When you enable PortFast on the switch, spanning tree places ports in the forwarding state immediately, instead of going through the listening, learning, and forwarding states. By default, spanning tree sends BPDUs from all ports regardless of whether PortFast is enabled.
What is the PortFast command?
Enabling the PortFast feature causes a switch or a trunk port to enter the STP forwarding-state immediately or upon a linkup event, thus bypassing the listening and learning states. The PortFast feature is enabled at a port level, and this port can either be a physical or a logical port.
Where can I use spanning-tree PortFast?
PortFast feature should be used only to connect a single workstation to a switch port to avoid layer 2 switching loop. Spanning Tree PortFast feature causes a port to enter the forwarding state immediately, bypassing the listening and learning states.
How do I set PortFast on spanning-tree?
Configure the Spanning-Tree portfast Setting
- Enter the configuration mode for the interface. …
- Shut down the interface. …
- Change the portfast setting. …
- Review the portfast status. …
- Reset the default spanning tree portfast value for the interface. …
- Review the portfast status.
Configure the Spanning-Tree portfast Setting
- Enter the configuration mode for the interface. …
- Shut down the interface. …
- Change the portfast setting. …
- Review the portfast status. …
- Reset the default spanning tree portfast value for the interface. …
- Review the portfast status.
How do I check my spanning-tree PortFast?
To view the configured Spanning Tree PortFast enabled ports, run the "show running-config" IOS command as shown below. We can see that PortFast is enabled on access ports fa0/1 to fa0/24. To display a detailed summary of interface information, run "show spanning-tree detail" command as shown below.
How do you test for STP?
Checking the Status of Spanning-Tree Instance Interfaces
- To check the status of spanning-tree instance interface, use the show interfaces command: user@host> show interfaces interface-name.
- You can determine the status of the interface as follows: If the BPDU Error field is none, the interface is enabled.
Checking the Status of Spanning-Tree Instance Interfaces
- To check the status of spanning-tree instance interface, use the show interfaces command: user@host> show interfaces interface-name.
- You can determine the status of the interface as follows: If the BPDU Error field is none, the interface is enabled.
How do I set up a spanning tree?
Step 1 – enabling STP
switch>enable – It is used to enter privileged mode. switch#configure terminal – It is used to enter the switch management interface. switch(config)#spanning-tree vlan vlan-id – We use this command to enable the spanning tree protocol on our VLAN.
What is BPDU filter Cisco?
The STP BPDU filter feature allows control of spanning tree participation on a per-port basis. It can be used to exclude specific ports from becoming part of spanning tree operations. A port with the BPDU filter enabled will ignore incoming BPDU packets and stay locked in the spanning tree forwarding state.
How do I enable BPDU guard on port?
At the interface level, you can enable BPDU filtering on any STP port by using the spanning-tree bpdufilter enable interface configuration command without also enabling the Port Fast feature. This command prevents the interface from sending or receiving BPDUs.
How can I make port faster?
In switch A, run the following commands as port 20 is connected to a host.
- Enter the configuration mode for the interface. …
- Shut down the interface. …
- Change the portfast setting. …
- Review the portfast status. …
- Reset the default spanning tree portfast value for the interface. …
- Review the portfast status.
In switch A, run the following commands as port 20 is connected to a host.
- Enter the configuration mode for the interface. …
- Shut down the interface. …
- Change the portfast setting. …
- Review the portfast status. …
- Reset the default spanning tree portfast value for the interface. …
- Review the portfast status.
How can you tell which switch is the root bridge?
In order to identify which MS switch is the Root Bridge, navigate to Switch > Monitor > Switches and select the desired switch. In the switch status area, take note of the field called RSTP Root as it will identify which switch is the Root Bridge.
What is Portfast in Cisco switch?
PortFast causes a switch or trunk port to enter the spanning tree forwarding state immediately, bypassing the listening and learning states.
What is Portfast used for?
The PortFast feature is introduced to avoid network connectivity issues. These issues are caused by delays in STP enabled ports moving from blocking-state to forwarding-state after transitioning from the listening and learning states.
How do I disable Portfast on a Cisco switch?
Note You can use the spanning-tree portfast default global configuration command to globally enable the Port Fast feature on all nontrunking STP ports. To disable the Port Fast feature, use the spanning-tree portfast disable interface configuration command.
How do I disable spanning tree on a Cisco switch?
The spanning tree feature cannot be turned off in switches on a per port basis. Although it is not recommended, you can turn off Spanning Tree Protocol (STP) on a per-VLAN basis, or globally on the switch. Use the no spanning-tree vlan vlan-id command in order to disable STP on a per virtual LAN (VLAN) basis.
How do I test a spanning tree?
Checking the Status of Spanning-Tree Instance Interfaces
- To check the status of spanning-tree instance interface, use the show interfaces command: user@host> show interfaces interface-name.
- You can determine the status of the interface as follows: If the BPDU Error field is none, the interface is enabled.
Checking the Status of Spanning-Tree Instance Interfaces
- To check the status of spanning-tree instance interface, use the show interfaces command: user@host> show interfaces interface-name.
- You can determine the status of the interface as follows: If the BPDU Error field is none, the interface is enabled.
What is a characteristic of the PortFast feature?
Enabling the PortFast feature causes a switch or a trunk port to enter the STP forwarding-state immediately or upon a linkup event, thus bypassing the listening and learning states. The PortFast feature is enabled at a port level, and this port can either be a physical or a logical port.
How do you make spanning tree roots?
Method 1
- To ensure that a switch has the lowest bridge priority value, use the spanning-tree vlan vlan-id root primary command in global configuration mode. …
- If an alternate root bridge is desired, use the spanning-tree vlan vlan-id root secondary global configuration mode command.
Method 1
- To ensure that a switch has the lowest bridge priority value, use the spanning-tree vlan vlan-id root primary command in global configuration mode. …
- If an alternate root bridge is desired, use the spanning-tree vlan vlan-id root secondary global configuration mode command.
How are spanning tree roots set up?
To configure a Switch to become the Spanning Tree Protocol (STP) Root Bridge (Root Switch) for a VLAN, you can use the “spanning-tree vlan <vlan-id> root” command from the Global Configuration Mode.
How do you make a switch spanning tree root?
To configure a Switch to become the Spanning Tree Protocol (STP) Root Bridge (Root Switch) for a VLAN, you can use the “spanning-tree vlan <vlan-id> root” command from the Global Configuration Mode.
How do you test a spanning tree?
Checking the Status of Spanning-Tree Instance Interfaces
- To check the status of spanning-tree instance interface, use the show interfaces command: user@host> show interfaces interface-name.
- You can determine the status of the interface as follows: If the BPDU Error field is none, the interface is enabled.
Checking the Status of Spanning-Tree Instance Interfaces
- To check the status of spanning-tree instance interface, use the show interfaces command: user@host> show interfaces interface-name.
- You can determine the status of the interface as follows: If the BPDU Error field is none, the interface is enabled.