Regarding Switchport Trunking....

[jegan1234]

Hi

Lets consider a layer 2 switch. Just see below configuration for an example...

!

vlan 3

name williams

!

vlan 4

name sam

!

vlan 12

name harris

!

vlan 107

name brucewilllis

!

vlan 150

name harrisonford

!

vlan 151

name willsmith

!

spanning-tree mst configuration

name config1

revision 1

instance 1 vlan 1-100

instance 2 vlan 101-200

!

!

interface GigabitEthernet1/1

switchport trunk native vlan 12

switchport trunk allowed vlan 3-20,100-200

switchport mode trunk

!

Note:

While making trunking in the interface please notice the vlan ranges 3-20,100-200.

Created vlans are only 3,4,12,107,150,151.

Question:

*The vlan ranges (3-20,100-200) mentioned in trunked interface cover non-created vlan ranges.

My question is mentioning in trunk interface with vlan ranges 3-20,100-200 numerically which are not created globally will cause any traffic related issues ????? , such as broadcast or others if any  ?????, if it causes any issues,what will be the cause if it doesnt cause any issue - why it is so....

Anyone kindly clarify me on this

Thanks

Jegan

[srereddy]

Hey Jegan,

there shouldnt be any issues in your case. Switchport trunk command wont check if the vlan is created or not created.

However, if you make any changes, the best practice always is to use 'switchport trunk allowed vlan add' for a less disruption. In your case, If you already have that command on the trunk and even if you dont have some vlans created, its not a problem.

[jegan1234]

Thank you Srereddy