Configuring Voice over IP

When you start a Cisco VG200 gateway, it automatically detects the voice network modules and voice interface cards that have been installed. The first time you use a Cisco VG200 gateway, you will need to configure each voice port that you want to enable. After configuring each port, if you replace a card or module with a card or module of the same type, the gateway will recognize the new hardware component and use the previous configuration settings.

You must configure the Cisco VG200 software for each new interface or if you want to change the configuration of an existing interface.

If you replace a module that was already configured, the gateway recognizes it and brings up the interface in the existing configuration.

To configure a voice interface, you must use configuration mode (manual configuration). In this mode, you can enter Cisco IOS command-line interface (CLI) commands at the gateway prompt.

Perform the following steps to enter configuration mode (manual configuration):

Step 2 Power ON the gateway. If the current configuration is no longer valid, after about one minute you will see the following prompt:

Would you like to enter the initial dialog? [yes/no]: 
 

Step 3 Enter no. You now enter the normal operating mode of the gateway.

Note If the current configuration is valid, you enter normal operating mode automatically.

Step 4 After a few seconds, you see the user EXEC prompt (VG200>). Enter enable and the password to enter privileged EXEC mode, as follows:

VG200> enable
Password: <password>
 

Configuration changes can be made only in privileged EXEC (enable) mode. When you enter privileged EXEC mode, the prompt changes to the host name followed by a pound sign (#), such as VG200#.

Step 5 Enter the commands required to configure the voice interface cards installed in the VG200, as described in the following sections:

VG200# copy running-config startup-config
Building configuration. . .
[OK]
VG200# 
 

The gateway is now configured to boot in the new configuration.

VG200(config)# dial-peer voice 1 pots
VG200(config-dial-peer)# application MGCPAPP
VG200(config-dial-peer)# port 1/1/0

VG200(config)#mgcp
VG200(config)#mgcp call-agent hostname 
 

To enable support for Cisco CallManager within MGCP, enter the following command:

VG200(config)#ccm-manager redundant-host hostname1  hostname2
 

Where hostname1 identifies the first backup Cisco CallManager server in dotted decimal format, and hostname2 identifies the second backup Cisco CallManager server.

Note that all dial-plan related configuration elements are controlled by Cisco CallManager, and should not be configured in the Cisco VG200 gateway for MGCP-managed endpoints (those with application MGCPAPP in the dial-peer statement). If you are familiar with configuring H.323 endpoints, you should not configure any of the following:

• Destination pattern

• Session target

• Expansion numbers

• Connection PLAR/tie line/trunk (voice port)

• CODEC

If you configure one or two backup Cisco CallManager servers, you can control how the gateway behaves if the primary server becomes unavailable at some point and then later becomes available again: this is called switchback.

VG200(config)#ccm-manager switchback
 {graceful|imm[ediate]|sch[edule-time] hh:mmm|uptime[-delay] minutes}
 

Table 3-1: Switchback Command Options

Switchback Command Option	Function
graceful	Completes all outstanding calls before returning the gateway to the control of the primary Cisco CallManager server.
immediate	Returns the gateway to the control of the primary Cisco CallManager server without delay, as soon as the network connection to the server is reestablished.
schedule-time hh:mm	Returns the gateway to the control of the primary Cisco CallManager server at the specified time, where hh:mm is the time according to a 24-hour clock. If the configured schedule time is earlier than the time at which the gateway reestablishes a network connection to the primary server, the switchback will occur at the specified time on the following day.
uptime-delay minutes	Returns the gateway to the control of the primary Cisco CallManager server when the primary server runs for a specified number of minutes after a network connection is reestablished to the primary server. The range of permitted values is from 1 to 1440 (1 minute to 24 hours).

VG200(config)#ccm-manager switchover-to-backup
 

In this case, the switchover will occur immediately. Note that this command will not switch the gateway to the backup Cisco CallManager server if you have the switchback option set to immediate and the primary Cisco CallManager server is still running.

VG200(config) MGCP call-agent hostname|ipaddress 
VG200(config) MGCP dtmf-relay
 

1. Identify the T1 port number and enter the information provided by your local carrier.

2. Assign timeslots to the DS-0 group and identify the emulation type.

3. Configure local H.323 endpoints connected to the Cisco VG200 voice ports.

4. Configure H.323 endpoints connected by means of the Cisco VG200 Ethernet port.

5. Direct calls using wildcard destination patterns, as needed.

6. Complete and save the configuration.

In addition, make sure that you configure Cisco CallManager correctly to provision the Cisco VG200 as an H.323 gateway, with route patterns configured to route T1-CAS calls to a Cisco VG200 gateway.

