Cisco IOS Software Releases 12.2 Special and Early Deployments

Table of Contents

MGCP 1.0 Including NCS 1.0 and TGCP 1.0 Profiles

Feature History

The MGCP 1.0 Including NCS 1.0 and TGCP 1.0 Profiles feature module describes the features of the Media Gateway Control Protocol (MGCP) 1.0, the PacketCable^TM Network-based Call Signaling (NCS) 1.0, and the PacketCable^TM Trunking Gateway Control Protocol (TGCP) 1.0 on Cisco IOS media gateways, and contains these sections:

Feature Overview

This feature implements the following MGCP protocols on the supported Cisco media gateways:

Table 1 shows the platform-to-feature support in this release of Cisco IOS software.

Table 1   Feature Support by Platform

Feature Definition

Media Gateway Control Protocol (MGCP)1.0 is a protocol for the control of Voice over IP (VoIP) calls by external call-control elements known as media gateway controllers (MGCs) or call agents (CAs). It is described in the informational RFC2705, published by the Internet Society.

PacketCable is an industry-wide initiative to develop interoperability standards for multimedia services over cable facilities using packet technology. PacketCable developed the NCS and TGCP protocols, which contain extensions and modifications to MGCP while preserving basic MGCP architecture and constructs. NCS is designed for use with analog, single-line user equipment on residential gateways, while TGCP is intended for use in VoIP-to-PSTN trunking gateways in a cable environment.

MGCP Model

MGCP bases its call control and intelligence in centralized call agents, also called media gateway controllers. The call agents issue commands to simple, low-cost endpoints, which are housed in media gateways (MGs), and they also receive event reports from the gateways. MGCP messages between call agents and media gateways are sent over IP/UDP.

The MGCP 1.0 Including NCS 1.0 and TGCP 1.0 Profiles feature provides protocols for residential gateways (RGWs) and trunking gateways (TGWs), which sit at the border of the packet network to provide an interface between traditional, circuit-based voice services and the packet network. Residential gateways offer a small number of analog line interfaces, while trunking gateways generally manage a large number of digital trunk circuits.

Two basic MGCP constructs are endpoints and connections. An endpoint is a source or sink for call data (RTP/IP) that is flowing through the gateway. A common type of endpoint is found at the physical interface between the POTS or PSTN service and the gateway; this type of endpoint might be an analog voice port or a digital DS0 group. There are other types of endpoints as well, and some are logical rather than physical. An endpoint is identified by a two-part endpoint name that contains the name of the entity on which it exists (for example, an access server or router) and the local name by which it is known (for example, a port identifier).

A connection is a temporary allocation of resources that enables a call to be completed. One or more connections is necessary to complete a call. Connections have names that identify them with the call to which they belong. Connections can be one-to-one or multipoint. Calls and connections are initiated, modified, and deleted on instructions from call agents.

Call agents manage call flow through standard MGCP commands that are sent to the endpoints under their control. The commands are delivered in standard ASCII text, and may contain session descriptions transmitted in Session Description Protocol (SDP), a text-based protocol. These messages are sent over IP/UDP.

Call agents keep track of endpoint and connection status through the gateway's reporting of standard events that are detected from endpoints and connections. Call agents also direct gateways to apply certain standard signals when a POTS/PSTN connection expects them. For example, when someone picks up a telephone handset, an off-hook event is detected on an endpoint on the residential gateway to which the telephone is connected. The gateway reports the event to a call agent, which orders the gateway to apply the dial-tone signal to the endpoint reporting the off-hook event. The person picking up the handset hears dial tone.

Related events and signals are grouped into standard packages that apply to particular types of endpoints. For instance, the off-hook event is found in the line package, which is associated with analog-line endpoints, which in turn are associated with residential gateways. Standard events, signals, and packages are defined in the NCS, TGCP, and MGCP standards and RFCs listed in the "Supported Standards, MIBs, and RFCs" section.

Figure 1 shows a hypothetical MGCP network with both residential and trunking gateways. The residential gateway has telephone sets connected to the gateway's FXS voice ports. MGCP or NCS over IP/UDP is used for call control and reporting to the call agent, while Real-time Transmission Protocol (RTP) is used to transmit the actual voice data.

Figure 1 also shows two trunking gateways with T1 (or E1) connections to the PSTN. Incoming time-division multiplexing (TDM) data is sent through the gateway into the packet network using RTP. MGCP or TGCP over IP/UDP is used for call control and reporting to the call agent. Signaling System 7 (SS7) data travels a different route, however, bypassing the trunking gateway entirely in favor of a specialized signaling gateway, where the signaling data is transformed to ISUP/IP format and relayed to the call agent. Communication between two signaling gateways in the same packet network can be done with ISUP/IP, H.323, or Session Initiation Protocol (SIP).

Benefits

Restrictions

NCS 1.0 features are not supported on the Cisco AS5300, Cisco AS5350 or Cisco AS5400.

Related Features and Technologies

Voice over IP (VoIP)

Related Documents

Supported Platforms

This feature is supported on the following platforms:

Supported Standards, MIBs, and RFCs

Standards

MIBs

For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

RFCs

Prerequisites

Complete the following tasks before configuring this feature:

For more information on IP routing, refer to the Cisco IOS IP Configuration Guide,  Release 12.2.

For more information on configuring voice ports, refer to the Cisco IOS Voice, Video, and Fax Configuration Guide ,  Release 12.2.

