H3C Technologies H3C S3600 Series Switches - Manual (Page 138)

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3) On acquiring the voice VLAN ID and NCP address from DHCP Server 1, the IP phone
communicates with the specified NCP to download software, ignores the IP address assigned by
DHCP Server 1, and sends a new DHCP request message carrying the voice VLAN tag to the
voice VLAN.
4) After receiving the DHCP request, DHCP Server 2 residing in the voice VLAN assigns a new IP
address to the IP phone and sends a tagged response message to the IP phone. After the IP phone
receives the tagged response message, it sends voice data packets tagged with the voice VLAN
tag to communicate with the voice gateway. In this case, the port connecting to the IP phone must
be 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 ID
to be set is consistent with that of the switch and the NCP is reachable to the IP address to be set.
How S3600 Series Switches Identify Voice Traffic
S3600 series Ethernet switches determine whether a received packet is a voice packet by checking its
source MAC address against an organizationally unique identifier (OUI) list. If a match is found, the
packet is considered as a voice packet. Ports receiving packets of this type will be added to the 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 which
vendor a device belongs to according to the OUI address which forms the first 24 bits of a MAC address.
S3600 series Ethernet switches support OUI address mask configuration. You can adjust the matching
depth of MAC address by setting different OUI address masks.
The following table lists the five default OUI addresses on S3600 series switches.
Table 1-1 Default OUI addresses pre-defined on the switch
Number OUI address Vendor
1 0003-6b00-0000 Cisco phones
2 000f-e200-0000 H3C Aolynk phones
3 00d0-1e00-0000 Pingtel phones
4 00e0-7500-0000 Polycom phones
5 00e0-bb00-0000 3Com phones