Information Technology Reference
In-Depth Information
Note:
Figure 5-1 shows the DHCP server, TFTP server, and CME router as three separate
devices. To save resources, smaller networks typically combine all three of these functions
into one device. In this case, the CME router also acts as the DHCP and TFTP server for
the network.
To meet the demands of this boot process, we put the following configuration in place
over the previous two chapters:
Voice VLAN
■
DHCP services
■
TFTP services
■
Voice VLAN
To separate the voice and data traffic, you must configure each port connecting to a Cisco
IP Phone for a voice VLAN. In Example 5-1, the voice VLAN is 100 and the data VLAN
(for the PC device attaching to the IP phone) is 200.
Example 5-1
Configuring Voice VLANs
Switch#
configure terminal
Switch(config)#
interface fa0/1
Switch(config-if)#
switchport mode access
Switch(config-if)#
switchport voice vlan 100
Switch(config-if)#
switchport access vlan 200
Switch(config-if)#
spanning-tree portfast
DHCP Services
After the IP phone receives its voice VLAN information, it begins sending DHCP requests.
The configuration in Example 5-2 enables a Cisco router to become a DHCP server for the
voice VLAN and deliver the needed IP address information to the IP phones.
Example 5-2
Configuring a DHCP Scope on a Router
ROUTER(config)#
ip dhcp pool VOICE_SCOPE
ROUTER(dhcp-config)#
network 172.16.1.0 255.255.255.0
ROUTER(dhcp-config)#
default-router 172.16.1.1
ROUTER(dhcp-config)#
option 150 172.16.1.1
ROUTER(dhcp-config)#
dns-server 4.2.2.2
