MGCP Configuration Server

When you are using the Configuration Server feature, the gateway- and interface-specific MGCP configuration commands are provided by CUCM in the form of an Extensible Markup Language (XML) configuration file that is downloaded by the Cisco IOS gateway from the CUCM TFTP server. This is the recommended approach to integrate Cisco IOS MGCP gateways with CUCM. The Cisco IOS gateway dynamically loads the necessary MGCP configuration commands from the XML file downloaded from the TFTP server.

When changes are made to the configuration in the CUCM database, a message is sent by CUCM to the MGCP gateway instructing the gateway devices to download the updated XML configuration file. Each device has an XML parser that interprets the XML file according to its device-specific requirements. Cisco MGCP gateways, for example, translate the content of the XML file into specific Cisco IOS commands for local execution.

Figure 10-3 illustrates the configuration and communication on and between CUCM and the MGCP gateway. Notice that the router requires only two configuration commands: ccm-manager config and ccm-manager config server ip-address.

Figure 1G-S MGCP Configuration Server Communication

Figure 1G-S MGCP Configuration Server Communication

Q.931 Backhaul

A distinguishing characteristic of ISDN interfaces is the common channel signaling (Q.931) carried in the D channel (channel 24 in PRI interfaces and channel 17 in E1 interfaces). The gateway does not process or change this signaling data; it just passes it to CUCM through what Cisco calls the Q.931 backhaul channel. The gateway is still responsible for the termination of the Layer 2 signaling (Q.921 link access procedure over the D channel [LAP-D]). The gateway will not bring up the D channel unless it can communicate with CUCM to backhaul the Q.931 messages contained in the D channel.

A Q.931 backhaul channel is a logical TCP connection between CUCM and Cisco MGCP gateways. Q.931 backhaul forwards the Q.931 signaling traffic from an ISDN interface on a gateway over TCP port 2727 to a CUCM configured as an MGCP call agent.

MGCP Gateway Configuration: CUCM

MGCP gateway implementation includes configuration steps on both the CUCM (MGCP call agent) and the MGCP gateway that will be controlled.

The CUCM configuration steps for implementing an MGCP gateway are as follows:

Step 1 Add the MGCP gateway to CUCM. Step 2 Configure the MGCP gateway in CUCM.

Step 3 Add one or more modules to the slots of the MGCP gateway in CUCM.

Step 4 Add voice interface cards, voice WAN interface cards, or high-density voice WAN interface cards to the configured modules.

Step 5 Configure the MGCP endpoints (one or more per voice interface card).

Follow these detailed configuration steps to add an MGCP gateway to CUCM:

Step 1 From CUCM Administration, choose Device > Gateway.

Step 2 Click the Add New button. The Add a New Gateway window will open.

Step 3 From the Gateway Type drop-down list, choose the appropriate MGCP gateway, as shown in Figure 10-4.

Step 4 Click Next.

Step 5 Choose MGCP from the Protocol drop-down menu and click Next.

Figure 10-4 displays the choosing of the Cisco 2811 router for an MGCP gateway configuration.

Figure 10-4 MGCP Gateway Configuration

Figure 10-4 displays the choosing of the Cisco 2811 router for an MGCP gateway configuration.

Figure 10-5 displays the selection of the MGCP protocol for the gateway configuration.

Figure 10-5 MGCP Gateway Protocol Selection

NOTE Some gateways support SCCP and MGCP, whereas few support only SCCP. The Protocol list box appears when adding a gateway that has support for both of these protocols. SCCP supports some features on analog FXS interfaces that are not available from MGCP-controlled FXS ports.

The configuration of an MGCP gateway depends on the selected platform. In Figure 10-4, a Cisco IOS 2811 router model has been selected.

The configuration of the MGCP gateway includes the following steps:

Step 1 Enter the hostname or fully qualified domain name of the gateway in the Domain Name field. The name has to match the hostname or the hostname and domain name (fully qualified domain name) of the Cisco IOS router.

Step 2 Enter a description for the gateway.

Step 3 Select a CUCM group.

Step 4 Configure the IDSN switch type.

Step 5 Click Save. Reset the gateway for the configuration changes to apply.

