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Cisco Portfast command

In cisco switches there is the Portfast feature, that blocks STP on a certain port so that the computer connects to the network faster.

I wonder if this feature is mandatory and has to be used on all switches where computers are connect to?
In cisco doc, it says it is used when a single host is connected to the port, which means if it's an access switch,and all ports have to be configured with fastport, since all ports will have computers connected to.

what about the Trunk ports do they have to have the portfast configured?

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jskfan

8/22/2022 - Mon
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governor_arnold

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jskfan

what about on the access switch ports, where all computers are connected to?
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jskfan

what I want understand is in real world environment, all computers are connected to switches.

So, are all those switches  have Portfast enabled on their ports?


in many articles, they say the computers when started first time they wait for dhcp to hand them out the IP, and when this idle time is over and the switch is still running STP, there will be a time out and the pc can't get an IP, etc...etc...

But I have not see any clear statement that says:
before you power up your computers that are connected to the switch, make sure all switch ports are in Portfast..

the only statement I see : it says portfast is enabled on a port that is connected to a single host.
it's obvious that it s a one-one connection, one port to one host.
But  should this portfast be enabled on all ports of the switch, since all ports will have computers connected to them?

Did you guys get my point?

 

 
szfeco

not mandatory just recommended.
without portfast, if your pc boots faster than the STP converge than you should wait STP to finish, after that the PC can request the IP address.

makes no point to stay 15-15secs in Listening and Learning states when only a host connected, and no loop expected



Your help has saved me hundreds of hours of internet surfing.
fblack61
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jskfan

<<not mandatory just recommended.>> it sounds vague.

Not mandatory: means there is no issue for the computers when portfast is not enabled on the switch they are connected to.

Recommended: when it's recommended ? in just some particular cases?


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jskfan

thanks