Cisco Systems N3KC3048TP1GE, N3KC3064TFAL3 Configuring a Vlan, About the Vlan Trunking Protocol

Configuring VLANs

About the VLAN Trunking Protocol

When you delete a specified VLAN, the ports associated to that VLAN are shut down and no traffic flows. However, the system retains all the VLAN-to-port mapping for that VLAN, and when you reenable, or recreate, the specified VLAN, the system automatically reinstates all the original ports to that VLAN.

Note Commands entered in the VLAN configuration submode are immediately executed.

VLANs 3968 to 4047 and 4094 are reserved for internal use; these VLANs cannot be changed or used.

About the VLAN Trunking Protocol

VTP is a distributed VLAN database management protocol that synchronizes the VTP VLAN database across domains. A VTP domain includes one or more network switches that share the same VTP domain name and that are connected with trunk interfaces. Each device can be in one VTP domain, Layer 2 trunk interfaces, and Layer 2 port channels.

Guidelines and Limitations for VTP

VTP has the following configuration guidelines and limitations:

•VLAN 1 is required on all trunk ports used for switch interconnects if VTP is supported in the network. Disabling VLAN 1 from any of these ports prevents VTP from functioning properly.

•If you enable VTP, you must configure either version 1 or version 2.

•The show running-configurationcommand does not show VLAN or VTP configuration information for VLANs 1 to 1000.

•VTP pruning is not supported.

•If you are using VTP in a Token Ring environment, you must use version 2.

•You must enter the copy running-configstartup-configcommand followed by a reload after changing a reserved VLAN range. For example:

switch(config)# system vlan 2000 reserve

This will delete all configs on vlans 2000-2127. Continue anyway? (y/n) [no] y

After the switch reload, VLANs 2000 to 2127 are reserved for internal use, which requires that you enter the copy running-configstartup-configcommand before the switch reload. Creating VLANs within this range is not allowed.

•SNMP can perform GET and SET operations on the CISCO-VTP-MIB objects.

Configuring a VLAN

Creating and Deleting a VLAN

You can create or delete all VLANs except the default VLAN and those VLANs that are internally allocated for use by the switch. Once a VLAN is created, it is automatically in the active state.

	Cisco Nexus 3000 NX-OS Layer 2 Switching Configuration Guide, Release 5.0(3)U3(1)
30	OL-26590-01