1-3tag to communicate with the voice gateway. In this case, the port connecting to the IP phone mustbe configured to allow the packets tagged with the voice VLAN tag to pass.z An untagged packet carries no VLAN tag.z A tagged packet carries the tag of a VLAN.To set an IP address and a voice VLAN for an IP phone manually, just make sure that the voice VLAN IDto be set is consistent with that of the switch and the NCP is reachable to the IP address to be set.How Switch 5500-EI Series Switches Identify Voice TrafficSwitch 5500-EI series Ethernet switches determine whether a received packet is a voice packet bychecking its source MAC address against an organizationally unique identifier (OUI) list. If a match isfound, the packet is considered as a voice packet. Ports receiving packets of this type will be added tothe voice VLAN automatically for transmitting voice data.You can configure OUI addresses for voice packets or specify to use the default OUI addresses.An OUI address is a globally unique identifier assigned to a vendor by IEEE. You can determine whichvendor a device belongs to according to the OUI address which forms the first 24 bits of a MAC address.Switch 5500-EI series Ethernet switches support OUI address mask configuration. You can adjust thematching depth of MAC address by setting different OUI address masks.The following table lists the five default OUI addresses on Switch 5500-EI series switches.Table 1-1 Default OUI addresses pre-defined on the switchNumber OUI address Vendor1 0003-6b00-0000 Cisco phones2 000f-e200-0000 H3C Aolynk phones3 00d0-1e00-0000 Pingtel phones4 00e0-7500-0000 Polycom phones5 00e0-bb00-0000 3Com phonesSetting the Voice Traffic Transmission PrecedenceIn order to improve the transmission quality of voice traffic, the switch by default re-marks theprecedence of the traffic in the voice VLAN as follows:z Set the CoS (802.1p) precedence to 6.
