Cisco SG350, trying to add another switch (BPDU Guard disabled port)

[DigitalManiak3k]

A couple of years ago, an MSP installed a some SG350-28's on our network, then I put together a SG350x stack but lost my notes on it. The MSP isn't willing to help me connect another SG350 and I'm having issues setting up my new IDF.

First, I cannot get a port on my SG350X stack to come back online so it will connect to my new switch.

We have these linked up with these setting when I do a show running-config (and yes, it's the same as startup-config)

!
interface GigabitEthernet27
description "Uplink to Core"
switchport mode trunk
no macro auto smartport
!
!
interface GigabitEthernet27
description "Uplink To Warehouse"
switchport mode trunk
switchport trunk allowed vlan remove 100
no macro auto smartport
!

!
interface GigabitEthernet12
description "Uplink to Cisco LAN Stack"
switchport mode trunk
!
!
interface GigabitEthernet1/0/48
description "Uplink to Core"
switchport mode trunk
no macro auto smartport
!

So I thought I set up 3/0/1 right, but I believe STP disabled the port. Now I have the ports set like this.

!
interface GigabitEthernet3/0/1
switchport mode trunk
no macro auto smartport
!
!
interface GigabitEthernet50
switchport mode trunk
no macro auto smartport
!

but I can't get 3/0/1 to come back up. It looks like it should be back up but when I pull up the STP settings in the web interface, you can see it's still set as disabled. 

I know I have to be overlooking something simple and obvious, any help is greatly appreciated.

[balaji.bandi]

Are you looking to add new switch in to exiting stack ?(what is the exiting arrangement running, stack? how many switches ?)

here is stacking config :

https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-350x-series-stackable-managed-switches/smb5408-configure-stack-settings-on-an-sg350x-switch.html

[DigitalManiak3k]

Sorry no, I'm just connecting another switch to my stack, not adding to the stack. I would have normally connected it to the core switch, and it will be later but there's no direct line to it and I didn't feel like running a cable through the wall and ceiling just to set this up. I'm using one of my spare connectors in my office that's patched into 3/0/1 in the SG350X stack.

[balaji.bandi]

what is the mode of connectivity is this Eterhent or Fibre ?  you are extending Layer 2 to another new switch.

this how you do both sides.

https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-350-series-managed-switches/smb5827-configure-vlan-interface-settings-on-a-sx350-sg350x-or-sx550.html

[DigitalManiak3k]

Ethernet for testing, fiber when I put it in production. That link did not show me where I can re-enable that port.

[DigitalManiak3k]

So I sacrificed another port on my stack to re-create what I did. Now 1/0/29 is dead like 3/0/1. Understand I can't get either port to link to anything right now. I patched the switch into 1/0/29 while logged into the web interface.

I so when I look at the port settings, it's showing "Operational Status: Down (BPDU Guard)" just like 3/0/1 did.

So now the two ports are in essentially the same status, a problem I need to fix.

[Martin Aleksandrov]

Hi there,

How many links do you have connected to the new switch you are trying to add? You might be in a case where STP triggers the port and forces it to shut down. If BPDU guard is enabled on that port (s) at the reception of BPDUs, the BPDU guard operation disables the port that has BPDU configured. In this case, a BPDU message is received and an appropriate SNMP trap is generated. Check and see if BPDU guard is enabled on these ports (https://www.cisco.com/c/en/us/support/docs/smb/switches/cisco-350x-series-stackable-managed-switches/smb5102-configuring-stp-interface-settings-on-the-sg350xg-and-sg550x.html) This is in STP interface settings.

Regards,

Martin

[DigitalManiak3k]

That's exactly what happened, which is why I'm trying to fix the down port. When I disable BPDU prior to connecting, it works fine. That switch had zero connections on it, I was trying to connect it so I could finish the setup and begin testing on it prior to deployment.

Need to get those ports operational again without having to reboot my stack. Any suggestions?

[cyberconsultants]

From 'Advanced' GUI... Port Management > Error Recovery Settings ...and then manually release the suspended port/s if so listed.

You can also configure automatic recovery settings from this pane, including for BPDU guard suspensions.