What is spanning-tree Portfast edge?
#spanning-tree normal. portfast edge is used to configure a port on which an end device is connected, such as a PC. All ports directly connected to end devices cannot create bridging loops in the network. Therefore, the edge port directly transitions to the forwarding state, and skips the listening and learning stages.
How do I show 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 I enable spanning-tree Portfast on a Cisco switch?
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.
What does spanning-tree Portfast do?
Portfast feature causes a switch port to enter the spanning tree forwarding state immediately, bypassing the listening and learning states.
What is an edge port?
A port is considered as an edge port when it is directly connected to the user terminal or server, instead of any other switches or shared network segments. The edge port will not cause a loop upon network topology changes. If someone maliciously attacks the switch with fake configuration BPDU, the network will flap.
What is spanning-tree Portfast default?
The spanning-tree portfast default global configuration mode command enables PortFast on all non-trunking interfaces. To configure BPDU guard on a Layer 2 access port, use the spanning-tree bpduguard enable interface configuration mode command, as shown in Example 3-6.
What is 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. When PortFast feature is enabled on a switch or a trunk port, the port immediately transitions to the STP forwarding state.
Which commands can be used to enable Portfast on a switch?
BPDU guard can be enabled on all PortFast-enabled ports by using the spanning-tree portfast bpduguard default global configuration command. Alternatively, BPDU guard can be enabled on a PortFast-enabled port through the use of the spanning-tree bpduguard enable interface configuration command.
What is PortFast command?
Does PortFast disable spanning tree?
A common misunderstanding among Cisco students is that portfast disables spanning-tree on a certain interface. This is not correct however…if you enable portfast on an interface then it will jump to the forwarding state of spanning-tree. We still run spanning-tree on the interface!
What does enabling Portfast on a Switchport do?
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 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 STP edge ports/portfast?
PortFast is usually configured on an edge port, which means the port should not receive any STP BPDUs. If the port receives any STP BPDU, it moves back to normal/regular mode and will participate in the listening and learning states. In most deployments, edge ports are access ports.
How to enable BPDU guard?
configure terminal. Enter global configuration mode.
Edge Ports. The edge port concept is already well known to Cisco spanning tree users, as it basically corresponds to the PortFast feature. All ports directly connected to end stations cannot create bridging loops in the network. Therefore, the edge port directly transitions to the forwarding state, and skips the listening and learning stages.