For more information on configuring Voice over IP, refer to the Cisco IOS Voice, Video, and Fax Configuration Guide ,  Release 12.2.

For more information on setting up call agents, refer to the documentation that accompanies the call agents used in your network configuration.

For more information, see the documentation for the cable product as listed in the "Related Documents" section.

Configuration Tasks

The set of tasks in the list below configures the MGCP 1.0 Including NCS 1.0 and TGCP 1.0 Profiles feature on a media gateway. The first task names the voice ports or DS1 groups that are serving as MGCP endpoints. This task also associates them with an MGCP service type or application. The second task starts the MGCP daemon.

The last two tasks allow you to configure MGCP parameters to meet your requirements. MGCP parameters fall into one of two categories: global or profile-related. When you configure a global MGCP parameter value, it applies to all the MGCP endpoints on the gateway. When you configure a profile-related MGCP parameter value, it applies only to the endpoints associated with the MGCP profile that you are configuring at that moment (an MGCP profile is a user-defined subset of all the MGCP endpoints on the gateway). There is also a default MGCP profile by which you can configure profile-related parameters when endpoints do not belong to user-defined MGCP profiles. The different commands that configure global and profile-related MGCP parameters are listed in Table 2.

See the following sections for configuration tasks for the MGCP 1.0 Including NCS 1.0 and TGCP 1.0 Profiles feature. Each task in the list indicates if the task is optional or required.

Identifying MGCP Endpoints

This task is required. Voice ports or DS0 groups that are acting as MGCP endpoints must be identified as MGCP endpoints on the gateway. The commands to identify MGCP endpoints depend on the type of endpoint that you are configuring. Use the commands in Table 3 for ISUP signaling trunks, Table 4 for FGD-OS signaling trunks, Table 5 for digital CAS signaling trunks, and Table 6 for analog CAS and POTS lines.

To identify an MGCP endpoint, complete the steps in the appropriate table, beginning in global configuration mode:

Starting the MGCP Daemon

This task is required. To start the MGCP daemon, complete this step, beginning in global configuration mode:

Configuring Global MGCP Parameters

This optional task configures global MGCP parameters on the gateway so that you can set these values to conform to the requirements of the call agent, trunks, or lines that are being used with this gateway. The global parameter values that you configure affect all the MGCP endpoints that you have identified on this gateway.

In addition to global MGCP parameters, there are also other MGCP parameters that apply to MGCP profiles on the gateway. Table 2 lists the different commands that configure global and profile-related MGCP parameters. For configuration of profile-related parameters, see the "Configuring an MGCP Profile and Profile-Related MGCP Parameters" section.

Note   The only parameter that is common to both profile and global configurations is call agent, which is configured with the call-agent command for MGCP profile configuration and with the mgcp call-agent command for the global configuration. These commands are mutually exclusive; if one of these commands is configured for an endpoint, you are blocked from configuring the other. For example, if the MGCP profile call-agent command is configured on an endpoint, then you will not be allowed to configure the global mgcp call-agent command. This applies the other way round as well.

To configure global MGCP parameters, complete these steps as needed, beginning in global configuration mode:

	Command	Purpose
Step 1	Router(config)# mgcp call-agent {dns-name | ip-address} [port] [service-type type] [version protocol-version]	Configures the call agent (media gateway controller) DNS host name or IP address, UDP port number, service type, and protocol version. Note    You can define a call agent globally with the mgcp call-agent command, or locally for each MGCP profile with the call-agent command, but not both. Whichever command you configure first blocks configuration of the other.
Step 2	Router(config)# mgcp sdp simple	Specifies that a subset of the SDP fields should be used.
Step 3	Router(config)# mgcp sdp xpc-codec	Enables codec negotiation in the SDP.
Step 4	Router(config)# mgcp codec type [packetization-period value]	Selects the default codec type and its optional packetization period value.
Step 5	Router(config)# no mgcp timer receive-rtcp	Turns off the RTP RTCP transmission interval at the gateway.
Step 6	Router(config)# no mgcp piggyback message	Disables piggyback messages.
Step 7	Router(config)# mgcp endpoint offset	Increments the voice-port or DS0-group portion of the endpoint name for NCS 1.0.
Step 8	Router(config)# mgcp persistent {offhook | onhook | hookflash}	Enables call-agent notification of the specified type of event.
Step 9	Router(config)# mgcp request timeout {timeout-value | max maxtimeout-value}	Specifies how long the gateway waits for a call-agent response to a request before retransmitting the request.
Step 10	Router(config)# mgcp dtmf-relay voip codec {all | low-bit-rate} mode {cisco | nse | out-of-band}	Ensures accurate forwarding of digits with a compressed codec.
Step 11	Router(config)# mgcp max-waiting-delay value	Specifies the number of milliseconds to wait after a restart (default of 3000) before connecting with the call agent. If used, these values should be staggered among gateways to avoid having large numbers of gateways connecting with the call agent at the same time after a mass restart.
Step 12	Router(config)# mgcp restart-delay value	Sets the delay value sent in the RSIP (RestartInProgress) graceful teardown.
Step 13	Router(config)# mgcp vad	Enables voice activity detection (VAD) as a default for MGCP calls.
Step 14	Router(config)# mgcp ip-tos {high-reliability | high-throughput | low-cost | low-delay | precedence value}	Enables the IP Type of Services (TOS) for MGCP-controlled connections and specifies the value for the IP precedence bit (the default IP precedence is 3).
Step 15	Router(config)# mgcp quality-threshold {hwm-jitter-buffer value | hwm-latency value | hwm-packet-loss value | lwm-jitter-buffer value | lwm-latency value | lwm-packet-loss value}	Sets the jitter buffer size threshold, latency threshold, and packet-loss threshold parameters.
Step 16	Router(config)# mgcp playout {adaptive init-value min-value max-value | fixed init-value}	Configures the jitter buffer packet size in milliseconds for MGCP calls, using either an adaptive range or a fixed value. Each value ranges from 4 to 250 milliseconds. The default is adaptive 60 4 200.
Step 17	Router(config)# mgcp package-capability [package-type]	Specifies an MGCP package to be supported on this gateway. Configure one package at a time and repeat this command to configure support for more than one package. For residential gateways, the choices are dtmf-package, gm-package, line-package, and rtp-package. The default is line-package. For trunking gateways, the choices are as-package, dtmf-package, gm-package, mf-package, nas-package, rtp-package, script-package, and trunk-package. The default is trunk-package.
Step 18	Router(config)# mgcp default package [package-type]	Defines the package to be used as the default when no package is named with an event. For residential gateways, the choices are dtmf-package, gm-package, line-package, and rtp-package. The default is line-package. For trunking gateways, the choices are as-package, dt-package, dtmf-package, gm-package, mf-package, mo-package, ms-package, nas-package, rtp-package, script-package, and trunk-package. The default is trunk-package.