NOTE The ISDN switch type is configured globally in Cisco IOS routers. The ISDN switch type can also be set to a different value per ISDN interface. An interface command will always override the inheritance of a global command. The global ISDN switch type is also part of the gateway configuration in CUCM Administration. You can configure an interface-specific switch type at the MGCP endpoint level in CUCM Administration.

Figure 10-5 MGCP Gateway Protocol Selection

—Select the type of gateway you would like to add:

Gateway Type Cisco 2821

Change Gateway type

—Select the type of gateway you would like to add:

Gateway Type Cisco 2821

Change Gateway type

To display help for the configuration parameters, click ? on the page, or from the Help menu choose the For This Page option.

Figure 10-6 displays the MGCP Gateway Configuration page. Figure 10-6 MGCP Gateway Configuration

Enter gateway name

Select Cisco Unified Communications Manager Group Enter description

Enter gateway name

Select Cisco Unified Communications Manager Group Enter description

Configure global parameters

Get help for global parameters

Configure global parameters

Get help for global parameters

Endpoints are added by selecting voice modules and voice interface cards at the gateway configuration page. To add endpoints to a gateway, follow these steps:

Step 1 Locate the Configured Slots, VICs, and Endpoints section, and select the voice hardware module placed in the slot.

NOTE Only voice modules have to be specified. If data network modules are used in a slot, you do not have to select them.

Step 2 Click Save. The subunits (voice interface cards slots) of the selected voice module will display.

Step 3 For each subunit (voice interface cards slot), select the subunit.

Step 4 Click Save. The endpoints of the selected voice interface card will display.

Step 5 Repeat Steps 4 to 5 for each subunit of a module. Repeat Steps 2 to 5 for each module of the gateway.

Figure 10-7 shows the voice module and voice interface card (VIC) selection process.

Figure 10-7 MGCP Configuration

Select VIC (per module)

Gateway Configuration

Q Save Delete ^jjj Reset cjju Add New

..glnbalknnwledge.cnm ..global knowledge, en m

0/3/ 0 tí Module in Slot 1 Nnne s Module in Slot Z | < NonE >

MGCP endpoint(s) are shown and can be clicked for endpoint configuration

NOTE Use the Cisco IOS command show diag on the gateway to display the modules and interface cards that the gateway is equipped with.

After adding voice modules and VICs in the Configured Slots, VICs, and Endpoints section of the gateway, the configuration endpoints of the VICs are displayed.

To configure an MGCP endpoint, follow these steps:

Step 1 Click the endpoint identifier (for example, 0/3/0).

..glnbalknnwledge.cnm ..global knowledge, en m

Step 2 Select the device protocol or signaling for the endpoint. T1 and E1 interfaces support channel associated signaling (CAS) or command channel signaling (CCS) via ISDN PRI. Analog interfaces support ground-start and loop-start signaling. Select the protocol that should be used on the endpoint and click Next.

Step 3 Enter a description for the endpoint.

Step 4 Select the device pool that should be used by this endpoint.

Step 5 You can display help for any configuration parameters via Help > For This Page.

Step 6 Click Save. Reset the gateway for configuration changes to be committed to the gateway.

Figures 10-8 and 10-9 show an example of an MGCP E1 endpoint configuration.

MGCP Gateway Configuration: Cisco IOS Configuration

Two commands are required for a Cisco IOS MGCP gateway to pull its MGCP configuration from the CUCM TFTP server.

The command ccm-manager config server ip-address specifies the IP address of the TFTP configuration server. If more than one CUCM TFTP server is deployed in the cluster, a list of IP addresses can be specified using a space between each IP address. The Cisco IOS MGCP gateway prioritizes the IP addresses from left to right.

The command ccm-manager config enables the Configuration Server feature. The ccm-manager config server command is ignored without this command.

For the Configuration feature to work, the following prerequisites must be met:

■ The MGCP gateway and the CUCM TFTP server have IP connectivity.

■ The MGCP gateway and endpoints are configured in CUCM.

■ The hostname or fully qualified domain name (FQDN) of the Cisco IOS MGCP gateway has to match the CUCM MGCP gateway configuration.

If all these conditions are met and the gateway is configured with the ccm-manager config and the ccm-manager config server commands, the gateway can download its XML configuration file from the TFTP server.

The gateway then parses the XML file, converts the information to appropriate Cisco IOS configuration commands, and configures itself for MGCP operation.

