How to configure an IP phone's VLAN using LLDP-MED

Zyxel_LuciousZyxel_Lucious Zyxel Official Agent Posts: 102  mod

The example shows administrators how to use LLDP-MED to configure an IP Phone’s VLAN ID. Any IP Phone connected to the switch will be assigned to the certain VLAN based on the switch’s port. In the following topic, we will also introduce other ways to send VOIP traffic into a specific (Voice) VLAN. Implementing VOIP allows administrators the option to prioritize Voice traffic during network congestions, thus, preventing poor voice quality or miscommunications between IP Phones.

Note:

All network IP addresses and subnet masks are used as examples in this article. Please replace them with your actual network IP addresses and subnet masks. This example was tested using XGS4600-32.


1. Configure VLAN for IP phone

1-1. Configure VLAN 100 on Switch. VLAN 100 is created for the IP Phone.

2. Configure the switch

2-1. Enter the web GUI and go to Menu > Advanced Application > LLDP > LLDP Configuration. Make sure that the LLDP configuration is active.

2-2. Enter web GUI and go to Menu > Advanced Application > LLDP > LLDP-MED Configuration. Check the “Network Policy” on port 1 (the port that connects to the IP Phone).

2-3. Enter the web GUI and go to Menu > Advanced Application > LLDP > LLDP-MED Network Policy. Key in the port number as 1 and the VLAN we want to assign the IP Phone to (VLAN 100) and leave DSCP as “0”. We can also set the Priority. Click “Add”.


3. Test the Result

3-1. Go to Menu > Management > MAC Table > Search. Check the MAC table. The IP Phone’s MAC address should be in VLAN 100.

3-2. Enter the web GUI and go to Menu > Management > Diagnostic > Ping test. Use Switch to ping the IP Phone. The switch can ping the IP Phone successfully.


4. What Could Go Wrong

4-1. If the MAC address of the IP Phone is not assigned to the VLAN 100 successfully, please check if the IP Phone supports LLDP-MED. LLDP-MED must be enabled on the switch.

4-2. Since the IP Phone is assigned a VLAN ID via the function of the Network Policy in LLDP-MED, The voice traffic from the switch must be tagged backed to the IP Phone. Port 1 in VLAN 100 on the Switch should be tagged out (Check TX tagging) so that the Switch can ping the IP Phone successfully.

4-3. Since the IP Phone is assigned a VLAN ID via the function of the Network Policy in LLDP-MED, please make sure the IP Phone either supports LLDP-MED, or has LLDP-MED enabled.

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