To configure a route pattern using Cisco CallManager Administrator, select Dial Plan/Route Pattern and enter the route pattern. Then select the Cisco VG200 gateway, set the Route Option to Route this pattern, and specify the Network Location to be OnNet or OffNet.

For a detailed description about configuring Cisco CallManager, refer to the Cisco CallManager Administration Guide.

The following procedure describes in detail how to perform H.323 T1 configuration using Cisco IOS CLI commands.

However you configure the T1 port, you first identify the port number and then enter the configuration information provided by your telco, as in the following example:

VG200(config)# controller T1 1/port#
VG200(config-controller)# framing esf
VG200(config-controller)# clock source internal
VG200(config-controller)# linecode b8zs
 

You can define each DS-0 group to use FXS, FXO, or E&M, using the following command:

VG200(config-controller)# dso-group group<groupnumber> timeslots <timeslotnumber> type emulationtype
 

Replace <groupnumber> with the DS-0 group number, and replace <timeslotnumber> with the number of DS-0 timeslots to allocate to the group. For example, the following command configures the first DS-0 group with one timeslot using FXS emulation in loop-start mode:

VG200(config-controller)# dso-group 0 timeslots 1 type fxs-loop-start
 

For example, the following command assigns 12 timeslots to DS-0 group 1:

VG200(config-controller)# dso-group 1 timeslots 1-12 type fxs-loop-start
 

To configure plain old telephone service (POTS) dial peers, use the following command string:

VG200(config)# dial-peer voice <number> pots 
VG200(config-dial-peer)# destination-pattern endpoint#
VG200(config-dial-peer)# port 1/<portnumber>:<DS0groupnumber>
 

Replace<number> with a unique numeric identifier for each dial peer, and replace endpoint# with the E.164 telephone extension of the POTS dial peer. Replace <portnumber> with 0 or 1 depending on which T1 port you are using. Replace <DS0groupnumber> with a numeric digit from 0 to 23 for each DS-0 group you are configuring.

For example, the following commands could be used to route all calls with the prefix 222 to the DS-0 hunt group 1 of controller T1 1/0:

VG200(config)# dial-peer voice 222 pots 
VG200(config-dial-peer)# destination-pattern 222.... 
VG200(config-dial-peer)# port 1/0:1
VG200(config-dial-peer)# prefix 222
 

The prefix command at the end is required to replace the digits that the gateway strips off from the dialed digit string based on the wildcard destination pattern.

Step 4 Configure H.323 endpoints connected to the Cisco VG200 Ethernet port.

To configure H.323 endpoints, use the following command string:

VG200(config)# dial-peer voice <number>  voip 
VG200(config-dial-peer)# destination-pattern <endpointnumber> 
VG200(config-dial-peer)# session target {ipv4:ipaddress|dns:hostname}
VG200(config-dial-peer)# codec codecid
 

For example, the following commands assign extension 2001 to the IP device with the network address 192.168.100.1:

VG200(config)# dial-peer voice 1 voip 
VG200(config-dial-peer)# destination-pattern 2001
VG200(config-dial-peer)# session target ipv4:192.168.100.1 
VG200(config-dial-peer)# codec g711u1aw
 

You can use wildcard destination patterns to simplify your dial plan configuration. For instance, you can direct all incoming calls starting with specific digits, such as "525," to a Cisco CallManager configured as an H.323 endpoint. You might direct all calls starting with a "9" to voice ports connected to the PSTN, or direct all calls beginning with an "8" to a PBX.

VG200(config-dial-peer)# destination-pattern pattern ....
 

For example, the following command directs all calls starting with 525 to a Cisco CallManager with the DNS host name CCM30:

VG200(config-dial-peer)# destination-pattern 525....
VG200(config-dial-peer)# session target dns:CCM30 
 

The number of digits in that you substitute for pattern plus the number of periods in the wildcard (...) must match the total number of digits configured for use by the gateway in Cisco CallManager Administrator. Also, keep in mind that the numbers that you substitute for pattern are removed by the gateway. When the call is forwarded to the destination number, only the digits in the position of the wildcard pattern (...) will be received by the destination endpoint. If you want to replace the digits that are stripped off or (or add a different set of digits), use the prefix command.

Step 6 Complete and save the configuration by entering the following commands:

VG200# line con 0
VG200# transport input none
VG200# line aux 0
VG200# line vty 0 4
VG200# login
VG200# no scheduler allocate
VG200# end
VG200# copy running-config startup-config
Building configuration. . .
[OK]
VG200#