R2 and ISUP Transparency for Voice Gateways Version 2.0

Table Of Contents

R2 and ISUP Transparency for Voice Gateways Version 2.0

Feature Overview

ISUP Transparency Using GTD

R2 Transparency Using GTD

Non-standard CPC Support Using FDC and PRN

Benefits

Restrictions

Related Documents

Supported Platforms

Supported Standards, MIBs, and RFCs

Prerequisites

Configuration Tasks

Configuring R2 Transparency

Verifying R2 Transparency

Configuring ISUP Forwarding in H.225 Messages Globally

Configuring ISUP Forwarding in H.225 Messages for a Dial Peer

Verifying ISUP Forwarding in H.225 Messages

Configuring CLIP and CLIR

Verifying CLIP and CLIR

Configuration Examples

R2 Transparency Configuration Example

CLIP and CLIR Configuration Example

Command Reference

clid network-number

clid restrict

clid second-number strip

clid strip

signaling forward

Glossary

R2 and ISUP Transparency for Voice Gateways Version 2.0

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Note This document is still under development. Please revisit this site for future updates. 11/18/07

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Feature History

Release	Modification
12.2(11)T	This feature was introduced on the Cisco 3600, Cisco AS5300, Cisco AS5350, Cisco AS5400, Cisco AS5800, Cisco AS5850, and Cisco 7200 series.

This document describes enhancements to ISDN User Part (ISUP) transparency, R2-to-ISUP interworking, and R2 transparency using Generic Transparency Descriptor (GTD) objects in Cisco IOS Release 12.2(11)T. This document includes the following sections:

•Feature Overview

•Supported Platforms

•Supported Standards, MIBs, and RFCs

•Prerequisites

•Configuration Tasks

•Configuration Examples

•Command Reference

•Glossary

Feature Overview

This feature provides ISUP transparency, R2-to-ISUP interworking, and R2 transparency using GTD objects.Cisco IOS Release 12.2(11)T also provides support for Calling Line ID Presentation (CLIP) and Calling Line ID Restriction (CLIR) interworking between ISUP and H.225. This feature is part of the
Cisco SS7 Interconnect for Voice Gateways Solution Documentation.

GTD objects are generically used to represent ISUP messages, parameters, and R2 signals. These GTD objects are encapsulated into existing signaling protocols (for example, H.225), facilitating end-to-end transport. Existing implementations of ISUP transparency and R2 transparency use ISUP binary format, rather than GTD ASCII format, to transport ISUP and R2 signaling parameters. Using GTD as a transport mechanism for signaling data in Cisco IOS software provides a common format for sharing signaling data among various components in a network and for interworking various signaling protocols.

This feature adds the following additional functionality:

•Global Call Correlation ID GTD parameter generation.

•Global Call Correlation ID GTD parameter relay through the originating and terminating gateways between the Cisco PGW 2200 NI2+ and H.323 interfaces.

•Nonstandard calling party category (CPC) values support using the new Field Compatibility Information (FDC) field.

ISUP Transparency Using GTD

An ISDN message that comes into the Cisco originating gateway (OGW) from a Cisco PGW 2200 signaling controller on the NI2+ interface contains the ISUP GTD message, as shown in Figure 1.

The following is an example of the ISUP GTD call flow:

1. Signaling controller number 1 (SC1) receives ISUP messages from the public switched telephone network (PSTN) and encapsulates them into GTD format. The messages are then passed to the OGW.

2. The OGW sends the GTD messages to the terminating gateway (TGW) as H.225 nonstandard control messages and tunnelled signaling messages. Two copies of the data are actually sent; the nonstandard control is for backward compatibility with older Cisco gateways, which do not understand GTD. Tunnelled signaling is the recommended method for GTD transport.

3. The TGW restores the original GTD messages and sends them to signaling controller SC2.

4. Signaling controller number 2 (SC2) rebuilds the ISDN messages from the GTD messages.

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Note GTD can be enabled and disabled at the signaling controller.

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Figure 1 ISUP Transparency Implementation

R2 Transparency Using GTD

Channel-associated signaling (CAS) R2 signals that come into the OGW are passed transparently across the network, as shown in Figure 2.

The following is an example of the R2 GTD call flow:

1. The OGW maps R2 CAS signals into GTD format. The messages are then passed to the TGW as H.225 nonstandard control messages.

