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webabc123
Beginner

When can PortFast be used?

The support site says:

"If you connect a workstation or a server with a single NIC card or an IP phone to a switch port, the connection cannot create a physical loop. These connections are considered leaf nodes. There is no reason to make the workstation wait 30 seconds while the switch checks for loops if the workstation cannot cause a loop. Cisco added the PortFast or fast-start feature. With this feature, the STP for this port assumes that the port is not part of a loop and immediately moves to the forwarding state and does not go through the blocking, listening, or learning states. This command does not turn STP off. This command makes STP skip a few initial steps (unnecessary steps, in this circumstance) on the selected port."

So what if user's desks have single ports with the IP phone plugged directly into the Ethernet jack so it gets POE and then the desktop PC plugged into "PC" port in the the phone?  So the IP phone is working as a switch so both the IP phone and the PC can share a single port.

What about single NIC PCs plugged into a desktop switch (Netgear-type4-8 port consumer) so more PCs can be connected in a cubical than there are wall jacks available?

We are having connection delays on reboot of workstations and we would like to find out how to optimize our PC connection setup so we can get Portfast enabled everywhere workstations are connected.

2 ACCEPTED SOLUTIONS

Accepted Solutions
Philip D'Ath
Advisor

You can use portfast anytime you are confident what is being plugged in can not cause a loop.

A workstation can't create a loop.  A phone shouldn't create a loop.

You could make your Netgear a portfast port if you like.  It can create a loop.  So be careful that it never gets dual connected to switch.

View solution in original post

I mean more than one connection between your Cisco switch using portfast, and the NetGear switch.

View solution in original post

3 REPLIES 3
Philip D'Ath
Advisor

You can use portfast anytime you are confident what is being plugged in can not cause a loop.

A workstation can't create a loop.  A phone shouldn't create a loop.

You could make your Netgear a portfast port if you like.  It can create a loop.  So be careful that it never gets dual connected to switch.

View solution in original post

What do you mean dual connected?  Do you mean the desktop switch connected to more than one network port?

I mean more than one connection between your Cisco switch using portfast, and the NetGear switch.

View solution in original post