DHCP Server 1, and sends a new DHCP request message carrying the voice VLAN tag to the
e VLAN.
ceiving 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
sends voice data packets tagged with the voice VLAN
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.
voic
4) After re
receives the tagged response message, it
tag to communicate with the voice gateway.
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
How Switch 4500 Series Switches Identify Voice Traffic
series Ethernet switches determine whether a received packet is a voice packet by
checking it source MAC address against an organizationally unique identifier (OUI) list. If a match is
to be set is consistent with that of the switch and the NCP is reachable to the IP address to be set.
Switch 4500
s
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
vendor a device belongs to according to the OUI address whic
by IEEE. You can determine which
h forms the first 24 bits of a MAC address.
Switch 45
Ethernet switches su
ress mask configuration.
adjust the
matching depth of MAC addr
rent OUI address mask
00 series
pport OUI add
You can
ess by setting diffe
s.
The following table lists the five default
resses on Switch 4500
Table 10-1
Default OUI addresse
n the switch
OUI add
series switches.
s pre-defined o
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
10-3