Wired Intelligent Edge

Hi all,

I have a stack core switch dell N4032 and 4 HP 2530-48G-PoEP Switch where 2 are for data traffic and the other two are for VoIP. I also have 3 vlans configured (50, 70 and 250), if i connect the data switch number one y see this logs on the core:

<189> Jan 13 11:27:38 SWC-PATRICIOS-1 TRAPMGR[dot1s_task]: traputil.c(763) 2018754 %% Po2 is transitioned from the Forwarding state to the Blocking state in VLAN 250
<189> Jan 13 11:27:38 SWC-PATRICIOS-1 TRAPMGR[dot1s_task]: traputil.c(763) 2018753 %% Po2 is transitioned from the Learning state to the Forwarding state in VLAN 70
<189> Jan 13 11:27:38 SWC-PATRICIOS-1 TRAPMGR[dot1s_task]: traputil.c(763) 2018752 %% Po2 is transitioned from the Learning state to the Forwarding state in VLAN 50
<189> Jan 13 11:27:38 SWC-PATRICIOS-1 TRAPMGR[dot1s_task]: traputil.c(763) 2018751 %% Po2 is transitioned from the Forwarding state to the Blocking state in VLAN 70
<189> Jan 13 11:27:38 SWC-PATRICIOS-1 TRAPMGR[dot1s_task]: traputil.c(763) 2018750 %% Po2 is transitioned from the Forwarding state to the Blocking state in VLAN 50
<189> Jan 13 11:27:37 SWC-PATRICIOS-1 TRAPMGR[dot1s_task]: traputil.c(763) 2018749 %% Po2 is transitioned from the Learning state to the Forwarding state in VLAN 250

Here is the config on the dell core:

SWC-PATRICIOS#show running-config interface te1/0/1

channel-group 1 mode on
description "LAG SW1"
spanning-tree guard loop

SWC-PATRICIOS#show running-config interface te2/0/1

channel-group 1 mode on
description "LAG SW1"
spanning-tree guard loop

SWC-PATRICIOS#show running-config interface po1

description "Link to SWA-PATRICIOS-01"
spanning-tree guard loop
switchport mode general
switchport general allowed vlan add 2,50,70,250 tagged

SWC-PATRICIOS#show running-config interface po2

description "Link to SWA-PATRICIOS-02"
switchport mode general
switchport general allowed vlan add 2,50,70,250 tagged

I am observing that the root bridge is being SWA-PATRICIOS-01 (data switch 1) however the priority of STP is lower in the core dell.

Do you have any idea why this can happen?

PD: The LAG configuration on the Dell stack is static, while on aruba switches it is LACP, can this be related to the problem?

Regards!

Do you have a diagram of the connectivity?

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@jvivas wrote:

 

PD: The LAG configuration on the Dell stack is static, while on aruba switches it is LACP, can this be related to the problem?

 

Regards!

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Yes, if one side is static and the other is dynamic, it's likely the port channel is not forming and consequently creating the loop.

Hi cclemmer,

Thanks for the reply. Yes, the devices are connected as the picture shows.

Thanks for the diagram.

Yes based on that, please ensure the same port channel technology on each end of the links to prevent loops. Either static on both sides, or LACP on both sides (recommended).

Thank you very much cclemmer,

This may also be causing swa-patricios-01 not to take the priorities of stp of the core?.

Regards,

I just noticed the prioritty question in your original post.

Please ensure that both the Dell and Aruba switches are running the same version of STP. There's not enough information from the config shared to say for sure that's the problem, but that's what I would check first.

What STP are you using? If both have MSPT make sure all the relevant settings are similar o nthe Dell and Aruba switches. I'd recommend RSTP as it's easier to configure and you're not going to need to do load balancing with STP in that topology

Both are using RPVST, annex configuration information:

Dell stack:

SWC-PATRICIOS # show spanning-tree

Spanning Tree: Enabled - BPDU Flooding: Disabled - Portfast BPDU Filtering: Disabled
Mode: rstp
CST Regional Root: 20: 00: E4: F0: 04: 92: 70: CB
Regional Root Path Cost: 0
ROOT ID
              Priority 8192
              Address E4F0.0492.70CB
              Path Cost 0
              Root port
              Hello Time: 2s Max Age: 20s Forward Delay: 15s Transmit Hold Count: 6s
              Bridge Max Hops: 20

Aruba access switch:

SWA-PATRICIOS-01 # show spanning-tree

 Spanning Tree Information

  STP Enabled [No]: Yes
  Mode: RPVST
  Extended System ID: Enabled
  Ignore PVID Inconsistency: Disabled
  RPVST Enabled VLANs: 1-2,44,46,50,70,250
  MAC Address Switch: 94f128-466840
  Root Guard Ports:
  Loop Guard Ports:
  TCN Guard Ports:
  BPDU Protected Ports:
  BPDU Filtered Ports:
  Auto Edge Ports: 3-52, Trk1
  Admin Edge Ports:

I understand that I need to configure the priority on each vlan for RPVST, however SWA-PATRICIOS-01 is still the root bridge.

Any idea why this happens?

Regards,

use mode RSTP on Aruba too

Hi, how are you?

I still have the problem, the teams are running RPVST but still taking the SWA-PATRICIOS-01 as a root bridge, even though the priority of the SW-CORE is lower.

Any idea what it could be?

Regards,

What your configuration now ?