Dynamic VLANs

Dynamic VLANs
If the administrator wants to do a little more work up front and add all devices’ hardware
addresses to a database, hosts in an internetwork can be assigned VLAN assignments dynamically.
By using intelligent management software, you can enable hardware (MAC) addresses,
protocols, or even applications to create dynamic VLANs. A
dynamic VLAN
will tell the
switch port which VLAN it belongs to, based on the MAC address of the device that connects
to the port.
For example, suppose MAC addresses have been entered into a centralized VLAN management
application. If a node is then attached to an unassigned switch port, the VLAN
management database can look up the hardware address and assign and configure the
switch port to the correct VLAN. This can make management and configuration easier for
the administrator. If a user moves, the switch automatically assigns them to the correct
VLAN. However, more administration is needed initially to set up the database than to set
up static VLANs, and additional administration is required for upkeep of the database.
Cisco administrators can use the VLAN Management Policy Server (VMPS) service to set up
a database of MAC addresses that can be used for the dynamic addressing of VLANs. VMPS
is a MAC-address-to-VLAN mapping database.