What is PortFast port?

What is PortFast port?

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.

What is spanning-tree PortFast edge trunk?

PortFast. PortFast immediately brings an interface configured as an access or trunk port to the forwarding state from a blocking state, bypassing the listening and learning states. An interface with PortFast enabled goes through the normal cycle of spanning-tree status changes when the switch is restarted.

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 is spanning-tree PortFast used for?

You can use PortFast on switch or trunk ports that are connected to a single workstation, switch, or server to allow those devices to connect to the network immediately, instead of waiting for the port to transition from the listening and learning states to the forwarding state.

How do I enable port fast?

In switch A, run the following commands as port 20 is connected to a host.

1. Enter the configuration mode for the interface.
2. Shut down the interface.
3. Change the portfast setting.
4. Review the portfast status.
5. Reset the default spanning tree portfast value for the interface.
6. Review the portfast status.

Do access ports send BPDUs?

all access ports or be configured directly under the interface. it will continue to use portfast and bridging loops may appear. Part of the myth is also that portfast enabled ports do not send BPDUs. BPDUs are still sent on portfast enabled ports.

Where do I turn in Bpdu guard?

Understanding BPDU Guard At the global level, you enable BPDU guard on Port Fast-enabled STP ports by using the spanning-tree portfast bpduguard default global configuration command.

What is edge port mode?

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.

Can we use spanning Portfast on trunk ports?

It is recommended to enable PortFast only on access port types. However, PortFast can be enabled on the trunk ports by selecting the Trunk check box in the WebUI.

When should I disable spanning-tree?

The most common reason for disabling spanning tree is that the original 802.1D Spanning Tree Protocol (STP) goes through a fairly lengthy wait period from the time a port becomes electrically active to when it starts to pass traffic.

When should Spanning Tree Portfast be used?

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.

Does spanning-tree Run on access ports?

Spanning tree uses the port cost value when an interface is configured as an access port and uses VLAN port cost value when an interface is configured as a trunk port. Spanning tree port cost value calculations are based on the bandwidth of the port.

How does portfast in a trunk port work?

Portfast enables a port to skip LIS, LRN states of STP and transition directly from BLK to FWD mode. This saves convergence time on this port and the device connected here (normally a host) doesnot have to go wait for 15+ sec to be up.

Can you use spanning-tree portfast trunk on another Cisco switch?

You should almost never apply a spanning-tree portfast trunk command to another cisco switch. If you go back to the basics… spanning-tree portfast allows the ports to skip the blocking to fowarding states and go immediately to forwarding. The spanning-tree portfast trunk does the same but for trunk connections.

Can you enable portfast on a stick case?

If you enable PortFast on a port that is connected to another Layer 2 device, such as a switch, you might create network loops. But you can enable portfast with router on stick case.where you have switch with trunk configured with router interface. Hope to Help !! 03-12-2010 12:45 AM 03-12-2010 12:45 AM

Which is the most secure implementation of portfast?

The most secure implementation of PortFast is to enable it only on ports that connect end stations to switches. Because PortFast can be enabled on nontrunking ports connecting two switches, spanning tree loops can occur because BPDUs are still being transmitted and received on those ports.