VLAN Tagging

VLAN Tagging allows an individual port or interface on the IMG to be part of multiple VLANs. When configured, each outgoing packet is tagged before leaving the IMG with a VLAN ID tag compliant to IEEE 802.1Q VLAN specifications. The VLAN Aware Ethernet Switch or router extracts the tag and routes the packet into the correct VLAN Group. Feature F-5601 Support for VLAN allows a user the choice of whether or not packets leaving the IMG have a VLAN ID tag inserted in its header. Through the GCEMS application the user can specify the VLAN 16 bit Tag Control Information (TCI) that will be assigned to either each individual interface (CTRL/SIG/DATA) or each individual IP address. All packets leaving either the specific interface or with a specific IP address will have a VLAN tag with the TCI information inserted in the ethernet header. Refer to the information below and the topics in the Related Items section below for more information on this feature.





In the diagram above the DATA interface is configured for VLAN Tagging. The configuration below describes the configuration needed to accomplish the diagram above. From diagram above, packets leaving the Data interface are tagged with a VLAN Identifier and sent to the router. The router reads the VLAN ID and routes the packets to the correct VLAN.





The configuration below will configure a VLAN Tag of 123 on any packets leaving the Data interface with an IP address of and a VLAN Tag of 314 on any packets leaving the SIG interface with IP address of The procedure below assumes the Logical IMG object and Physical IMG object have already been configured.


  1. Right click on the Physical IMG Name object and select New Network. The IP Network object that gets created is a container object and no configuration is needed here. Refer to IP Network (Interface) topic for more information on this object.
  2. Right click on the IP Network object created and select New IP Address. Modify the Physical Interface field to display VoIP Module 0 or 1. Enter an IP address and Default Gateway IP address for the VoIP Module being created.
  3. Click in the VLAN ID field and a Range Dialog box appears. Enter the VLAN ID by either using the slide rule or simply entering the ID in to the ID field. Select OK.

Note: The default value of the VLAN field is set to 0 which identifies the VLAN tagging as disabled.

  1. After configuring the VLAN ID, a new field labeled VLAN Priority appears in the VoIP module object being created. Select from drop down menu the priority being given to this VLAN Tag. The priority given will indicate a priority level that will be given to the packet. A priority of 7 is highest and priority of 0 is the lowest. These values can be used to prioritize different classes of traffic (voice, video, data, etc). See screen capture below of configured VoIP Module using the Data Interface with a VLAN tag of 123.


  1. Right click on the IP Network object again and select New IP Address. Modify the CPU - Data object so the Data interface is used again but the CPU is now in the Physical Interface field. The VLAN ID for this is ID:314 and the priority is 3. See screen capture below


  1. The VLAN tag configuration for the diagram is now complete. This procedure can be used on any interface/ip address to add a VLAN Tag to the ethernet packets leaving the interface using a specific IP address.


Additional Information


  1. When the VLAN tag is configured on the IMG, a VLAN Tag is inserted as shown in screen capture above. The tag is inserted between the Source Address and Ethernet Type information.

  2. The Tag Protocol Identifier (TPID) is set to 0x8100 (default) in order to identify the frame as an IEEE 802.1Q tagged frame.

  3. The priority of the tag is set through the ClientView application using the VLAN Priority field. The priority is set up through IEEE 802.1Q and is a way for administrators of a network to prioritize each packet being sent.

  4. The Canonical Format Indicator (CFI) will always have a value of zero. Zero indicates data is going over ethernet.

  5. VLAN ID is the ID configured in the VLAN ID field in the Web GUI application.