165To identify the voice VLAN advertised by LLDP, execute the display lldp local-information command, andexamine the MED information fields in the command output.The LLDP packets that the device send to IP phones carry the priority information, but the CDP packets thatthe device send to IP phones do not carry the priority information.Configuration procedureTo configure LLDP to advertise a specific voice VLAN:Step Command Remarks1. Enter system view. system-view N/A2. Enter interface view or portgroup view.• Enter Layer 2 Ethernet interfaceview:interface interface-typeinterface-number• Enter port group view:port-group manualport-group-nameUse one of the commands.3. Configure LLDP to advertise aspecific voice VLAN. lldp voice-vlan vlan-idBy default, LLDP advertises thevoice VLAN configured on theport.Dynamically advertising server-assigned VLANsthrough LLDPOverviewDynamic advertisement of server-assigned VLANs through LLDP must work with 802.1X or MACauthentication, and is available only for LLDP-enabled IP phones. If 802.1X authentication is used, makesure the IP phones also support 802.1X authentication.To implement this function for an IP phone, perform the following configuration tasks:• Enable LLDP globally and on the port connected to the IP phone.• Configure 802.1X or MAC authentication to make sure the IP phone can pass securityauthentication. For more information about 802.1X authentication, MAC authentication, and VLANassignment by servers, see Security Configuration Guide.• Configure VLAN authorization for the IP phone on the authentication server.After the IP phone passes authentication, LLDP advertises the server-assigned VLAN in the LLDP-MEDNetwork Policy TLV to the IP phone. The IP phone will send its traffic tagged with the assigned VLAN. Also,the port connected to the IP phone will be added to the server-assigned VLAN.Example for using 802.1X to authenticate IP phonesAs shown in Figure 54, configure 802.1X on the device to authenticate the host and the IP phone (whichmust support 802.1X). Configure the authentication server to assign an untagged VLAN to the host andassign a tagged VLAN to the IP phone. After the host and the IP phone pass the authentication, the port