Configuring an MGCP Profile and Profile-Related MGCP Parameters

This optional task creates a named, user-defined MGCP profile that consists of a subset of all the MGCP endpoints on this gateway. More than one MGCP profile can be configured on a gateway. Each MGCP profile is associated with a call agent and one or more endpoints. When multiple MGCP profiles are configured, endpoints on a single media gateway can be controlled by different call agents. When each endpoint comes on line, an RSIP (RestartInProgress) message notifies the appropriate call agent of the endpoint's presence.

Note   When partitioning a gateway for multiple call-agent control, the call agents must be coordinated so that there are no overlapping transaction identification numbers.

In addition, this task allows you to configure profile-related MGCP parameters to conform to the requirements of the call agent, trunks, or lines that are being used with the profile's endpoints. These parameters are called profile-related MGCP parameters because they are associated with a particular MGCP profile, or subset of endpoints, and they are configured in MGCP profile configuration mode. Other parameters are considered global MGCP parameters; when they are configured, they apply to all the endpoints on a gateway. Table 2 lists commands that configure global and profile-related MGCP parameters. Global MGCP parameters are discussed in the "Configuring Global MGCP Parameters" section.

The parameters for an MGCP profile are configured in a special MGCP profile configuration mode that you enter with the mgcp profile command. One or more endpoints are associated with the profile by using the voice-port command in MGCP profile configuration mode.

Note   The only parameter that can be configured in both profile configuration mode and in global configuration mode is call agent, which is configured with the call-agent command for MGCP profiles, and with the mgcp call-agent command for global configurations. These commands are mutually exclusive; if one of these commands is configured, you are blocked from configuring the other. For example, if the MGCP profile call-agent command is configured for an MGCP profile, then you are not allowed to configure the global mgcp call-agent command. This applies the other way round as well.

You do not have to define MGCP profiles to configure profile-related parameters. For endpoints that are not associated with a user-defined MGCP profile, the values for profile-related parameters are provided by a default profile. The default profile is configured in the same way that a user-defined MGCP profile is configured, except that the keyword default is used in place of a profile name in the mgcp profile command. The default profile has no association with voice ports or a call agent (the call agent for these endpoints is defined by the global mgcp call-agent command).

In the example below, two MGCP profiles are defined: MAX1 and MAX2. Each profile is associated with a different call agent and a different voice port. The MAX1 profile is configured with a value of 3 for the max1 retries parameter and 5 for max2 retries. The MAX2 profile uses the values in the default profile for those parameters. In the MAX2 profile, the MT package is configured as a persistent package. The max1 retries parameter for the default profile is configured with a value of 2. The max2 retries parameter is not configured, so the value used is the default value, which is 7. The MAX2 profile has a value of 2 for the max1 retries parameter and 7 for max2 retries.

To configure parameters for a user-defined MGCP profile or for the default profile, follow these steps as appropriate, beginning in global configuration mode:

	Command	Purpose
Step 1	Router(config)# mgcp profile {profile-name | default}	Initiates MGCP profile mode to create and configure a named MGCP profile associated with one or more endpoints, or to configure the default profile.
Step 2	Router(config-mgcp-profile)# description {text}	Provides a description to be associated with the profile.
Step 3	Router(config-mgcp-profile)# call-agent {dns-name | ip-address} [port] [service-type type] [version protocol-version]	Defines the call agent's DNS name or IP address, UDP port number, service type, and protocol version. (Not used when configuring the default profile.) Note    You can define a call agent globally with the mgcp call-agent command, or locally for each MGCP profile with the call-agent command, but not both. Whichever command you configure first blocks configuration of the other.
Step 4	Router(config-mgcp-profile)# voice-port port-number	Provides the voice port number or DS0 group number for the endpoint to be associated with this MGCP profile. Repeat this command to add more than one endpoint to the profile. (Not used when configuring the default profile.)
Step 5	Router(config-mgcp-profile)# default {command}	Restores the command parameter to its default value.
Step 6	Router(config-mgcp-profile)# package persistent package-name	Configures the package type used when reporting persistent events for an MF CAS endpoint type.
Step 7	Router(config-mgcp-profile)# timeout tsmax tsmax-value	Configures the maximum timeout value after which MGCP messages are removed from the retransmission queue.
Step 8	Router(config-mgcp-profile)# timeout tdinit tdinit-value	Configures the initial waiting delay value (Tdinit) used as the timer for the disconnect procedure.
Step 9	Router(config-mgcp-profile)# timeout tcrit tcrit-value	Configures the critical timeout value (Tcritical) for the interdigit timer used in digit map matching.
Step 10	Router(config-mgcp-profile)# timeout tpar tpar-value	Configures the partial timeout value (Tpartial) for the interdigit timer used in digit map matching.
Step 11	Router(config-mgcp-profile)# timeout thist thist-value	Configures the packet storage timeout value.
Step 12	Router(config-mgcp-profile)# timeout tone mwi mwitone-value	Configures the message waiting indicator timeout value.
Step 13	Router(config-mgcp-profile)# timeout tone ringback ringbacktone-value	Configures the ringback tone timeout value.
Step 14	Router(config-mgcp-profile)# timeout tone ringback connection connectiontone-value	Configures the timeout value for ringback tone on connection.
Step 15	Router(config-mgcp-profile)# timeout tone network congestion congestiontone-value	Configures the network congestion tone timeout value.
Step 16	Router(config-mgcp-profile)# timeout tone busy busytone-value	Configures the busy tone timeout value.
Step 17	Router(config-mgcp-profile)# timeout tone dial dialtone-value	Configures the dial tone timeout value.
Step 18	Router(config-mgcp-profile)# timeout tone dial stutter stuttertone-value	Configures the stutter dial tone timeout value.
Step 19	Router(config-mgcp-profile)# timeout tone ringing ringingtone-value	Configures the ringing tone timeout value.
Step 20	Router(config-mgcp-profile)# timeout tone ringing distinctive distinctivetone-value	Configures the distinctive ringing tone timeout value.
Step 21	Router(config-mgcp-profile)# timeout tone reorder reordertone-value	Configures the reorder tone timeout value.
Step 22	Router(config-mgcp-profile)# timeout tone cot1 continuity1tone-value	Configures the continuity1 tone timeout value.
Step 23	Router(config-mgcp-profile)# timeout tone cot2 continuity2tone-value	Configures the continuity2 tone timeout value.
Step 24	Router(config-mgcp-profile)# max1 lookup	Enables the DNS lookup procedure after the suspicion threshold is reached.
Step 25	Router(config-mgcp-profile)# max1 retries value	Sets the suspicion threshold value.
Step 26	Router(config-mgcp-profile)# max2 lookup	Enables the DNS lookup procedure after the disconnect threshold is reached.
Step 27	Router(config-mgcp-profile)# max2 retries value	Sets the disconnect threshold value.
Step 28	Router(config-mgcp-profile)# exit	Exits MGCP profile configuration mode.

Verifying the Configuration

Use these commands to verify configuration settings for all platforms and protocols:

Troubleshooting Tips

The following suggestions will help with troubleshooting:

Configuration Examples

This section provides the following configuration examples:

Configuring the Cisco uBR924 Using the RF Interface

This example sets up a Cisco uBR924 as an MGCP residential gateway. The call agent is specified to the cable router (uBR924 or CVA122) by a DHCP offer on a cable R/F network. On completion of the DHCP offer, the call agent is set in the MGCP profile on the cable modem. This setting is displayed with the show mgcp profile command. The router does not show the call agent in the CLI.

Configuring the Cisco uBR924 Using the Ethernet0 Interface

This example sets up a Cisco uBR924 as a residential gateway.

Configuring the Cisco CVA122 Using the RF Interface

The call agent is specified to the cable router (uBR924 or CVA122) by a DHCP offer on a cable R/F network. On completion of the DHCP offer, the call agent is set in the MGCP profile on the cable modem. This setting is displayed with the show mgcp profile command. The router does not show the call agent in the CLI.

Configuring the Cisco AS5400

This example sets up a Cisco AS5400 as an MGCP trunking gateway.

Command Reference

This section documents new and modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.2 command reference publications or in the MGCP documentation listed in the "Related Documents" section.

Following the alphabetical list of new and modified commands is a list of the same commands grouped by configuration mode.

Alphabetical List of Commands

Commands by Configuration Mode

Privileged Exec Mode Commands

Global Configuration Mode Commands

MGCP Profile Configuration Mode Commands

call-agent

To define the call agent for an MGCP profile, use the call-agent MGCP profile command. To return to the default values, use the no form of this command.

call-agent {dns-name | ip-address} [port] [service-type type] [version protocol-version]

no call-agent

Syntax Description

Defaults

The default call-agent UDP port is 2727 for MGCP 1.0, NCS 1.0, and TGCP 1.0.

The default call-agent UDP port is 2427 for MGCP 0.1 and SGCP.

The default service type and version is mgcp 0.1.

Command Modes

MGCP profile configuration

Command History

Usage Guidelines

Call-agent configuration for an MGCP profile (with this command) and global call-agent configuration (with the mgcp call-agent command) are mutually exclusive; the first to be configured on an endpoint blocks configuration of the other on the same endpoint.

