Re: DTP - Interpreting the Question

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 Thu May 19 2011 - 09:01:31 ART