Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

vlan 1 minimization and native vlan

When I connect two switches using trunk ports, by default Vlan1 will be the native vlan for the trunk ports. The recommended practice is to assign a non default vlan vlan1 and also no to use management vlan as native vlan. Is it mandatory to define a native vlan for trunk ports?

What is vlan 1 minimization?

1 ACCEPTED SOLUTION

Accepted Solutions
New Member

vlan 1 minimization and native vlan

If you intend, per interface you doesn't need to configure the command native vlan, you only need the command switchport trunk encapsulation dot1q, switchport mode trunk, and it works, but the vlan allowed on this trunk is all from 1 to 4095, and the native is implicit vlan 1. If switch on both side are cdp enabled on trunk interface, and different natvie is specified on one of the switch you will see this error, %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered, and need to see the configuration and change tha native on one of the side.

5 REPLIES
New Member

vlan 1 minimization and native vlan

Vlan 1 is the default vlan for Cisco, vlan1 is sent over trunk links untegged so without a "badge" who say wich vlan is. If on a switch the default vlan is 1 and on the other side of link vlan2 is native both are untegged and traffic from the "pipe" vlan 1 go in 2 so if someon sent frame untagged that come in native vlan over trunk... so doesn't use native as managementVlan. Native can also be sent tagged with command vlan dot1q tag native in global config.

New Member

vlan 1 minimization and native vlan

Understood. However is it mandatory to define a native vlan for trunk ports?

New Member

vlan 1 minimization and native vlan

If you intend, per interface you doesn't need to configure the command native vlan, you only need the command switchport trunk encapsulation dot1q, switchport mode trunk, and it works, but the vlan allowed on this trunk is all from 1 to 4095, and the native is implicit vlan 1. If switch on both side are cdp enabled on trunk interface, and different natvie is specified on one of the switch you will see this error, %CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered, and need to see the configuration and change tha native on one of the side.

New Member

vlan 1 minimization and native vlan

Thank You,

Long back allowing vlan1 on trunk port was mandatory however it's not required anymore. How is it achieved and what is vlan1 minimization?

New Member

vlan 1 minimization and native vlan

On trunk link, switchport trunk allowed vlan 2,3,5,10... or 10-15 if you would insert single vlan put a , between vlan if is a range from 10 to 15 for example put the -.

1172
Views
0
Helpful
5
Replies