3Com 2928 User Guide - Page 182

1 Voice VLAN Configuration Overview A voice VLAN is dedicated to voice traffic. After assigning the ports connecting to voice devices to a voice VLAN, you can configure quality of service (QoS) parameters for the voice traffic, thus improving transmission priority and ensuring voice quality. A device determines whether a received 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 1-1 for voice traffic identification. Table 1-1 The default OUI list Number 1 2 3 4 5 6 7 OUI Address 0001-e300-0000 0003-6b00-0000 0004-0d00-0000 00d0-1e00-0000 0060-b900-0000 00e0-7500-0000 00e0-bb00-0000 Vendor Siemens phone Cisco phone Avaya phone Pingtel phone Philips/NEC phone Polycom phone 3com phone z Generally, an OUI is 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 details, see Adding OUI Addresses to the OUI List. z 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 these two modes: Automatic mode and manual mode. Ports on a same device can be assigned to VLANs in different modes. 1-1