Voice vlan assignment modes – H3C Technologies H3C S5120 Series Switches User Manual

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In general, as the first 24 bits of a MAC address (in binary format), an OUI address is a globally

unique identifier assigned to a vendor by IEEE. OUI addresses mentioned in this document,

however, are different from those in common sense. OUI addresses in this document are used by

the system to determine whether a received packet is a voice packet. They are the results of the

AND operation of the two arguments mac-address and oui-mask in the voice vlan mac-address

command.

You can remove the default OUI address of a device manually and then add new ones manually.

Voice VLAN Assignment Modes

A port can be assigned to a voice VLAN in one of the following two modes:

In automatic mode, the system matches the source MAC address carried in the untagged packets

sent when an IP phone is powered on against the device’s OUI addresses. If a match is found, the

system automatically assigns the receiving port to the voice VLAN, issues ACL rules and

configures the packet precedence. You can configure voice VLAN aging time on the device. The

system will remove a port from the voice VLAN if no packet is received from the port during the

aging time. Assigning/removing ports to/from a voice VLAN are automatically performed by the

system. The automatic mode is suitable for scenarios where PCs and IP phones connected in

series access the network through the device and ports on the device transmit both voice traffic

and data traffic at the same time, as shown in

Figure 2-1 PCs and IP phones connected in series access the network

In manual mode, you need to manually assign an IP phone accessing port to a voice VLAN. Then,

the system matches the source MAC addresses carried in the packets against the device’s OUI

addresses. If a match is found, the system issues ACL rules and configures the packet precedence.

In this mode, assigning/removing ports to/from a voice VLAN are performed manually. The manual

mode is suitable for scenarios where only IP phones access the network through the device and

ports on the device only transmit voice traffic, as shown in

. In this mode, ports assigned

to a voice VLAN transmit voice traffic exclusively, which prevents the impact of data traffic on the

transmission of voice traffic.