2. The TGW restores the original GTD messages and maps them back into R2 signals and tunnelled signaling messages, as described in the ISUP Transparency Using GTD section above.

Figure 2 R2 Transparency Implementation

Non-standard CPC Support Using FDC and PRN

In normal circumstances, Universal Feature Card (UFC) Generic Transparency Descriptor (GTD) parameters are used to pass the country code and the signal value end-to-end. UFC is used to provide R2-R2 transparency when the same version (or variant) of R2 signaling is being used at both ends. CPC and PRN parameters are used for R2-ISUP interworking and for unlike R2 versions (or variants) of R2-R2 interworking. The CPC GTD parameter carries the CPC value, and the Problem Report Number (PRN) parameter carries the country code. But for countries like Thailand, a direct mapping of the group II signals to GTD CPC cannot be achieved, because the Thai R2 variant has CPC values that do not map into the GTD defined list of CPC values.

To solve this problem of transporting nonstandard CPC values for certain countries, a new GTD parameter called Field Compatibility Information (FDC) is used. An FDC field is used to allow customer-specific values of known fields to be transmitted, even though the actual field is populated with a best-fit mapping. The FDC carries the actual parameter value received at the R2 interface, and the CPC carries the best-fit GTD-known value.

The algorithm at the terminating gateway has been modified to look for a CPC value in the following order:

1. The GTD parameter list is checked for a UFC.

a. If a UFC is present, the embedded country value is matched against the country value configured on the terminating R2 interface. If the country values match, the CPC value from is pulled out of the UFC is used.

b. If a UFC is not present, the parameter list is checked to see if there is an FDC.

2. If an FDC is present, the CPC is pulled out of the FDC and the country code is pulled out of the PRN parameter. Otherwise, the GTD CPC parameter is used. When there is an FDC parameter, the GTD CPC parameter itself is mapped to a value of 0x09, ordinary subscriber, which is the default best-fit value.

The following example shows mapping information for Thailand, because only Thailand requires FDC data at this time. This data is used to map the R2 CPC to the GTD FDC.

const uchar r2_grpII_to_gtd_fdc[CAS_R2_NUM_SIGNALS] =

/*  1     2     3     4     5     6     7     8     9    10    11    12    13    14    15  
*/

{   0,    0,    0,    0,    0,    0, 0xf9,    0,    0, 0xfb,    0,    0,    0,    0,    
0}; /*Thailand*/

Benefits

ISUP Transparency Using GTD and R2 Transparency Using GTD

This feature allows optional parameters to be passed transparently through the Cisco SS7 Interconnect for Voice Gateways solution.

R2-to-ISUP Interworking Using GTD

This feature allows different values of CATEGORY and ANSWER signal group B parameters to be passed transparently from the ingress side to the egress side of the Cisco SS7 Interconnect for Voice Gateways solution.

CLIP and CLIR Supplementary Services

This feature allows full mapping of the calling number, screening indicator, and presentation indicator from ISUP to NI2+ to H.323 and supports the following additional services:

•Second calling number

•Network-provided number

•Screening functions on the gateway

•Presentation restriction functions on the gateway

No Change to Existing Interfaces

This feature does not change existing interfaces between modules. It makes use of the cas_relay_signal structure to interface between the R2 register-signaling module and the TSP layer.

Restrictions

To use the ISUP transparency and R2-to-ISUP interworking features on the gateway, one or more properly configured Cisco PGW 2200 signaling controllers are required in the network.

Related Documents

Cisco IOS Documentation

•Cisco IOS Voice, Video, and Fax Configuration Guide, Release 12.2

•Cisco IOS Voice, Video, and Fax Command Reference, Release 12.2

Cisco Gatekeeper Transaction Message Protocol Documentation

•Cisco Gatekeeper External Interface Reference, Version 3.1

Cisco SS7 Interconnect for Voice Gateways Solution Documentation

•Cisco SS7 Interconnect for Voice Gateways Solution Overview 1.3

•SS7 Interconnect for Access Servers and Voice Gateways Solutions Media Gateway Guide

•SS7 Interconnect for Voice Gateways Version 1.3 Provisioning Guide

Cisco Media Gateway Controller Documentation

•Cisco Media Gateway Controller Software Release 9 Provisioning Guide

•Cisco Media Gateway Controller Software Release 9 Operations, Maintenance, and Troubleshooting Guide

•Cisco Media Gateway Controller Software Release Notes

•Cisco Media Gateway Controller Software Release 9 Documentation

Supported Platforms

•Cisco 3660

•Cisco 7200 series

•Cisco AS5300

•Cisco AS5350

•Cisco AS5400

•Cisco AS5800

•Cisco AS5850

Determining Platform Support Through Cisco Feature Navigator

Cisco IOS software is packaged in feature sets that are supported on specific platforms. To get updated information regarding platform support for this feature, access Cisco Feature Navigator. Cisco Feature Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.

