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Not able to change auto to trunk mode on switch

aksher
Level 1
Level 1

SW-B-TOP(config-if)#switchport mode trunk

When trying to execute the above command am getting the following error.

Command rejected: An interface whose trunk encapsulation is "Auto" can not be configured to "trunk" mode.

29 Replies 29

glen.grant
VIP Alumni
VIP Alumni

You have to specifically set the encapsulation type first "switchport encapsulation dot1q" then try youir command...

it's not accepting.

SW-B-TOP(config-if)#switchport encapsulation dot1q

^

% Invalid input detected at '^' marker

the model is CGESM.

You forgot the "TRUNK" portion to the command. It's SWITCHPORT TRUNK ENCAPSULATION DOT1Q

it was quick thanks for this handy command

Thanks a lot.It worked for me

Thanks for that. Sometimes I'm a dummy lol.

glen.grant
VIP Alumni
VIP Alumni

You need to specifically set the encapsulation first , "switchport encapsulation dot1q" then issue your trunk command...

Thanks :)

specially in cisco 3500 series..

 

Switch (config-if) # switchport trunk encapsulation ( dot1q | isl )

If you are using cisco use command

#switchport trunk encapsulation isl

#switchport mode trunk

 

OR ( multi-vendors like hp, juniper & also for cisco)

 

#switchport trunk encapsulation dot1q

#switchport mode trunk

                     

 

 

I hope It helps you


@glen.grant wrote:

You need to specifically set the encapsulation first , "switchport encapsulation dot1q" then issue your trunk command...



specially in cisco 3500 series..

 

Switch (config-if) # switchport trunk encapsulation ( dot1q | isl )

If you are using cisco use command

#switchport trunk encapsulation isl

#switchport mode trunk

 

OR ( multi-vendors like hp, juniper & also for cisco)

 

#switchport trunk encapsulation dot1q

#switchport mode trunk

                     

 

Thank you kindly, you helped in finding a solution to my problem.  :)

glen.grant
VIP Alumni
VIP Alumni

can you post the config...

Hi All,

The command which he need to enter first is

"switchport trunk encapsulation dot1q " and then he can confgigure the interface in trunk mode.

So try this command

switch(config)#interface fa0/1

switch(config-if)#switchport trunk encapsulation dot1q

switch(config-if)#switchport mode trunk

and you will be good to go.

HTH, if yes please rate the post.

Ankur

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