Re: DTP - Interpreting the Question

I personally think that i should have "switchport mode dynamic desirable" on
SW2 because the question says "SW2 should negotiate 802.1q as trunking
protocol to SW1". But definitely i would go to proctor and ask whether SW2
should initiate DTP negotiation.

Sud.

On Thu, May 19, 2011 at 6:31 PM, Nathan Falcon <nathan.falcon_at_gmail.com>wrote:

> Pretty tricky....I'm not so sure I agree here. It seems to me that a
> solution that would fail after a reboot or interface reset would be
> incorrect.
>
> Disabling DTP on SW1 would not kill the already negotiated trunk, but if
> you shut/no shut the SW2 side it won't come back up. I'm not so sure this
> question is really looking for DTP to be disabled. It would be necessary
> for proper functionality. This is how i'm perceiving the solution for this
> one.
>
> (This might be a good one to go to the proctor on too....I bet you could
> get the answer out of him/her if you choose your words right.)
>
> SW1
> interface FastEthernet0/24
> switchport trunk encapsulation dot1q
> switchport mode trunk
>
> SW1#sh int trunk
>
> Port Mode Encapsulation Status Native vlan
> Fa0/24 on 802.1q trunking 1
>
>
>
> SW2
> interface FastEthernet0/24
> (dynamic desirable would work here to, but seems unnecessary)
>
> SW2#sh int trunk
> Port Mode Encapsulation Status Native vlan
> Fa0/24 auto n-802.1q trunking 1
>
> Nate
>
>
>
> On Thu, May 19, 2011 at 8:31 AM, Edwin Campbell <
> edwin.l.campbell_at_gmail.com> wrote:
>
>> I agree with Leonardo 100%. If you were going to connect two switches via
>> a
>> trunk link and before you cabled it up, you added the "switchport
>> nonegotiate" command, yes, that would stop the trunking protocol
>> negotiation.
>>
>> The only way that the switchport nonegotiate command would not stop a
>> trunk
>> link from negotiating would be if you added that command after your trunks
>> have already gone through the negotiation process. Because the switches
>> have already negotiated which trunking protocol that they're going to use,
>> adding the "switchport nonegotiate" will not effect anything.
>>
>> Lab it up =).
>>
>> Edwin
>>
>>
>>
>> On Thu, May 19, 2011 at 4:19 PM, Leonardo Hideki
>> <leohideki.ccie_at_gmail.com>wrote:
>>
>> > Hi Roy,
>> >
>> > I thought of that also, but disabling DTP wouldn't prevent SW2 from
>> > learning
>> > which encap type it should use as well?
>> >
>> > Rgrds,
>> >
>> > Leonardo Hideki
>> >
>> >
>> >
>> > On Thu, May 19, 2011 at 8:36 AM, Roy Khan <roykhan123_at_hotmail.com>
>> wrote:
>> >
>> > >
>> > > Hi Guys
>> > >
>> > > Perfect solution Just I add one more command
>> > >
>> > > int fax/x
>> > > > switchport trunk encap dot1q
>> > > > switchport mode trunk
>> > > *Switchport Nonegotiate *
>> > > when you type show int trunk command on this switch you will see Mode
>> is
>> > > -On- it and Encapsulation means
>> > > you statically configure the trunk.
>> > > also use *show int Fax/x switchport* command to verify this.
>> > > Remember 3560 default mode is switchport dynamic auto.
>> > >
>> > > Br
>> > >
>> > > Roy
>> > >
>> > >
>> > > > Date: Thu, 19 May 2011 06:24:37 -0300
>> > > > Subject: Re: DTP - Interpreting the Question
>> > > > From: leohideki.ccie_at_gmail.come
>> > > > To: mitsuie2_at_gmail.com
>> > > > CC: ccielab_at_groupstudy.com
>> > >
>> > > >
>> > > > Hi Sud,
>> > > >
>> > > > As SW1 should not negotiate, you should configure dot1q / trunk
>> > > statically:
>> > > >
>> > > > !
>> > > > int fax/x
>> > > > switchport trunk encap dot1q
>> > > > switchport mode trunk
>> > > > !
>> > > >
>> > > > On SW2, it could be either desirable or auto, since SW1 is
>> statically
>> > > > configured to trunk.
>> > > >
>> > > > !
>> > > > int fax/x
>> > > > switchport mode dynamic [auto | desirable]
>> > > > !
>> > > >
>> > > > In order to check this config, issue a "sh int trunk" on both sides.
>> On
>> > > > switch 1, it should come up with "802.1q" while on switch 2, it
>> should
>> > > come
>> > > > up with "n-802.1q", "n" meaning that the trunking protocol was
>> > > negotiated.
>> > > >
>> > > > HTH.
>> > > >
>> > > > Rgrds,
>> > > >
>> > > > Leonardo Hideki
>> > > >
>> > > > On Mon, May 16, 2011 at 4:28 AM, Sud Mu <mitsuie2_at_gmail.com> wrote:
>> > > >
>> > > > > Hi All,
>> > > > >
>> > > > > I've got a problem in interpreting this DTP question
>> > > > >
>> > > > > If there was a question where SW1 and SW2 are directly connected.
>> > > > >
>> > > > > Question:
>> > > > > =======
>> > > > > Link between SW1 and SW2 should be a 802.1q trunk. SW1's port
>> should
>> > be
>> > > > > configured statically to have 802.1q trunking. SW2 should
>> negotiate
>> > > 802.1q
>> > > > > as trunking protocol to SW1. SW1 should not negotiate 802.1q to
>> SW2.
>> > > > >
>> > > > > Where should I put "switchport mode dynamic desirable" ? on SW1 or
>> > SW2
>> > > ?
>> > > > >
>> > > > > Although simple please give you experts idea
>> > > > >
>> > > > > Thanks,
>> > > > > Sud
>> > > > >
>> > > > >
>> > > > > Blogs and organic groups at http://www.ccie.net
>> > > > >
>> > > > >
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Received on Fri May 20 2011 - 15:40:38 ART