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Spanning Tree Features Placement

Hi all , 

During my googling i founded this topology below for Spanning Tree Features Placement, I just wonder why the Loopguard used only on these specific ports on the topology why not used on all ports , the same thing for RootGuard and so on ,,,    

STP.png

Kind Regards, 

Tariq.E

6 Replies 6

marce1000
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 -  In standard networking spanning tree convergence will be sufficient to have an operational network ; do no go into loop-guard or root-guard unless there are well defined requirements.

 M.



-- Each morning when I wake up and look into the mirror I always say ' Why am I so brilliant ? '
    When the mirror will then always repond to me with ' The only thing that exceeds your brilliance is your beauty! '

Thanks for your replay ... Yes, but i was mean in this topology these features applied on specific ports not all ports !!  Is this mean any feature such as LoopGurad should applied on specific ports on topology or can applied on any port ?  Is there rule where to apply these features on ports ?

 

Loopguard should be applied on inter-switch connections where you expect to receive a BPDU. It is the absence of a BPDU being received that should be of concern to the switch so it places it in a loop-inconsistent blocking state.

 

cheers,

Seb.

Thanks .. As i know the LoopGuard working with unidirectional link failure .. So any change in the topology will change the loop-inconsistent blocking state .. This mean i have to expect to receive the BPDU from any port in the topology ..

Kindly is there any update ?

 

Kind Regards

You should expect to receive a BPDUs on ports connected to any switch. You will want to use BPDU-Guard on switchports not connected to your own switches to ensure rogue switches cannot effect the STP topology and potentially become the root bridge.

For the ports connecting your own switches together configure Loop Guard. On these ports you expect to (and want to ) receive BPDUs, if you don't place the port in an inconsistent state to prevent switching loops from forming.

 

cheers,

Seb.

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