Cisco Feature Navigator is a web-based tool that enables you to quickly determine which Cisco IOS software images support a specific set of features and which features are supported in a specific Cisco IOS image. You can search by feature or release. Under the release section, you can compare releases side by side to display both the features unique to each software release and the features in common.

To access Cisco  Feature Navigator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions found at this URL:

http://www.cisco.com/register

Cisco Feature Navigator is updated regularly when major Cisco IOS software releases and technology releases occur. For the most current information, go to the Cisco Feature Navigator home page at the following URL:

http://www.cisco.com/go/fn

Availability of Cisco IOS Software Images

Platform support for particular Cisco IOS software releases is dependent on the availability of the software images for those platforms. Software images for some platforms may be deferred, delayed, or changed without prior notice. For updated information about platform support and availability of software images for each Cisco IOS software release, refer to the online release notes or, if supported, Cisco Feature Navigator.

Supported Standards, MIBs, and RFCs

Standards

•ANSI T1.113, ISDN User Part

•ITU-T Com 16-129-E, H.323 Annex M.2—Tunneling of Signaling Protocol (ISUP) in H.323

•ITU-T Q.783, TUP Test Specification

MIBs

No new or modified MIBs are supported by this feature.

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://tools.cisco.com/ITDIT/MIBS/servlet/index

If Cisco MIB Locator does not support the MIB information that you need, you can also obtain a list of supported MIBs and download MIBs from the Cisco  MIBs page at the following URL:

http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml

To access Cisco MIB Locator, you must have an account on Cisco.com. If you have forgotten or lost your account information, send a blank e-mail to cco-locksmith@cisco.com. An automatic check will verify that your e-mail address is registered with Cisco.com. If the check is successful, account details with a new random password will be e-mailed to you. Qualified users can establish an account on Cisco.com by following the directions found at this URL:

http://www.cisco.com/register

RFCs

No new or modified RFCs are supported by this feature.

Prerequisites

You must configure your Voice over IP (VoIP) network and the Cisco SS7 Interconnect for Voice Gateways solution, including the following components:

•Cisco PGW 2200

•Cisco IOS gateways (GWs)

•Cisco IOS gatekeepers (GKs)

•Route servers

For more information on configuring these components, see the documents in the "Related Documents" section.

You must have the following software installed on your solution components:

•Cisco GW: Cisco IOS Release 12.2(11)T

•Cisco GK: Cisco IOS Release 12.2(11)T

•Cisco PGW 2200: Cisco MGC Software Release 9.1(5)

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Note For more information on the software and components of the Cisco SS7 Interconnect for Voice Gateways solution, refer to the release notes at the following URL:

http://www.cisco.com/univercd/cc/td/doc/product/access/sc/rel7/soln/voip13/voip_rn.htm

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Configuration Tasks

See the following sections for configuration tasks for this feature. Each task in the list is identified as either required or optional.

•Configuring R2 Transparency (optional)

•Verifying R2 Transparency (optional)

•Configuring ISUP Forwarding in H.225 Messages Globally (optional)

•Configuring ISUP Forwarding in H.225 Messages for a Dial Peer (optional)

•Verifying ISUP Forwarding in H.225 Messages (optional)

•Configuring CLIP and CLIR (optional)

•Verifying CLIP and CLIR (optional)

Configuring R2 Transparency

To enable R2 transparency using GTD on the router, use the following commands beginning in global configuration mode:

	Command	Purpose
Step 1	Router(config)# controller e1 4/0	Enters controller configuration mode.
Step 2	Router(config-controller)# cas-custom 0	Selects channel group 0 for configuration and enters CAS custom configuration mode.
Step 3	Router(config-ctrl-cas)# signal-end-to-end	Enables R2 transparency using GTD.