Figure 10-8 MGCP E1 Endpoint Configuration

Figure 10-8 MGCP E1 Endpoint Configuration

Figure 10-9 MGCP E1 Endpoint Configuration (continued)

Verify product-specific configuration and change if required

Click for help about configuration parameters

Verify product-specific configuration and change if required

Click for help about configuration parameters

The gateway registers with CUCM using the MGCP protocol.

After a successful configuration download, the MGCP gateway saves the running configuration to NVRAM, which updates the startup configuration. Any manually added configuration parameters are also saved to NVRAM if they were not previously saved. Manually added configuration parameters are updates to the configuration that were made using the command-line interface (CLI).

In Example 10-1, there is one CUCM TFTP server with an IP address of 10.1.1.1. There is a Cisco IOS MGCP gateway with a connection to the PSTN using an E1 interface (port 0/3/0). The gateway and its E1 PRI endpoint have been added to CUCM. At the gateway, the commands ccm-manager config server 10.1.1.1 and ccm-manager config server have been entered. No MGCP configuration commands have been manually entered. The MGCP configuration is automatically downloaded and applied by the Configuration Server feature.

After the gateway downloads the cnf.xml configuration file from the CUCM TFTP server, the following MGCP commands are added to the router.

Example 10-1 Configuring MGCP Gateway Registration

controller E1 0/3/0

framing crc4

linecode hdb3

pri-group timeslots 1-31 service mgcp i

interface Serial0/3/0:15

isdn switch-type primary-4ess

isdn incoming-voice voice

isdn bind-l3 ccm-manager i

ccm-manager mgcp

ccm-manager music-on-hold i

mgcp

mgcp call-agent 10.1.1.1 2427 service-type mgcp version

5.1

mgcp rtp unreachable timeout 1000 action notify

mgcp modem passthrough voip mode nse

mgcp package-capability rtp-package

mgcp package-capability sst-package

mgcp package-capability pre-package

no mgcp package-capability res-package

no mgcp package-capability fxr-package

no mgcp timer receive-rtcp

mgcp sdp simple

mgcp rtp payload-type g726r16 static

MGCP Gateway: Registration Verification

MGCP gateways register with CUCM in a manner similar to SCCP phones. Each endpoint in the CUCM MGCP gateway configuration can be verified to obtain the registration status. Similar registration verification information is available from the gateway router via Cisco IOS commands. The show ccm-manager command in Example 10-2 shows that the MGCP gateway has a CUCM group that includes only one CUCM and that the gateway is currently registered. There are some useful statistics, too.

Example 10-2 Verifying MGCP Gateway Registration

Router# show ccm-manager

MGCP Domain Name: Router

Priority Status Host

Primary Registered 10.16.240.124

First Backup None

Second Backup None

Current active Call Manager: 10.16.240.124

Backhaul/Redundant link port: 2428

Failover Interval: 30 seconds

Keepalive Interval: 15 seconds

Last keepalive sent: 00:45:31 (elapsed time: 00

:00:04)

Last MGCP traffic time: 00:45:31 (elapsed time:

00:00:04)

Last failover time: None

Switchback mode: Graceful

MGCP Fallback mode: Not Selected

Last MGCP Fallback start time: 00:00:00

Last MGCP Fallback end time: 00:00:00

PRI Backhaul Link info

Link Protocol: TCP

Remote Port Number: 2428

Remote IP Address: 10.16.240.124

Current Link State: OPEN

Statistics:

Packets recvd: 32

Recv failures: 0

Packets xmitted: 32

Xmit failures: 0

PRI Ports being backhauled: Slot 1, port 0

!

Configuration Auto-Download Information

No configurations downloaded

Current state: Automatic Configuration Download

feature is disabled Configuration Error

History:

FAX mode: cisco

Although the MGCP gateway is registered, the endpoint in question might not be registered. The show mgcp endpoints command is useful to see which endpoints have registered. The output in Example 10-3 indicates that the T1 in slot 1/0 has registered all 24 channels as a PRI.

Example 10-3 Verifying Endpoint Registration

Router# show mgcp endpoints

Interface T1 1/0 !

ENDPOINT-NAME V-PORT SIG-TYPE ADMIN

Router# show mgcp endpoints

Interface T1 1/0 !

ENDPOINT-NAME V-PORT SIG-TYPE ADMIN

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