---
id: 1779884291-BCDN
aliases:
  - PortFast (STP Toolkit)
tags: []
---

# PortFast (STP Toolkit)

ex:
Switch <-> PC

Listening
   | 15sec
Learning
   | 15sec
Forwarding

When an end host connects to a switch port, the port becomes up/up but can't send/receive data yet.
- It is a *Designated port* but will take 30 seconds before it enters the Forwarding state:
  - 15 seconds in Listening
  - 15 seconds in Learning
This lead to poor user experience
- the user probably doesn't even know [[STP]] exists.
- They just know "the internet doesn't work" for 30 seconds when they connect their computer.
- This wait is unnecessary, because there is no risk of a Layer 2 loop occuring between a switch/PC

## The solution

When portFast is configured on a port, the port immediately enters the Forwardin state when connected 
to another device.
It bypasses Listening/Learning and can send/receive data right away

You can configure PortFast in two ways

1. Interface config mode

```Cisco
SW1(config-if)# spanning-tree portfast
```

This enables PortFast only on the individual interface.

*Even if you configure spanning-tree porfast on a trunk port, it won't be active.*

2. Global config mode:

```Cisco
SW1(config)# spanning-tree portfast default
```

This enables PorFast on all access ports.

      Connections between switches are almost always trunk links.
      Connections to end hosts are almost always access links.

**PortFast should NOT be configured on ports connected to switches or temporary Layer 2
loops can occur.**

## showing result

```Cisco
SW1(config)# show spanning-tree interface g0/1 detail
```

## diabling portfast

```Cisco
SW1(config-if)# spanning-tree portfast disable
```

## Configurating Portfast on trunk port

In some cases, you might want to enable PortFast on a trunk port:
- A port connected to a virtualization server with virtual machines (VMs) in different VLANs.
- A port connected to a [[router]] via router on a stick [[ROAS]].

This can only be cofigured per-port in interface config mode:

```Cisco
SW1(config-if)# spanning tree portfast trunk
```

## PortFast Edge

In modern Cisco switches, if you use the commands covered in this lecture, the device will automatically
add the edge keyword to the configuration.

```Cisco
SW1(config-if)# spanning-tree portfast
running-config
spanning-tree portfast edge
```

```Cisco
SW1(config-if)# spanning tree portfast trunk
running-config
spanning-tree portfast edge trunk
```

```Cisco
SW1(config)# spanning-tree portfast default
running-config
spanning-tree portfast edge default
```

You can use either version of the commands when configuring PortFast.

The end result is the same: edge will always be added in the configuraion.

spanning-tree portfast disable doesn't use the *edge* keyword.


## two kind of Portfast

There are two kinds of PortFast:
-  edge
  - edge is the kind we are covering in this video
-  network
  - network is used for a feature called Bridge Assurance (not a CCNA topic)

## Review

### PortFast:
Allows switchs ports connected to end hosts to immediately enter the STP Forwarding state.
Bypassing Linstening and Learning