Configuring Automatic VLAN Assignment via DHCP Chapter 9: Network Requirements and Preparation
9.8 Configuring Automatic VLAN Assignment via
You can configure an IP phone to automatically determine its VLAN id via DHCP. When
the phone boots for the first time, it will acquire an IP address via DHCP similar to any
other network device. However, the DHCP response will also specify (using a proprietary
DHCP option), the VLAN id for the phone to use. Then, the phone will release the IP
address originally assigned to it and will reboot. After reboot, all packets are tagged with
the VLAN id specified in the original DHCP response.
This feature affects the following phones: IP110/115/210/212k/230/530/560/560g
The following phones are unaffected by this feature: AP100, IP100
The Automatic VLAN Assignment feature is not configured through ShoreWare Director.
Configuration changes are performed at the DHCP server. Parameters related to Automatic
VLAN Assignment (along with their supporting text) have been italicized in the procedure
that follows to make them easier to spot.
To configure Automatic VLAN Assignment via DHCP on a Microsoft DHCP server:
Step 1 Open DHCP Manager on your Microsoft DHCP server.
Step 2 Right-click the DHCP server and select Set pre-defined options.
Step 3 Click Add.
Step 4 Set Name to IP Phone Boot Server.
Step 5 Set Data Type to String.
Step 6 Set Code to 156 and add a description, if desired.
Step 7 Navigate to the scope options and add option 156.
Step 8 Set the value of option 156 to:
ftpservers=ip address, Layer2Tagging=N, VlanId=X
FtpServers always needs to be set to a ShoreWare server and is a pre-existing
Layer2Tagging is a new parameter.
•Purpose: enable/disable 802.1Q, default is disabled
where N=0 is disable, N=1 is enable
VlanId is a new parameter.
•Purpose: VLAN id when 802.1Q is enabled, default is zero
where X is a VLAN id between 0 and 4094
E.g., the following would enable VLAN tagging using a VLAN id of 10: