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Configuring voice VLANs
About voice VLANs
A voice VLAN is used for transmitting voice traffic. The device can configure QoS parameters for
voice packets to ensure higher transmission priority of the voice packets.
Common voice devices include IP phones and integrated access devices (IADs). This chapter uses
IP phones as an example.
Working mechanism
When an IP phone accesses a device, the device performs the following operations:
1. Identifies the IP phone in the network and obtains the MAC address of the IP phone.
2. Advertises the voice VLAN information to the IP phone.
After receiving the voice VLAN information, the IP phone performs automatic configuration. Voice
packets sent from the IP phone can then be transmitted within the voice VLAN.
Methods of identifying IP phones
Devices can use the OUI addresses or LLDP to identify IP phones.
Identifying IP phones through OUI addresses
A device identifies voice packets based on their source MAC addresses. A packet whose source
MAC address complies with an Organizationally Unique Identifier (OUI) address of the device is
regarded as a voice packet.
You can use system default OUI addresses (see Table 1) or configu
re OUI addresses for the device.
You can manually remove or add the system default OUI addresses.
Table 1 Default OUI addresses
Number OUI address Vendor
1 0001-e300-0000 Siemens phone
2 0003-6b00-0000 Cisco phone
3 0004-0d00-0000 Avaya phone
4 000f-e200-0000 H3C Aolynk phone
5 0060-b900-0000 Philips/NEC phone
6 00d0-1e00-0000 Pingtel phone
7 00e0-7500-0000 Polycom phone
8 00e0-bb00-0000 3Com phone
Typically, an OUI address refers to the first 24 bits of a MAC address (in binary notation) and is a
globally unique identifier that IEEE assigns to a vendor. However, OUI addresses in this chapter are
addresses that the system uses to identify voice packets. They are the logical AND results of the
mac-address and oui-mask arguments in the voice-vlan mac-address command.
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