %STP-2-DISPUTE_DETECTED: Dispute detected on port Ethernet1/36 on VLAN0400.
2021 Jan 19 23:29:46 N9K-1 %STP-2-DISPUTE_CLEARED: Dispute resolved for port Ethernet1/36 on VLAN0400.

Any found solution?

Thanks in advance.

[Sergiu.Daniluk]

Hi @joseponceiii 

Have you checked the STP state for the disputed vlans on the 3650? What do you see there?

Cheers,

Sergiu

[joseponceiii]

@Sergiu.Daniluk Port roles/states are currently working as normal - N9K as root switch. Wasn't able to see the "dispute" states since it will be resolved quickly as you can see on the logs. However, it seems to be these errors appear in random/intermittent and SFPs were also changed. TAC suggested to upgrade the IOS of 3650s and looks it improved, but it seems the errors are still appearing. What other possible solution/reason for this? 

Thanks.

[AlexandreOppermann]

I solve my problem in the nexus, example:

show me this message:

2021 Jul 8 21:40:18 MIN-NX5548-CIMA %STP-2-DISPUTE_DETECTED: Dispute detected on port port-channel4 on VLAN0549.
2021 Jul 8 21:40:21 MIN-NX5548-CIMA %STP-2-DISPUTE_CLEARED: Dispute resolved for port port-channel4 on VLAN0549.

MIN-NX5548-CIMA(config)# no vlan 549
MIN-NX5548-CIMA(config)# vlan 549
MIN-NX5548-CIMA(config-vlan)# mode fabricpath
MIN-NX5548-CIMA(config-vlan)# name link-radio
MIN-NX5548-CIMA(config-vlan)# exit