Voice Vlan Assignment Modes - 3Com 4500G Family Configuration Manual

Number
7
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 3-1 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
to a voice VLAN transmit voice traffic exclusively, which prevents the impact of data traffic on the
transmission of voice traffic.
OUI address
00e0-bb00-0000
Figure 3-1.
3-2
Vendor
3Com phone
Figure 3-2. In this mode, ports assigned