15

The router is now configured to start in the new configuration.
Configuring the Fast Ethernet Interface
To configure the Fast Ethernet interface, follow these steps, beginning in global configuration mode:
Configuring a Dial Plan
Use a dial plan to map the destination telephone numbers with the voice ports on the router. In North America, the North
American Numbering Plan (NANP) is used, which consists of an area code, an office code, and a station code. Area codes are
assigned geographically, office codes are assigned to specific switches, and station codes identify specific ports on each switch.
The format in North America is 1Nxx-Nxx-xxxx, with N = digits 2 through 9 and x = digits 0 through 9. Internationally, each
country is assigned a one- to three-digit country code; the country’s dialing plan follows the country code.
In corporate environments, VoIP can be configured to recognize extension numbers and expand them into their full E.164
(international public telecommunications numbering plan) dialed numbers by using two commands in tandem:
destination-pattern and num-exp. Before you configure these two commands, map individual telephone extensions with their
full E.164 dialed numbers. You can do this easily by creating a number expansion table.
For Cisco voice implementations, three types of dial peers are used to match a dialed number to either a local telephony port or
a remote IP address:
•A POTS dial peer associates a physical voice port with a local telephone device. The key commands that you need to
configure are the port and destination-pattern commands, as in the following example:
Router(config)# dial-peer voice 401 pots
Router(config-dial-peer)# destination-pattern 14085553737
Router(config-dial-peer)# port 0/0
The destination-pattern command defines the telephone number associated with the POTS dial peer. The port command
associates the POTS dial peer with a specific logical dial interface, normally the voice port connecting your router to the
local POTS network.
•A VoIP dial peer associates a telephone number with an IP address. The key commands that you need to configure are the
destination-pattern and session target commands, as in the following example:
Router(config)# dial-peer voice 501 voip
Router(config-dial-peer)# destination-pattern 1919555....
Router(config-dial-peer)# session target ipv4:192.168.11.3
The destination-pattern command defines the telephone number associated with the VoIP dial peer. The session target
command specifies a destination IP address for the VoIP dial peer.
•A Voice over Frame Relay (VoFR) dial peer associates a telephone number with a Frame Relay data-link connection
identifier (DLCI). The key commands you need to configure are the destination-pattern and session target commands, as in
the following example:
Router(config)# dial-peer voice 601 vofr
Router(config-dial-peer)# destination-pattern 14087677448
Router(config-dial-peer)# session target serial 0/0 100

Command Purpose

Step1 Router(config)# interface
fastethernet 0/0
Enter configuration mode for the Fast Ethernet interface.
Step2 Router(config-if)# ip address
20.20.20.20 255.255.255.0
Set the IP address and subnet mask for the Fast Ethernet
interface.
Step3 Router(config-if)# no shutdown Enable the Fast Ethernet interface.
Step4 Router(config-if)# exit Exit configuration mode for the Fast Ethernet interface.