to a traditional telephony device, such as an analog telephone. The gateways themselves must have IP connectivity. In Figure , the first router has these configuration settings: The second router is configured with similar settings: Based on this information, this configuration is applied to the first router: hostname R1
interface FastEthernet 0/0
ip address 10.1.1.1 255.255.255.0
!
dial-peer voice 1 pots
destination-pattern 1111
port 1/0/0
!
dial-peer voice 2 voip
destination-pattern 2222
session target ipv4:10.2.2.2
! The second router has these configuration commands: hostname R2
interface FastEthernet 0/0
ip address 10.2.2.2 255.255.255.0
!
dial-peer voice 1 pots
destination-pattern 2222
port 1/0/0
!
dial-peer voice 2 voip
destination-pattern 1111
session target ipv4:10.1.1.1
! The voice-specific commands in the configurations (two dial peers in each configuration) are highlighted in gray. A dial peer describes where to find a telephone number, and the collection of all dial peers makes up the call routing table of a voice gateway. Two types of dial peers are shown in this example: POTS dial peers and VoIP dial peers. POTS dial peers indicate that the telephone number that is specified in the dial peer is found at a physical port. A VoIP dial peer refers to the IP address of a VoIP device. Figures and list the commands used for dial peers. The Voice-Specific Commands table provides details. Voice-Specific Commands Command Description dial-peer voice tag type Use the dial-peer voice command to enter the dial peer subconfiguration mode. The tag value is a number that must be unique for all dial peers within the same gateway. The type value indicates the type of the dial peer (for example, POTS or VoIP). destination-pattern telephone_number The destination-pattern command, entered in dial peer subconfiguration mode, defines the telephone number that applies to the dial peer. A call that is placed to this number is routed according to the configuration type and port (in the case of a POTS type dial peer) or session target (in the case of a VoIP type dial peer) of the dial peer. port port-number The port command, entered in POTS dial peer subconfiguration mode, defines the port number that applies to the dial peer. Calls that are routed using this dial peer are sent to the specified port. The port command can be configured only on a POTS dial peer. session target ipv4:ip-address The session target command, entered in VoIP dial peer subconfiguration mode, defines the IP address of the target VoIP device that applies to the dial peer. Calls that are routed using this dial peer are sent to the specified IP address. The session target command can be configured only on a VoIP dial peer.
Content 2.6 VoIP Lab Exercises 2.6.1 Lab 2.1 Configure CME using the CLI and Cisco IP Communicator Lab Activity Lab Exercise: Lab 2.1 Configure CME using the CLI and Cisco IP Communicator In this lab, you will configure Cisco Unified Call Manager Express using the IOS command line. On the two hosts, you will install Cisco IP Communicator and have one host call the other. Cisco IP Communicator is a software telephony application to simulate a Cisco IP Phone on the desktop of a PC running Microsoft Windows. This lab uses Cisco’s newest version of Cisco Unified Call Manager Express at the time of this writing (CME 4.0(2)) which was tested using Cisco IOS Release 12.4(9)T1 running on a Cisco 2800 Series router. The IP Voice image is required in order to be able to manipulate codecs.
Content Summary This module describes VoIP networks and the different components these networks use in order to be able to reliably enable voice calls. Converting analog voice signals to digital format and digital signals back to analog format is explained, along with the DSP modules that can be used to perform conversion by sampling, quantization, and encoding. The option of compression is also explained. Voice transport and voice encapsulation are described, and the module lists formulas for calculating the total bandwidth required for VoIP calls. Total bandwidth depends on the different codecs that are used. The module explains the different available IP telephony deployment models in terms of enterprise voice implementations, Cisco router voice gateway functions, Cisco Unified CallManager functions, and Call Admission Control.