Before turning on the IP phone, it is neccessary to pre-configure the switch.
IP phone traffic is divided into 2 types:
- Phone — traffic intended for the IP phone itself and all its services. Depending on settings, the traffic can be either tagged or untagged;
- Transit — traffic intended for devices behind the phone's PC port. It comes from the external network to the LAN port, then passes through IP phone in transit and exits from the PC port, and so in the opposite direction. By default, the traffic is untagged along the entire path through the phone's bridge. If VLAN is enabled for transit traffic, then this traffic is tagged on the LAN port side, and untagged on the PC port side, that is, the phone removes or adds a tag for this type of traffic.
Network settings are made in the web interface menu 'Network' → 'Internet'.
It is possible to activate VLAN for Phone traffic in the section 'LAN' → 'Use VLAN' section or via the LLDP protocol.
The LLDP protocol setting has priority over the configuration settings: that is, if a VLAN is configured for the phone traffic in the configuration, but the phone has received a network policy via LLDP, the network will be configured via LLDP.
It is possible to activate VLAN for Transit traffic in the section 'PC' → 'Use VLAN'.
A PC connected to the PC port has untagged traffic regardless of the configured scheme. When VLAN for Transit traffic is activated, the untagged traffic from the PC will be tagged when passing through the phone. And the tag will be removed when passing through the phone in the opposite direction.
Diagrams of network configuration options are shown below. The color shows the distribution of traffic by ports if different traffic comes to the ingress. If the traffic is not divided by purpose, then it is shown in one color in the diagram.
1. Diagram without using VLAN for Phone and Transit traffic:
In this case, the network is configured using DHCP or Static with VLAN disabled for Phone and Transit traffic. All traffic (shown as 'Phone + Transit' in the diagram) passing through the device will be untagged.
2. Diagram of using VLAN only for Phone traffic
In this case, the network is configured using DHCP or Static protocol with VLAN configured for Phone traffic. VLAN is disabled for Transit traffic. Traffic intended for the phone will be tagged. Transit traffic will be untagged.
3. Diagram of using VLAN only for Transit traffic
In this case, the network is configured using DHCP or Static protocol with VLAN disabled for Phone traffic. VLAN is enabled for Transit traffic. Traffic intended for the phone will be untagged. Transit traffic at the ingress and egress of the LAN port will be tagged, and at the ingress and egress of the PC port it will be untagged.
4. Diagram of using the same VLAN ID for Phone and Transit traffic
In this case, the network is configured using DHCP or Static protocol with VLAN enabled for Phone and Transit traffic with the same VLAN ID. Traffic intended for the phone will be tagged. Transit traffic at the ingress and egress of the LAN port will be tagged with the same VLAN ID as Phone traffic, and at the ingress and egress of the PC port it will be untagged.
5. Diagram of using different VLAN ID for Phone and Transit traffic
In this case, the network is configured using DHCP or Static protocol with VLAN enabled for Phone and Transit traffic with different VLAN ID. Traffic intended for the phone will be tagged with one VLAN ID. Transit traffic at the ingress and egress of the LAN port will be tagged with another VLAN ID, and at the ingress and egress of the PC port it will be untagged.