Verifying R2 Transparency

To verify the R2 transparency configuration, perform the following steps:

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Step 1 Enter the show running-config command to display the configuration.

Step 2 Enter the show controllers e1 command.

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Configuring ISUP Forwarding in H.225 Messages Globally

To forward the ISUP GTD payload to the far-end signaled endpoint for all dial peers on the gateway, use the following commands beginning in global configuration mode:

	Command	Purpose
Step 1	Router(config)# voice service voip	Specifies the voice encapsulation type and enters voice-service configuration mode.
Step 2	Router(conf-voi-serv)# signaling forward unconditional	Tunnels the GTD payload in the H.225 SETUP message to the final endpoint in the network.

Configuring ISUP Forwarding in H.225 Messages for a Dial Peer

To forward the ISUP GTD payload to the far-end signaled endpoint for a specific dial peer, use the following commands beginning in global configuration mode:

	Command	Purpose
Step 1	Router(config)# dial-peer voice 1234 {pots | voip}	Enters dial-peer configuration mode. The keywords are as follows: •pots—Indicates that this is a plain old telephone service (POTS) peer using VoIP encapsulation on the IP backbone. •voip—Indicates that this is a VoIP peer using voice encapsulation on the POTS network.
Step 2	Router(config-dial-peer)# signaling forward unconditional	Tunnels the GTD payload in the H.225 SETUP message to the final endpoint in the network.

Verifying ISUP Forwarding in H.225 Messages

To verify the ISUP forwarding configuration, perform the following steps:

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Step 1 Enter the show running-config command to display the configuration. Verify that the correct dial peers were changed.

Step 2 For each dial peer configured, enter the show dial-peer voice command with the number argument for that dial peer, and verify that the dial peer configuration is correct.

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Configuring CLIP and CLIR

To configure CLIP and CLIR, use the following commands beginning in global configuration mode:

	Command	Purpose
Step 1	Router(config)# dial-peer voice 1234 {pots | voip}	Enters dial-peer configuration mode. The keywords are as follows: •pots—Indicates that this is a POTS peer using VoIP encapsulation on the IP backbone. •voip—Indicates that this is a VoIP peer using voice encapsulation on the POTS network.
Step 2	Router(config-dial-peer)# clid restrict	Prevents the calling party number from being presented by calling line ID (CLID).
Step 3	Router(config-dial-peer)# clid strip	Removes the calling party number information from the CLID information and prevents the calling party number from being presented.
Step 4	Router(config-dial-peer)# clid network-number 98765	Configures a network number in the router for CLID and uses it as the calling party number.
Step 5	Router(config-dial-peer)# clid second-number strip	Prevents the second network number from being sent in the CLID information.

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Note In the above table, steps 4 and 5 could be combined into one command. See clid network-number.

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Verifying CLIP and CLIR

To verify the CLIP and CLIR configuration, perform the following steps:

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Step 1 Enter the show running-config command to display the configuration. Verify that the correct dial peers were changed.

Step 2 For each dial peer configured, enter the show dial-peer voice command with the number argument for that dial peer, and verify that the dial peer configuration is correct.

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Configuration Examples

This section provides the following configuration examples:

•R2 Transparency Configuration Example

•CLIP and CLIR Configuration Example

R2 Transparency Configuration Example

The following is a sample configuration for R2 transparency. Commands that appear in the configuration task tables for R2 transparency but that do not appear in the running configuration output are configured for their default settings.

Router# show running-config

! 

! 

! 

controller E1 4/0 

 pri-group timeslots 1-31 nfas_d primary nfas_int 0 nfas_group 0 

! 

controller E1 4/1 

 pri-group timeslots 1-31 nfas_d none nfas_int 1 nfas_group 0 

! 

controller E1 4/2 

 pri-group timeslots 1-31 nfas_d none nfas_int 2 nfas_group 0 

! 

controller E1 4/3 

 pri-group timeslots 1-31 nfas_d primary nfas_int 0 nfas_group 1 

! 

controller E1 4/4 

 ds0-group 0 timeslots 1-15,17-31 type r2-digital r2-compelled 

 cas-custom 0

  country thailand use-defaults 

  metering 

  category 2 

  signal-end-to-end

  answer-signal group-b 5 

! 

controller E1 4/5 

 ds0-group 0 timeslots 1-15,17-31 type r2-digital r2-compelled 

 cas-custom 0

  country thailand use-defaults 

  metering 

  category 2 

  signal-end-to-end

  answer-signal group-b 5 

! 

controller E1 4/6 

 pri-group timeslots 1-31 

! 

