Networking - Spanning Tree Protocol - Discussion

Discussion :: Spanning Tree Protocol - Spanning Tree Protocol (Q.No.5)


If you want to disable STP on a port connected to a server, which command would you use?

[A]. disable spanning-tree
[B]. spanning-tree off
[C]. spanning-tree security
[D]. spanning-tree portfast

Answer: Option D


If you have a server or other devices connected into your switch that you're totally sure won't create a switching loop if STP is disabled, you can use something called portfast on these ports. Using it means the port won't spend the usual 50 seconds to come up while STP is converging.

Mohan Ayare said: (Feb 26, 2015)  
Forwarding time is 15+15 = 30 second not 50 second.

Vidya Yadav said: (Apr 23, 2015)  
Why it will take 30 sec?

Blocking---20 sec------>listening------15 sec--->learning----15 sec--->forwarding I think blocking to forwarding time will 50 sec.

Tiffany said: (Aug 30, 2015)  
I thought port fast was to reduce the time needed to reduce STP convergence, not disable it.

Joshi said: (Jun 8, 2016)  

You are right, enabling port fast doesn't mean to disable STP.

Nidhin said: (Oct 25, 2020)  
In Port fast enabled interface actually doing bypass the state which is listening and learning time for fast convergence (30 sec) it doesn't mean stp is disabled in that interfaces.

Walter said: (Jun 30, 2022)  
Bypassing listening and learning state means you are ignoring STP in a switched network. Am I right?

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