Identifying call agents by DNS name rather than IP address in the call-agent command provides call-agent redundancy, because a DNS name can have more than one IP address associated with it. If a call agent is identified by DNS name and a message from the gateway fails to reach the call agent, the max1 lookup and max2 lookup commands enable a search from the DNS lookup table for a backup call agent at a different IP address.

The port argument configures the call agent port number (the UDP port over which the gateway sends messages to the call agent). The reverse, or the gateway port number (the UDP port over which the gateway receives messages from the call agent) is configured by specifying a port number in the mgcp command.

The service-type mgcp supports the RestartInProgress (RSIP) error messages sent by the gateway if mgcp sgcp restart notify is enabled. The service-type sgcp ignores the RSIP messages.

Examples

The following example defines a call agent for the MGCP profile named tgcp_trunk:

Related Commands

debug mgcp

To enable debug traces for MGCP errors, events, media, packets, and parser, use the debug mgcp privileged EXEC command. To disable debugging output, use the no form of this command.

debug mgcp [all | errors [endpoint endpoint-name] | events {endpoint endpoint-name} | media {endpoint endpoint-name} | packets [endpoint endpoint-name | input-hex] | parser]

no debug mgcp [all | errors | events | media | packets | parser]

Syntax Description

Defaults

Debugging for DRiP packets is not enabled.

Command Modes

EXEC

Command History

Usage Guidelines

There is always a performance penalty when using debug commands.

Examples

Following are sample outputs for the debug mgcp packets, debug mgcp events, and debug mgcp parser commands. The debug mgcp all command would show a compilation of all this output.

The following example illustrates the output for the debug mgcp events command:

The following example illustrates the output for the debug mgcp packets command:

The following example illustrates the output for the debug mgcp parser command:

default (MGCP profile)

To configure an MGCP profile parameter to its default value, use the default MGCP profile command or use the no form of the command for that profile parameter.

default command

Syntax Description

Command Modes

MGCP profile

Defaults

There are no defaults for this command.

Command History

Usage Guidelines

The default (MGCP profile) command instructs the MGCP profile to use the default value of the specified command whenever the profile is called. This has the same effect as using the no form of the specified command, but the default command clearly specifies which commands are using their default values.

To use the default values for more than one command, enter each command on a separate line.

Examples

The following example shows an MGCP profile that uses the default values for three commands:

Related Commands

description (MGCP profile)

To provide a description of the MGCP profile that is being defined, use the description MGCP profile command.

description text

Syntax Description

Command Modes

MGCP profile

Defaults

This command has no default value.

Command History

Usage Guidelines

The description is printed in the output for the show mgcp profile command and others.

Examples

The following example shows a description for an MGCP profile:

Related Commands

max1 lookup

To enable DNS lookup for a new call-agent address when the suspicion threshold value is reached, use the max1 lookup MGCP profile command. To disable lookup, use the no form of the command.

max1 lookup

no max1 lookup

Syntax Description

There are no keywords or arguments for this command.

Defaults

Lookup is enabled.

Command Modes

MGCP profile

Command History

Usage Guidelines

Call-agent redundancy can be provided when call agents are identified by DNS name rather than IP address in the call-agent command, because each DNS name can have more than one IP address associated with it.

When the active call agent does not respond to a message from the media gateway, the gateway becomes suspicious that the call agent is out of service. The gateway retransmits the message to the call agent for the number of times specified in the max1 retries command; this is known as the suspicion threshold. If there is no response and the max1 lookup command is enabled, the gateway examines the DNS lookup table to find the IP address of another call agent. If a second call agent is listed, the gateway retries the message to the second call agent until a response is received or the number of retries specified in the max1 retries command is reached. This process is repeated for each IP address in the DNS table until the final address is reached. For the final address, the number of retries is specified by the max2 retries command; this is known as the disconnect threshold. If the number of retries specified in the max2 retries command is reached and there is still no response and the max2 lookup command is enabled, the gateway performs one final DNS lookup. If any new IP addresses have been added, the gateway starts the retransmission process again. Otherwise, the gateway places the endpoint in a disconnected state.

Examples

The following example shows how to enable the DNS lookup procedure and set the suspicion retransmission counter value to 7:

Related Commands

max1 retries

To set the MGCP suspicion threshold value, use the max1 retries MGCP profile command. To return the number of retries to the default, use the no form of the command.

max1 retries number

no max1 retries

Syntax Description

Defaults

5

Command Modes

MGCP profile

Command History

Usage Guidelines

Call-agent redundancy can be provided when call agents are identified by DNS name rather than by IP address in the call-agent command, because each DNS name can have more than one IP address associated with it.

When the active call agent does not respond to a message from the media gateway, the gateway becomes suspicious that the call agent is out of service. The gateway retransmits the message to the call agent for the number of times specified in the max1 retries command; this is known as the suspicion threshold. If there is no response and the max1 lookup command is enabled, the gateway examines the DNS lookup table to find the IP address of another call agent. If a second call agent is listed, the gateway retries the message to the second call agent until a response is received or the number of retries specified in the max1 retries command is reached. This process is repeated for each IP address in the DNS table until the final address is reached. For the final address, the number of retries is specified by the max2 retries command; this is known as the disconnect threshold. If the number of retries specified in the max2 retries command is reached and there is still no response and the max2 lookup command is enabled, the gateway performs one final DNS lookup. If any new IP addresses have been added, the gateway starts the retransmission process again. Otherwise, the gateway places the endpoint in a disconnected state.

