32 CHAPTER 4: VOICE VLAN CONFIGURATION GUIDE
Precautions ■You cannot add a port operating in automatic mode to the voice VLAN
manually. Therefore, if you configure a VLAN as a voice VLAN and a protocol
VLAN at the same time, you will be unable to associate the protocol VLAN with
such a port. Refer to “Configuring Protocol-Based VLAN” on page 23 for
description on protocol VLAN.
■You cannot set the voice VLAN as the default VLAN on a port in automatic
mode.
■The switch supports only one voice VLAN.
■You cannot enable voice VLAN on a port configured with the Link Aggregation
Control Protocol (LACP).
■Only a static VLAN can be configured as a voice VLAN.
■When the number of ACL rules applied to a port reaches the upper threshold,
enabling voice VLAN on the port fails. You can use the display voice vlan
error-info command to locate such ports.
■In the voice VLAN operating in security mode, the device allows only the
packets whose source address matches a recognizable voice device vendor OUI
to pass through. All other packets, including authentication packets such as
802.1x authentication packets, will be dropped. Therefore, you are
recommended not to transmit both voice data and service data in the voice
VLAN. If that is needed, disable the security mode of the voice VLAN.