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Orbi WiFi 7 RBE973
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Re: IGMP TCN Flood

kaboomcanuck2
Initiate

IGMP TCN Flood

Hi,

 

How do these switches handle topology changes with STP? Do they flood traffic for a period of time like other switches. If so do they have a command similar to that of ciscos "no igmp snooping tcn flood"

 

Can't find any information on this so any insight would be appreciated. We've recently had a broadcast storm and are reviewing our topology.

 

Thank you,

 

Message 1 of 4

Accepted Solutions
LaurentMa
NETGEAR Expert

Re: IGMP TCN Flood

Hi @kaboomcanuck2 ,

 

TCN get flooded by default. I would recommend you manipulate the Bridge Priority at the very least at your core, with a lower value (for instance, 0) in order to get elected as the root - when all other M4250 switches keep their 32K default value. We allow for it in the AV user interface, welcome page, with the Main/Backup STP entry. 

 

To answer your question, please find the M4250 CLI admin manual here: https://www.netgear.com/support/product/m4250#docs

 

You can use the spanning-tree tcnguard command at the interface level to restrict topology change notification propagation:

>Enable

#Config

#interface 0/1-0/48

#spanning-tree tcnguard

#exit

#exit

#save

 

spanning-tree tcnguard

Use this command to enable TCN guard on the interface. When enabled, TCN Guard restricts the interface from propagating any topology change information received through that interface.

 

Default

Enabled

Mode

Interface Config


spanning-tree tcnguard

 

 

no spanning-tree tcnguard

This command resets the TCN guard status of the port to the default value.

 

Mode

Interface Config

   

no spanning-tree tcnguard

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Message 2 of 4

All Replies
LaurentMa
NETGEAR Expert

Re: IGMP TCN Flood

Hi @kaboomcanuck2 ,

 

TCN get flooded by default. I would recommend you manipulate the Bridge Priority at the very least at your core, with a lower value (for instance, 0) in order to get elected as the root - when all other M4250 switches keep their 32K default value. We allow for it in the AV user interface, welcome page, with the Main/Backup STP entry. 

 

To answer your question, please find the M4250 CLI admin manual here: https://www.netgear.com/support/product/m4250#docs

 

You can use the spanning-tree tcnguard command at the interface level to restrict topology change notification propagation:

>Enable

#Config

#interface 0/1-0/48

#spanning-tree tcnguard

#exit

#exit

#save

 

spanning-tree tcnguard

Use this command to enable TCN guard on the interface. When enabled, TCN Guard restricts the interface from propagating any topology change information received through that interface.

 

Default

Enabled

Mode

Interface Config


spanning-tree tcnguard

 

 

no spanning-tree tcnguard

This command resets the TCN guard status of the port to the default value.

 

Mode

Interface Config

   

no spanning-tree tcnguard

Message 2 of 4
kaboomcanuck2
Initiate

Re: IGMP TCN Flood

Thank you - we will do this for all our edge ports. We do have our main switch \ IGMP querier set as the root bridge. 


Just want to add that you do a great job Laurent!

 

 

Message 3 of 4
LaurentMa
NETGEAR Expert

Re: IGMP TCN Flood

Thank you, @kaboomcanuck2      🙂

Message 4 of 4
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