Examples

The following example shows how to enable the DNS lookup procedure and set the suspicion retransmission counter value to 7:

Related Commands

max2 lookup

To enable DNS lookup for a new call-agent address after the disconnect threshold timeout value is reached, use the max2 lookup MGCP profile command. To disable DNS lookup, use the no form of the command.

max2 lookup

no max2 lookup

Syntax Description

There are no keywords or arguments for this command.

Defaults

Lookup is enabled.

Command Modes

MGCP profile

Command History

Usage Guidelines

Call-agent redundancy can be provided when call agents are identified by DNS name rather than IP address in the call-agent command, because each DNS name can have more than one IP address associated with it.

When the active call agent does not respond to a message from the media gateway, the gateway becomes suspicious that the call agent is out of service. The gateway retransmits the message to the call agent for the number of times specified in the max1 retries command; this is known as the suspicion threshold. If there is no response and the max1 lookup command is enabled, the gateway examines the DNS lookup table to find the IP address of another call agent. If a second call agent is listed, the gateway retries the message to the second call agent until a response is received or the number of retries specified in the max1 retries command is reached. This process is repeated for each IP address in the DNS table until the final address is reached. For the final address, the number of retries is specified by the max2 retries command; this is known as the disconnect threshold. If the number of retries specified in the max2 retries command is reached and there is still no response and the max2 lookup command is enabled, the gateway performs one final DNS lookup. If any new IP addresses have been added, the gateway starts the retransmission process again. Otherwise, the gateway places the endpoint in a disconnected state.

Examples

The following example shows how to enable the DNS lookup procedure and set the disconnect retransmission counter value to 9:

Related Commands

max2 retries

To set the MGCP disconnect threshold value, use the max2 retries MGCP profile command. To disable lookup or return the number of retries to the default, use the no form of the command.

max2 retries number

no max2 retries

Syntax Description

Defaults

7

Command Modes

MGCP profile

Command History

Usage Guidelines

Call-agent redundancy can be provided when call agents are identified by DNS name rather than IP address in the call-agent command, because each DNS name can have more than one IP address associated with it.

When the active call agent does not respond to a message from the media gateway, the gateway becomes suspicious that the call agent is out of service. The gateway retransmits the message to the call agent for the number of times specified in the max1 retries command; this is known as the suspicion threshold. If there is no response and the max1 lookup command is enabled, the gateway examines the DNS lookup table to find the IP address of another call agent. If a second call agent is listed, the gateway retries the message to the second call agent until a response is received or the number of retries specified in the max1 retries command is reached. This process is repeated for each IP address in the DNS table until the final address is reached. For the final address, the number of retries is specified by the max2 retries command; this is known as the disconnect threshold. If the number of retries specified in the max2 retries command is reached and there is still no response and the max2 lookup command is enabled, the gateway performs one final DNS lookup. If any new IP addresses have been added, the gateway starts the retransmission process again. Otherwise, the gateway places the endpoint in a disconnected state.

Examples

The following example shows how to set the disconnect retransmission counter value to 9:

Related Commands

mgcp call-agent

To configure the address and protocol of the call agent (media gateway controller) for MGCP endpoints on a media gateway, use the mgcp call-agent global configuration command. To return to default values, use the no form of this command.

mgcp call-agent {dns-name | ip-address} [port] [service-type type] [version protocol-version]

no mgcp call-agent

Syntax Description

Defaults

The default call-agent UDP port is 2727 for MGCP 1.0, NCS 1.0, and TGCP 1.0.

The default call-agent UDP port is 2427 for MGCP 0.1 and SGCP.

The default service type and version is mgcp 0.1.

Command Modes

Global configuration

Command History

Usage Guidelines

Global call-agent configuration (with this command) and call-agent configuration for an MGCP profile (with the MGCP profile call-agent command) are mutually exclusive; the first to be configured on an endpoint blocks configuration of the other on the same endpoint.

Identifying call agents by DNS name rather than IP address in the call-agent command provides call-agent redundancy, because a DNS name can have more than one IP address associated with it. If a call agent is identified by DNS name and a message from the gateway fails to reach the call agent, the max1 lookup and max2 lookup commands enable a search from the DNS lookup table for a backup call agent at a different IP address.

The port argument configures the call-agent port number (the UDP port over which the gateway sends messages to the call agent). The reverse (the gateway port number, or the UDP port over which the gateway receives messages from the call agent) is configured by specifying a port number in the mgcp command. The default gateway port number is always 2427.

The service-type mgcp supports the RestartInProgress (RSIP) error messages sent by the gateway if mgcp sgcp restart notify is enabled. The service-type sgcp ignores the RSIP messages.

Examples

The following examples demonstrate various forms of the command:

Related Commands

mgcp endpoint offset

When using the NCS 1.0 profile of MGCP, enable incrementing of the POTS or DS0 portion of an endpoint name with the mgcp endpoint offset global configuration command. To return the endpoint name to the default, use the no form of this command.

mgcp endpoint offset

no mgcp endpoint offset

Syntax Description

This command has no keywords or arguments.

Defaults

Disabled

Command Modes

Global configuration

Command History

Usage Guidelines

This command is used with NCS 1.0 to increment the POTS or DS0 portion of an endpoint name by 1, to minimize potential interoperability problems with call agents (media gateway controllers).

NCS 1.0 mandates that the port number of an endpoint be based on 1, and port numbering on some gateway platforms is based on 0.

