Voice End-Points
To have a voice VLAN work properly, the voice devices, such as a Cisco phones and VoIP endpoints, must be assigned to the voice VLAN where it sends and receives its voice traffic. Some of the possible scenarios are as follows:
- A phone/endpoint may be statically configured with the voice VLAN.
- A phone/endpoint may obtain the voice VLAN in the boot file it downloads from a TFTP server. A DHCP server may specify the boot file and the TFTP server when it assigns an IP address to the phone.
- A phone/endpoint may obtain the voice VLAN information from CDP and LLDP-MED advertisements it receives from their neighbor voice systems and switches.
The switch expects the attaching voice devices to send voice VLAN, tagged packets. On ports where the voice VLAN is also the native VLAN, voice VLAN untagged packets are possible.