switchport no negoiate command

Answered Question
Jun 22nd, 2010

Hi all

Can anyone confirm if that if I plug a trunk port from one switch into an access port on another switch, will this form a trunk automatically? where should I issue the command, on trhe trunk port to stop it sending DTP frames ?


cheers


Carl

Correct Answer by francisco_1 about 6 years 8 months ago

In respoinding to your first comment,


trunking will form if the switch with the trunk is negotiating through DTP (desirable) then the other switch will respond to DTP negotiation request and form trunk.


DTP negotiation can be disabled two ways, with the switchport access mode command or with the switchport nonegetiate command. If trunking is needed, but DTP is diable, it must be statically configured with the switchport mode trunk command. This design is most commonly used when a switch is trunking to a device that does not support DTP such as IOS routers routed ethernet interface )Not an etherswitch interface), or a servers NIC card.



Francisco

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Ganesh Hariharan Tue, 06/22/2010 - 04:03

Hi all

Can anyone confirm if that if I plug a trunk port from one switch into an access port on another switch, will this form a trunk automatically? where should I issue the command, on trhe trunk port to stop it sending DTP frames ?


cheers


Carl


Carl,


The switchport no negotiate command is used to stop the port from sending DTP messages (Dynamic Trunk Port).If you want the port to stop sending DTP frames, use switchport nonegotiate command.


If you enter access mode, the interface goes into permanent nontrunking mode and If you enter trunk mode, the interface goes into permanent trunking mode


Hope to Help !!


Ganesh.H


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Chetan Kumar Ress Tue, 06/22/2010 - 04:16

Hi Carl


"Switchport nonegoiate"


Puts the LAN port into permanent trunking mode but prevents the port from generating DTP frames. You must configure the neighboring port manually as a trunk port to establish a trunk link


& If you configured the port as an access mode then it will not from Trunk between both switches.


Regards

Chetan Kumar

carl_townshend Tue, 06/22/2010 - 05:42

Hi

If I manually set the port to trunk, will it still send DTP frames if I dont use the no-negoiate command ?

andre.ortega Tue, 06/22/2010 - 06:38

Yes, without switchport nonegotiate command layer 2 interface will still send DTP.


"Use the switchport nonegotiate interface configuration command to specify that Dynamic Trunking Protocol (DTP) negotiation packets are not sent on the Layer 2 interface."


For send DTP use command no switchport nonegotiate.


Regards.

Correct Answer
francisco_1 Tue, 06/22/2010 - 07:01

In respoinding to your first comment,


trunking will form if the switch with the trunk is negotiating through DTP (desirable) then the other switch will respond to DTP negotiation request and form trunk.


DTP negotiation can be disabled two ways, with the switchport access mode command or with the switchport nonegetiate command. If trunking is needed, but DTP is diable, it must be statically configured with the switchport mode trunk command. This design is most commonly used when a switch is trunking to a device that does not support DTP such as IOS routers routed ethernet interface )Not an etherswitch interface), or a servers NIC card.



Francisco

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