When this command is configured, it offsets all endpoint names on the gateway. For example, an endpoint with a port number of aaln/0 is offset to aaln/1, and a DS0 group number of 0/0:0 is offset to 0/0:1.

Examples

The following example shows the port number portion of an endpoint name being incremented:

Related Commands

mgcp persistent

To configure the sending of persistent events from the gateway to the call agent, use the mgcp persistent global configuration command. To return to the default values, use the no form of this command.

mgcp persistent {hookflash | offhook | onhook}

no mgcp persistent {hookflash | offhook | onhook}

Syntax Description

Command Modes

Global configuration

Defaults

The offhook option is enabled for persistence.

The onhook option is disabled for persistence.

The hookflash detection option is disabled for persistence.

Command History

Usage Guidelines

Persistent events are those events that, once they are detected, are defined as reportable to the call agent whether or not the call agent has explicitly requested to be notified of their occurrence; that is, even if they are not included in the list of RequestedEvents that the gateway is asked to detect and report. Such events include, for example, fax tones, continuity tones, or on-hook transition; each event has an associated action for the gateway to take.

Use the mgcp persistent command for each type of persistent event that should override the default behavior.

Examples

The following example shows how to configure the gateway to send persistent onhook events to the call agent:

Related Commands

mgcp piggyback message

To enable piggyback messages, use the mgcp piggyback message global configuration command. To disable piggyback messages, use the no form of this command.

mgcp piggyback message

no mgcp piggyback message

Syntax Description

This command has no keywords or arguments.

Defaults

Piggyback messages are enabled.

Command Modes

Global configuration

Command History

Usage Guidelines

Use this command to disable piggyback messages for MGCP 1.0, NCS, and TGCP when a network gateway cannot handle piggyback messages. Piggyback messaging is not available to SGCP and MGCP 0.1.

The term piggyback message refers to a situation in which a gateway or a call agent sends more than one MGCP message in the same UDP packets. The recipient processes the messages individually, in the order received. However, if a message must be retransmitted, the entire datagram is resent. The recipient must be capable of sorting out the messages and keeping track of which messages have been handled or acknowledged.

Piggybacking is used during retransmission of a message to send previously unacknowledged messages to the call agent. This maintains the order of events the call agent receives, and makes sure that RSIP (RestartInProgress) messages are always received first by a call agent.

Examples

The following example illustrates how to disable piggyback messages:

Related Commands

mgcp profile

To create and configure an MGCP profile to be associated with one or more MGCP endpoints or to configure the default MGCP profile, use the mgcp profile command in global configuration mode. To delete the profile, use the no form of this command.

mgcp profile {profile-name | default}

no mgcp profile {profile-name | default}

Syntax Description

Defaults

This command does not have a default value.

Command Modes

Global configuration

Command History

Usage Guidelines

An MGCP profile is a subset of endpoints on a media gateway. More than one MGCP profile can be configured on a gateway at the same time. The voice-port command in MGCP profile configuration mode associates endpoints with the profile.

There are two types of MGCP parameters: global and profile-related. The parameters that are configured in MGCP profile configuration mode are the profile-related parameters. However, endpoints do not need to belong to an MGCP profile. When endpoints are not associated with any MGCP profile, values for the profile-related MGCP parameters are provided by a default profile. Although all of the parameters for the default profile have default values, they also can be configured in the same way that an MGCP profile is configured, by simply using the keyword default instead of a profile name. The main difference between a default profile and a user-defined profile is that there is no voice-port or call-agent association in the default profile, but they are required in user-defined profiles. When configuring the default profile, do not configure the call-agent command or the voice-port command.

The mgcp profile command initiates MGCP profile configuration mode, in which you create an MGCP profile for an endpoint or a set of endpoints on a media gateway, and you set parameters for that profile or for the default profile. The following commands are available to configure MGCP profile-related parameters:

Examples

The following example illustrates an MGCP profile definition:

Related Commands

mgcp quarantine mode

To configure event quarantine buffer handling mode, use the mgcp quarantine mode global configuration command. To restore the default value, use the no form of the command.

mgcp quarantine mode {discard [loop | step] | process [loop | step] | loop | step}

no mgcp quarantine mode {discard [loop | step] | process [loop | step] | loop | step}

Syntax Description

Defaults

discard and step

Command Modes

Global configuration

Command History

Usage Guidelines

Quarantine events are defined as events that have been detected by the gateway before the arrival of the MGCP NotificationRequest command, but that have not yet been notified to the call agent. They are held in the quarantine buffer until receipt of the MGCP NotificationRequest command, when the gateway is expected to generate either one notification (step by step), or multiple notifications (loop), in response to this request (the default is exactly one), based on the configuration of mgcp quarantine mode.

This command supports backward compatibility with SGCP implementations running under the MGCP application. SGCP does not have a way to allow the call agent to control the quarantine mode. MGCP has this functionality.

When the gateway is in the notification state, the interdigit timer (Tcrit) is not started.

When the gateway receives an unsuccessful NotificationRequest, the current RequestEventList and SignalEventList are emptied. The ObservedEventList and quarantine buffer are also emptied.

Examples

The following example turns on processing of quarantined events and sends observed events to the call agent:

The following example turns off processing of quarantined events:

The following example sends observed events to the call agent in loop mode:

Related Commands

mgcp quarantine persistent-event disable

To disable handling of persistent call events in the quarantine buffer, use the mgcp quarantine persistent-events disable global configuration command. To restore the default value, use the no form of the command.

mgcp quarantine persistent-event disable

no mgcp quarantine persistent-event disable

Syntax Description

There are no keywords or arguments for this command.

