Depending on the range of the VLAN, you can configure the following parameters for VLANs (except the
default VLAN):
•
VLAN name
•
Shutdown or not shutdown
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.
About the VLAN Trunking Protocol
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 are connected with trunk interfaces. Each switch can be in only one VTP domain.
Layer 2 trunk interfaces, Layer 2 port channels, and virtual port channels (vPCs) support VTP functionality.
You can configure VTP in client or server mode. In previous releases, VTP worked only in transparent mode.
The following are the different VTP modes:
•
Server mode
—
Allows users to perform configurations, manage the VLAN database version, and store
the VLAN database.
•
Client mode
—
Does not allow users to perform configurations and relies on other switches in the domain
to provide configuration information.
•
Off mode
—
Allows users to access the VLAN database (VTP is enabled) but does not participate in
VTP.
•
Transparent mode
—
Does not participate in VTP, uses local configuration, and relays VTP packets to
other forward ports. VLAN changes affect only the local switch. A VTP transparent network switch
does not advertise its VLAN configuration and does not synchronize its VLAN configuration based on
received advertisements.
Guidelines and Limitations for VTP
VTP has the following configuration guidelines and limitations:
•
When a switch is configured as a VTP client, you cannot create VLANs on the switch in the range of 1
to 1005.
•
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.
•
If
system vlan long-name
knob is enabled, then VTP configurations will come up in OFF mode and
users can change the mode to Transparent. However, changing the mode to Server or Client is not
allowed.
•
The
show running-configuration
command does not show VLAN or VTP configuration information
for VLANs 1 to 1000.
•
Private VLANs (PVLANs) are supported only when the switch is in transparent mode.
Cisco Nexus 6000 Series NX-OS Layer 2 Switching Configuration Guide, Release 7.x
10
Configuring VLANs
About the VLAN Trunking Protocol