VLAN operating notes


If you are using DHCP/Bootp to acquire the switch's configuration, packet time-to-live and TimeP information, designates the VLAN on which DHCP is configured as the Primary VLAN.


In the factory-default configuration, the DEFAULT_VLAN is the Primary VLAN.

Per-VLAN features

IGMP and some other features operate on a per VLAN basis. This means you must configure such features separately for each VLAN in which you want them to operate.

Default VLAN

You can rename the default VLAN, but you cannot change its VID (1) or delete it from the switch.

VLAN port assignments

Any ports not specifically removed from the default VLAN remain in the DEFAULT_VLAN, regardless of other port assignments. Also, a port must always be a tagged or untagged member of at least one port-based VLAN.

Voice-Over-IP (VoIP)

VoIP operates only over static, port-based VLANs.

Multiple VLAN types configured on the same port

A port can simultaneously belong to both port-based and protocol-based VLANs.

Protocol Capacity

A protocol-based VLAN can include up to four protocol types. In protocol VLANs using the IPv4 protocol, to support normal IP network operation ARP must be one of these protocol types (to support normal IP network operation). Otherwise, IP traffic on the VLAN is disabled.

If you configure an IPv4 protocol VLAN that does not include the ARP VLAN protocol, the switch displays the following message which indicates a protocol VLAN configured with IPv4 but not ARP:
switch(config)# vlan 97 protocol ipv4

IPv4 assigned without ARP, this may result in undeliverable IP packets.
Deleting Static VLANs

A VLAN can be deleted even if there are currently ports belonging to it. The ports are moved to the default VLAN.

Adding or Deleting VLANs

Changing the number of VLANs supported on the switch, requires a reboot.


From the CLI, you must perform a write memory command before rebooting. Other VLAN configuration changes are dynamic.