3Com Switch 7750 Configuration Guide

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VOICE VLAN CONFIGURATION
Voice VLAN Overview Voice VLANs are VLANs configured specially for voice data stream. By adding the
ports with voice devices attached to voice VLANs, you can perform QoS (quality of
service)-related configuration for voice data, ensuring the transmission priority of
voice data stream and voice quality.
Switch 7750 Ethernet switches determine whether a received packet is a voice
packet by checking its source MAC address. If the source MAC addresses of
packets comply with the organizationally unique identifier (OUI) addresses
configured by the system, the packets are determined as voice packets and
transmitted in voice VLAN.
You can configure an OUI address for voice packets or specify to use the default
OUI address.
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An OUI address is a globally unique identifier assigned to a vendor by IEEE. You
can determine which vendor a device belongs to according to the OUI address
which forms the first 24 bits of a MAC address.
The following table shows the five default OUI addresses of a switch.
You can create multiple voice VLANs and bind each voice VLAN to a port. In this
way, the voice traffic received by a port can be transmitted in the voice VLAN
bound to the port. This feature allows you to manage voice traffic flexibly.
A voice VLAN can operate in two modes: automatic mode and manual mode. You
can configure the operation mode for a voice VLAN according to data stream
passing through the ports of the voice VLAN.
■ In automatic mode: Switch 7750s automatically add a port connecting a IP
voice device to the voice VLAN through learning the source MAC address in the
untagged packet sent by the IP voice device when it is powered on. When the
aging time of a port expires, voice ports on which the OUI addresses are not
updated (no voice stream passes) will be automatically removed from the voice
Table 57 Default OUI addresses preset by the switch
Number OUI Address Vendor
1 0003-6b00-0000 Cisco phone
2 000f-e200-0000 3Com Aolynk phone
3 00d0-1e00-0000 Pingtel phone
4 00e0-7500-0000 Polycom phone
5 00e0-bb00-0000 3com phone