Table of Contents
Advertisement
Configuring a voice VLAN
Overview
The voice technology is developing quickly, and more and more voice devices are in use. In
broadband communities, data traffic and voice traffic are usually transmitted in the network at the
same time. Usually, voice traffic needs higher priority than data traffic to reduce the transmission
delay and packet loss ratio.
A voice VLAN is configured for voice traffic. After assigning the ports that connect to voice devices to
a voice VLAN, the system automatically modifies quality of service (QoS) parameters for voice traffic,
to improve the transmission priority of voice traffic and ensure voice quality.
NOTE:
Common voice devices include IP phones and integrated access devices (IADs). Only IP phones
are used in the voice VLAN configuration examples in this document.
OUI addresses
A device determines whether an incoming packet is a voice packet by checking its source MAC
address. If the source MAC address of a received packet matches an organizationally unique
identifier (OUI) in the voice device OUI list (referred to as the OUI list in this document) maintained by
the switch, the packet is regarded as a voice packet.
You can add OUI addresses to the OUI list maintained by the device or use the default OUI list shown
in
Table 51
Table 51 The default OUI list
Number
1
2
An OUI address is usually the first 24 bits of a MAC address (in binary format). It is a globally unique
identifier assigned to a vendor by the IEEE. In this document, however, OUI addresses are used by
the system to determine whether received packets are voice packets and they are the results of the
AND operation of a MAC address and a mask. For more information, see
the OUI
list."
You can remove default OUI addresses and if needed, add them to the OUI list after their removal.
Voice VLAN assignment modes
A port connected to a voice device, an IP phone for example, can be assigned to a voice VLAN in
one of the following modes:
•
Automatic mode—The system matches the source MAC addresses in the protocol packets
(tagged packets) sent by the IP phone upon its power-on against the OUI list. If a match is found,
the system automatically assigns the receiving port to a voice VLAN, issues ACL rules and
configures the packet precedence. You can configure an aging timer for the voice VLAN. The
system will remove the port from the voice VLAN when the aging timer expires if no voice
packet is received on the port during the aging timer. The system automatically assigns ports to,
or removes ports from, a voice VLAN. Automatic mode is suitable for scenarios where PCs and
for voice traffic identification.
OUI Address
0003-6b00-0000
00e0-7500-0000
127
Vendor
Cisco phone
Polycom phone
"Adding OUI addresses to
Hide quick links:
Advertisement
Table of Contents