! 

! 

CLIP and CLIR Configuration Example

The following is a sample configuration for CLIP and CLIR. Commands that appear in the configuration task tables for CLIP and CLIR but that do not appear in the running configuration output are configured for their default settings.

Router# show running-config

! 

! 

! 

dial-peer voice 123 pots

 destination-pattern 6969

 clid network-number 101010101

 clid second-number strip

 no digit-strip

 direct-inward-dial

 port 6/0:D

!

dial-peer voice 1234 voip

 incoming called-number 6969

!

!

!

Command Reference

This section documents new commands. All other commands used with this feature are documented in the Cisco IOS Release 12.2 command reference publications.

•clid network-number

•clid restrict

•clid second-number strip

•clid strip

•signaling forward

clid network-number

To configure a network number in the router for calling line ID (CLID) and to use it as the calling party number, use the clid network-number command in dial-peer configuration mode. To remove a configured network number from the router, use the no form of this command.

clid network-number number [second-number strip]

no clid network-number number [second-number strip]

Syntax Description

number	Calling party network number.
second-number strip	(Optional) Prevents the second network number from being sent in the CLID information.

Defaults

No default behavior or values.

Command Modes

Dial-peer configuration

Command History

Release	Modification
12.2(11)T	This command was introduced.

Usage Guidelines

This command sets the presentation indicator to "y" and the screening indicator to "network-provided."

Examples

The following example sets the calling party network number to 98765 for POTS dial peer 4321:

Router(config)# dial-peer voice 4321 pots

Router(config-dial-peer)# clid network-number 98765

The following example sets the calling party network number to 56789 for VoIP dial peer 1234, and also prevents the second network number from being sent:

Router(config)# dial-peer voice 1234 voip

Router(config-dial-peer)# clid network-number 56789 second-number strip

Related Commands

Command	Description
clid restrict	Prevents the calling party number from being presented by CLID.
clid second-number strip	Prevents the second network number from being sent in the CLID information.
clid strip	Removes the calling party number information from the CLID information and prevents the calling party number from being presented.

clid restrict

To prevent the calling party number from being presented by calling line ID (CLID), use the clid restrict command in dial-peer configuration mode. To remove the restriction, use the no form of this command.

clid restrict

no clid restrict

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Dial-peer configuration

Command History

Release	Modification
12.2(11)T	This command was introduced.

Usage Guidelines

If this command is issued, the calling party number will still be in the information element, but the presentation indicator will be set to "n" to prevent the presentation.

Examples

The following example prevents the calling party number from being presented:

Router(config-dial-peer)# clid restrict

Related Commands

Command	Description
clid network-number	Configures a network number in the router for CLID and uses it as the calling party number.
clid second-number strip	Prevents the second network number from being sent in the CLID information.
clid strip	Removes the calling party number information from the CLID information and prevents the calling party number from being presented.

clid second-number strip

To prevent the second network number from being sent in the calling line ID (CLID) information, use the clid second-number strip command in dial-peer configuration mode. To allow the second network number to be sent, use the no form of this command.

clid second-number strip

no clid second-number strip

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Dial-peer configuration

Command History

Release	Modification
12.2(11)T	This command was introduced.

Usage Guidelines

This command prevents the H.225 source address field from containing the original calling party number.

---

Note The clid second-number strip command is valid only if a network number has been provisioned previously.

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Examples

The following example prevents the second network number from being sent in the CLID information:

Router(config-dial-peer)# clid second-number strip

An alternative method of accomplishing this is to enter the second-number strip keywords as part of the clid network-number command. The following example sets the calling party network number to 56789 for VoIP dial peer 1234, and also prevents the second network number from being sent:

Router(config)# dial-peer voice 1234 voip

Router(config-dial-peer)# clid network-number 56789 second-number strip

Related Commands

Command	Description
clid network-number	Configures a network number in the router for CLID and uses it as the calling party number.
clid restrict	Prevents the calling party number from being presented by CLID.
clid strip	Removes the calling party number information from the CLID information and prevents the calling party number from being presented.

clid strip

To remove the calling party number information from the calling line ID (CLID) information and to prevent the calling party number from being presented, use the clid strip command in dial-peer configuration mode. To remove the restriction, use the no form of this command.

clid strip

no clid strip

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values.