Defaults

Persistent events are held in the events buffer.

Command Modes

Global configuration

Command History

Usage Guidelines

This command enables the reporting of persistent events immediately to the call agent rather than holding the events in quarantine. Persistent events are events defined as reportable whether or not the call agent explicitly has requested to be notified of their occurrence. Quarantining means the gateway observes events but does not report them to the call agent until the call agent indicates readiness to receive notifications. By default, all events, including persistent events, are quarantined when they are detected, even when the gateway is in a notification state. When the mgcp quarantine persistent-event disable command is configured, however, persistent events are reported to the call agent immediately by an MGCP Notify command.

Examples

The following example turns off quarantine buffer handling of persistent events:

Related Commands

mgcp request retries

This command was added in Cisco IOS Release 12.1(1)T. Beginning in Cisco IOS Release 12.2(2)XA, this command no longer is supported. It has been replaced by the MGCP profile commands max1 retries and max2 retries.

mgcp request timeout

To specify how long the gateway waits for a call-agent response to a request before retransmitting the request, use the mgcp request timeout global configuration command. To restore the default value, use the no form of this command.

mgcp request timeout {timeout-value | max maxtimeout-value}

no mgcp request timeout [max]

Syntax Description

Defaults

Default for timeout-value is 500 ms.

Default for maxtimeout-value is 4,000 ms.

Command Modes

Global configuration

Command History

Usage Guidelines

The request timeout value is the value used for the initial time period that the gateway waits for a response from the call agent before retransmitting the message. The interval doubles with each retransmission. The request timeout max value sets an upper limit on the timeout interval.

Examples

The following example shows a system being set to wait 40 milliseconds for a reply to the first request before retransmitting, and limits subsequent interval maximums to 10,000 milliseconds (10 seconds):

Related Commands

mgcp sdp

To specify parameters for Session Description Protocol (SDP) operation in MGCP, use the mgcp sdp global configuration command. To return to the default value, use the no form of this command.

mgcp sdp {notation undotted | simple | xpc-codec}

no mgcp sdp {notation undotted | simple | xpc-codec}

Syntax Description

Defaults

The notation undotted option is disabled by default.

The simple option is disabled by default.

The xpc-codec option is disabled by default.

Command Modes

Global configuration

Command History

Usage Guidelines

This command allows you to configure SDP fields to meet the requirements of your call agent.

notation undotted—The codec strings G.726-16 and G.729 are dotted notation, while G726-16 and G729 are undotted. The codec notation format is selected dynamically in the following order of preference:

1. The notation used in SDP for MGCP packets from the call agent.

2. The notation used in the a: parameter of the Local connection option for MGCP packets from the call agent.

3. The notation set by the mgcp sdp notation undotted command.

simple—When simple is enabled, the gateway does not generate the following SDP fields: o (origin and session identifier), s (session name), and t (session start time and stop time). Certain call agents require this modified SDP to send data through the network.

xpc-codec—In TGCP and NCS, a new field (X-pc-codec) has been defined in the SDP for codec negotiation. To be backward compatible with non-packet-cable SDPs, the initial generation of the X-pc-codec field is suppressed by default. However, if a received SDP contains this field, the X-pc-codec is read and generated in response, to continue with the codec negotiation.

Examples

The following example shows the simple mode being configured for SDP:

Related Commands

package persistent

To configure the package type used when reporting persistent events for an MF CAS endpoint type using a specific MGCP profile, use the package persistent MGCP profile configuration command. To disable the persistent status, use the no form of the command.

package persistent package-name

no package persistent package-name

Syntax Description

Defaults

ms-package

Command Modes

MGCP profile configuration

Command History

Usage Guidelines

This command is used only with MF trunks (gateway voice ports configured with the voice-port configuration command dial-type mf). Because the same persistent event can be defined in different MGCP packages, you may need to configure the package persistent command to tell the gateway which package to use when reporting persistent events to the call agent for the endpoints in this MGCP profile. For example, a T1 may be configured as an MF trunk, but there is more than one MGCP package that applies to an MF trunk. An ans (call answer) event must be mapped to the appropriate package for call-agent notification. This command allows different T1s to be configured for different CAS protocols.

The MS package is used with certain PBX DID/DOD trunks with wink-start or ground-start protocol, as indicated in RFC3064 (MGCP CAS Packages).

The MT package is a subset of the MS package, and it is used with certain operator services on terminating MF trunks on trunking gateway endpoints, as described in PacketCable PSTN Gateway Call Signaling Protocol Specification (TGCP) PKT-SP-TGCP-D02-991028, December 1, 1999.

Examples

The following example shows event persistence being enabled for the MT package:

Related Commands

show mgcp

To display MGCP configuration information, use the show mgcp EXEC command.

show mgcp [connection | endpoint | profile [profile-name] | statistics]

Syntax Description

Defaults

None

Command Modes

EXEC

Command History

Examples

Following are examples of the command formats and outputs for: show mgcp, show mgcp connection, show mgcp statistics, show mgcp endpoint, and show mgcp profile.

The following example shows the output for VoIP connections:

The following example shows output for VoAAL2 connections:

The following example shows output for VoIP and VoAAL2 statistics:

The following example shows how endpoints are configured:

The following example displays show mgcp profile output for the default profile: