By default in Spanning tree all the ports will go through some list of states whenever switch boots up. This states are used to avoid switching loops.This states are not useful on the ports where end devices ( PC, Laptop, Servers) are connected. We can override this states by using Spanning Tree feature called as PORT FAST.
Without Port Fast Spanning Tree states
1) Blocking ---- 20 seconds
2) Listening ----- 15 Seconds
3) Learning------ 15 Seconds
4) Forwarding
With Port Fast directly the port will enter into Forwarding State, without going into Blocking, Listening and Learning thus by saving 50 seconds. We need to implement this feature on the ports where end devices are connected.
We can configure Port Fast in two ways
i) Global Configuration Mode
ii) Interface Mode
i) Global Configuration Mode : Command will apply on all access ports.
Switch(config)# spanning-tree portfast default
ii) Interface Mode: Command will apply on the particular interface only
Switch(config)# interface fastethernet 0/0
Switch(config-if)# spanning-tree portfast
Note: We can configure Port Fast on Trunk ports also, such as ports which are connected to hypervisors and routers.
Switch(conf)# interface fastethernet0/1
Switch(conf-if)# spanning-tree portfast trunk
To Disable Spanning-Tree Port Fast
Switch(config)# interface fastethernet 0/1
Switch(config-if)# spanning-tree portfast disable
Note: To check Port Fast Status on the interfaces, just use this command
Switch# show spanning-tree detail
Without Port Fast Spanning Tree states
1) Blocking ---- 20 seconds
2) Listening ----- 15 Seconds
3) Learning------ 15 Seconds
4) Forwarding
With Port Fast directly the port will enter into Forwarding State, without going into Blocking, Listening and Learning thus by saving 50 seconds. We need to implement this feature on the ports where end devices are connected.
We can configure Port Fast in two ways
i) Global Configuration Mode
ii) Interface Mode
i) Global Configuration Mode : Command will apply on all access ports.
Switch(config)# spanning-tree portfast default
ii) Interface Mode: Command will apply on the particular interface only
Switch(config)# interface fastethernet 0/0
Switch(config-if)# spanning-tree portfast
Note: We can configure Port Fast on Trunk ports also, such as ports which are connected to hypervisors and routers.
Switch(conf)# interface fastethernet0/1
Switch(conf-if)# spanning-tree portfast trunk
To Disable Spanning-Tree Port Fast
Switch(config)# interface fastethernet 0/1
Switch(config-if)# spanning-tree portfast disable
Note: To check Port Fast Status on the interfaces, just use this command
Switch# show spanning-tree detail
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