Command Modes

Dial-peer configuration

Command History

Release	Modification
12.2(11)T	This command was introduced.

Usage Guidelines

If this command is issued, the calling party number will be null in the information element, and the presentation indicator will be set to "n" to prevent the presentation.

Examples

The following example removes the calling party number information from the CLID information and prevents the calling party number from being presented:

Router(config-dial-peer)# clid strip

Related Commands

Command	Description
clid network-number	Configures a network number in the router for CLID and uses it as the calling party number.
clid restrict	Prevents the calling party number from being presented by CLID.
clid second-number strip	Prevents the second network number from being sent in the CLID information.

signaling forward

To choose if a Cisco IOS gateway forwards the Generic Transparency Descriptor (GTD) payload to another gateway, use the signaling forward command. To enable this feature system-wide, use the signaling forward command in voice service voip configuration mode. To enable this feature for an individual voip dial peer, use the signaling forward command in voice dial-peer configuration mode. To disable forwarding, use the no form of this command.

signaling forward {none | unconditional | conditional}

no signaling forward

Syntax Description

none	Prevents the gateway from passing the GTD payload to endpoints in the network.
unconditional	Tunnels the GTD payload in the H.225 message to the final endpoint in the network. The original GTD is sent regardless of any modification by the gatekeeper/route server.
conditional	Specifies forwarding the GTD that is returned from the gatekeeper (because it might be modified when it returns from the gatekeeper). This option is only available under dial-peer configuration mode.

Defaults

none (Signaling forwarding is not enabled.)

Command Modes

Dial-peer configuration (individual dial peers)
Voice service voip configuration (system wide)

Command History

Release	Modification
12.2(11)T	This command was introduced.

Usage Guidelines

This command is used with the Cisco PGW 2200 signaling controller in the Cisco SS7 Interconnect for Voice Gateways solution. You must configure the Cisco PGW 2200 to encapsulate SS7 ISDN User Part messages in GTD format before using this command on the Cisco gateway.

This command does not prevent sending the GTD to a gatekeeper. Any GTD on the originating gateway will be sent to the gatekeeper for use in routing decisions. To prevent GTD creation, the signal-end-to-end command-line interface option on the R2 interfaces should be turned off, and the Cisco PGW 2200 should be configured not to send GTD to the gateway.

Examples

The following example shows unconditional signaling forwarding on a system-wide basis, where the GTD payload is tunneled in H.225 SETUP messages to endpoints:

Router(config)# voice service voip

Router(conf-voi-serv)# signaling forward unconditional

Router(conf-voi-serv)# ^Z

Router# show running-config

Building configuration...

Current configuration : 4201 bytes

!

version 12.2

service config

no service single-slot-reload-enable

no service pad

service timestamps debug uptime

service timestamps log uptime

no service password-encryption

service internal

service udp-small-servers

!

hostname as5300-2

!

no logging buffered

logging rate-limit console 10 except errors

aaa new-model

!

.

.

.

!         

voice service voip 

 signaling forward unconditional

 h323

!

.

.

.

Glossary

BCI—backward call indicator.

CAS—channel-associated signaling.

CCS7—Common Channel Signaling No. 7. Another name for SS7.

CLID—Calling Line ID.

CLIP—Calling Line ID Presentation.

CLIR—Calling Line ID Restriction.

CPC—Nonstandard calling party category.

FDC—Known field compatibility.

GTD—Generic Transparency Descriptor.

H.225.0—An ITU standard that governs H.225.0 session establishment and packetization. H.225.0 actually describes several different protocols: RAS, Q.931, and RTP.

ISDN—Integrated Services Digital Network. Communication protocol offered by telephone companies that permits telephone networks to carry data, voice, and other source traffic.

ISUP—ISDN User Part. Provides the interexchange signaling to support SS7 trunks that are set up for switched voice and data applications in an ISDN environment.

OGW—Cisco originating gateway.

SS7—Signaling System 7. Standard CCS system used with BISDN and ISDN. Developed by Bellcore. Also known as CCS7.

TGW—terminating gateway.

TSP—TAPI service provider.