From: Thomwin Chen (thomwin_chen@yahoo.com)
Date: Sat Oct 22 2005 - 04:29:31 GMT-3
sorry,
correction :
CATA - fa0/1<-------------------->fa0/1 - CATB
Thomwin Chen <thomwin_chen@yahoo.com> wrote:
yes, I guess it's not necessary to config it.
unless if it's asked explicitly or implicitly.
but for hardcoded trunk (switchport mode trunk), the DTP still needed in this example case.
example :
CATA - fa0/1<-------------------->fa0/2 - CATB
if you configure CATA fa0/1 like this :
int fa0/1
switchport trunk encapsulation isl
switchport mode trunk
switchport nonegotiate
and you configure CATB fa0/1 like this :
int fa0/1
switchport mode dynamic desirable
the link between CATA and CATB will never become a trunk.
(verify this with show interface trunk)
but if you remove the switchport nonegotiate syntax on CATA, the trunk will succeed.
The Great Ryan
wrote:
Yes, I found that when I put an interface port into access mode (i.e.
switchport mode access), it will not negotiate to become trunk (i.e.
no DTP to send).
Is it not necessary to put "switchport nonegotiate" on access port ?
i.e.
interface FastEthernet0/25
switchport mode access
switchport nonegotiate <-- useless/no need
However, I found from Cisco Documentation that "switchport
nonegotiate" is valid when the interface switchport mode is access or
trunk.
It said that it is VALID. But In the point of my view, it is useless
when the interface switchport mod is access.
Correct me if I have mistake on that. Thanks !
Ryan
2005/10/22, CCIEBOB :
> Also using the "show dtp interface X" command.
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Thomwin Chen
> Sent: Friday, October 21, 2005 11:22 AM
> To: The Great Ryan; Cisco certification
> Subject: Re: "switchport nonegotiate" & DTP traffic
>
> Hi Ryan,
>
> you can verify this using switchport int fa0/x switchport
>
> you should see something like this :
>
> Negotiation of trunking : On or Off
>
> Example :
>
>
>
> 3550#show int fa0/5 swi
> Name: Fa0/5
> ....
> Negotiation of Trunking: On
> Access Mode VLAN: 1 (default)
> ....
> 3550#conf t
> Enter configuration commands, one per line. End with CNTL/Z.
>
>
>
> 3550(config)#int fa0/5
> 3550(config-if)#swi
> 3550(config-if)#switchport mode acc
> 3550(config-if)#do show int fa0/5 swi
> Name: Fa0/5
> ....
> Negotiation of Trunking: Off
> Access Mode VLAN: 1 (default)
> ....
>
> 3550(config-if)#
>
> Rgds,
> Thomwin
>
> The Great Ryan
wrote:
> Hi, Group,
>
> it is not difficult to understand that "switchport nonegotiate" is
> used to disable DTP traffic when the interface port is in trunk mode.
> However, I found from Cisco Documentation that "switchport
> nonegotiate" is valid when the interface switchport mode is access or
> trunk.
>
> As DTP is used to negotiate interfaces to become trunk, what is the
> use of "switchport nonegotiate" when I already hardcode the interface
> to become access port. Is DTP still being sent even when the interface
> port is in access port?
>
> i.e.
> Rack2R7#s run int f0/25
> Building configuration...
>
> Current configuration : 82 bytes
> !
> interface FastEthernet0/25
> switchport mode access
> switchport nonegotiate
> end
>
>
>
> Ryan
>
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