The primary VLAN

As certain features and management functions run on only one VLAN in the switch and because DHCP and Bootp can run per-VLAN, there is a need for a dedicated VLAN to manage these features and ensure that multiple instances of DHCP or Bootp on different VLANs do not result in conflicting configuration values for the switch.

The Primary VLAN is the VLAN the switch uses to run and manage these features and data. In the factory-default configuration, the switch designates the default VLAN (DEFAULT_VLAN; VID=1) as the Primary VLAN. However you can designate another static, port-based VLAN as primary.

To summarize, designating a non-default VLAN as primary means that:
  • The switch reads DHCP responses on the Primary VLAN instead of on the default VLAN. This includes such DHCP-resolved parameters as the TimeP server address, Default TTL and IP addressing—including the Gateway IP address—when the switch configuration specifies DHCP as the source for these values.

  • The default VLAN continues to operate as a standard VLAN you cannot delete it or change its VID.

  • Any ports not specifically assigned to another VLAN will remain assigned to the Default VLAN, even if it is the Primary VLAN.

Candidates for Primary VLAN include any static, port-based VLAN currently configured on the switch.

Protocol-Based VLANs and dynamic (GVRP-learned) VLANs that have not been converted to a static VLAN cannot be the Primary VLAN. To display the current Primary VLAN, use the CLI show vlan command.


If you configure a non-default VLAN as the Primary VLAN, you cannot delete that VLAN unless you first select a different VLAN to serve as primary.

If you manually configure a gateway on the switch, it ignores any gateway address received via DHCP or Bootp.