Chapter 4
Configuring Voice-over-IP
Step 5
If you have not configured the router before, or want to change the configuration, use Cisco IOS
commands to configure global parameters, passwords, network management, and routing protocols. In
this example, IP routing is enabled:
Router(config)# ip routing
For complete information about global configuration commands, refer to the Cisco IOS configuration
guides and command references.
Step 6
If you have not already done so, configure the network module or WAN interface card that you plan to
use for IP traffic. For instructions, see your router's installation and configuration guide or the
configuration note for the network module or WAN interface card.
Step 7
To configure another interface, enter the exit command to return to the
Step 8
To configure the router for voice traffic, refer to the detailed instructions in the Voice over IP
Configuration document.
Step 9
When you finish configuring interfaces, exit configuration mode and return to the enable prompt by
pressing Ctrl-z. To see the current operating configuration, including any changes you just made, enter
the show running-config command:
Router# show running-config
To see the configuration currently stored in NVRAM, enter the show startup-config command at the
enable prompt:
Router# show startup-config
Step 10
The results of the show running-config and show startup-config commands differ from each other if
you have made changes to the configuration, but have not yet written them to NVRAM. To write your
changes to NVRAM, making them permanent, enter the copy running-config startup-config command
at the enable prompt:
Router# copy running-config startup-config
Building configuration. . .
[OK]
Router#
The router is now configured to boot in the new configuration.
Voice-over-IP Configuration Examples
The actual VoIP configuration procedure you complete depends on the topology of your voice network.
The following configuration examples should give you a starting point. Of course, these configuration
examples would need to be customized to reflect your network topology.
Configuration procedures are supplied for the following scenarios:
•
•
•
•
•
These examples are described in the following sections.
OL-1957-04
FXS-to-FXS Connection Using RSVP, page 4-4
Linking PBX Users with E&M Trunk Lines, page 4-6
PSTN Gateway Access Using FXO Connection, page 4-8
PSTN Gateway Access Using FXO Connection (PLAR Mode), page 4-9
Configuring Direct-Inward Dialing on a BRI Port, page 4-10
Software Configuration Guide for Cisco 2600 Series, Cisco 3600 Series, and Cisco 3700 Series Routers
prompt.
Router(config)#
4-3