Introducing Digital Voice Ports (Performing Call Signaling over Digital Voice Ports) Part 5

Digital Voice Port Parameters

After setting up the controller, you can configure voice port parameters for that digital voice port. When you specified a ds0-group, the system automatically created a logical voice port. You must then enter the voice-port configuration mode to configure port-specific parameters. Each voice port you set up in digital voice port configuration is one of the logical voice ports you created with the ds0-group command.

Follow these steps to configure basic parameters for digital T1/E1 voice ports:

Step 1. Enter voice-port configuration mode.

Step 2. Select a two-letter keyword for the voice call progress tones and other locale-specific parameters to be used on this voice port.

Step 3. Specify the companding standard that is used to convert between analog and digital signals.

Note This command is used in cases when a DSP is not used, such as local cross-connects, and overwrites the compand-type value set by the cptone command.

Step 4. Activate the voice port.

Router(config-voiceport)#no shutdown

Figure 4-14 and Example 4-4 illustrate a complete digital voice port configuration that specifies US as the type of call progress tones to use and u-law as the companding type.

Figure 4-14 Digital Voice Port Configuration Topology

Example 4-4 Digital Voice Port Configuration

Configuring T1 CAS Trunks: Inbound E&M FGD and Outbound FGD EANA

Because E&M FGD supports only inbound ANI, a deployment requiring both inbound and outbound ANI can combine an E&M FGD and FGD EANA trunk. The FGD trunk will be used for inbound calls, and the FGD EANA trunk will be used for outbound calls.

T1 CAS with E&M FGD and FGD EANA Trunk Configuration Example

In this example, you have been asked to configure an E1 controller for a voice gateway according to the following network requirements:

■ E1

■ Framing = ESF

■ Line code = B8ZS

■ Time slots 1-12 should be the FGD trunk

■ Time slots 13-24 should be the FGD EANA trunk

■ The voice gateway must support inbound and outbound ANI.

Follow this procedure to configure a T1 CAS digital voice port with inbound and outbound ANI:

Step 1. Enter controller configuration mode.

Step 2. Specify the framing format.

Step 3. Specify line coding.

Step 4. Configure one DS0 group to use time slots 1 to 12 and E&M feature group-D.

Step 5. Configure another DS0 group to use time slots 13 through 24 and E&M feature group-D EANA.

Note This creates two voice ports, 0/0/0:0 and 0/0/0:1.

Step 6. An inbound dial peer is configured using the 0/0/0:0 trunk, which supports inbound ANI:

Step 7. An outbound dial peer is configured using the 0/0/0:1 trunk, which supports outbound ANI:

Figure 4-15 and Example 4-5 illustrate the complete configuration that was previously described.

Figure 4-15 Configuring a T1 CAS Trunk for Inbound and Outbound Calls

Example 4-5 T1 CAS Trunk Configuration Example

Configuring an E1 R2 Trunk

You use the ds0-group controller command to configure E1 R2 trunks as well. The Cisco implementation of R2 signaling has DNIS support enabled by default. If you enable the ANI option, DNIS information is still collected. Specification of the ANI option does not disable the DNIS collection.

T1 CAS with E&M FGD and EANA FGD Trunk Configuration Example

In this example, you have been asked to configure an E1 controller for a voice gateway according to the following network requirements:

■ E1

■ Framing = ESF

■ Line code = B8ZS

■ Time slots 1-31 should use R2 digital signaling

■ The voice gateway must support inbound and outbound DNIS and ANI.

Follow this procedure to configure a T1 CAS digital voice port with inbound and outbound ANI.

Step 1. Enter controller configuration mode.

Step 2. Define DS0 groups.

After the DS0 group has been created, you can tune additional parameters using the cas custom ds0-id command.

Step 3. Customize E1 R2 signaling parameters.

Use the other cas-custom subcommands for further customization required to accommodate a certain PBX or switch. Router(config-ctrl-cas)#country china use-defaults

Use this command to specify the local country, regional, and some corporation settings for R2 signaling. Replace the name variable with one of the supported country names. The default country setting is ITU.

Note Cisco strongly recommends you include the use-defaults option, which enables the default settings for a specific country.

Step 4. Create a dial peer.

Figure 4-16 and Example 4-6 illustrate the complete configuration that was previously described.

Figure 4-16 E1 R2 Trunk Configuration Topology

Example 4-6 E1 R2 Trunk Configuration

Configuring an ISDN Trunk

Many PBX vendors support either T1/E1 PRI or BRI connections. In Europe, where ISDN is more popular, many PBX vendors support BRI connections. When designing how the PBX passes voice to the network, you must ensure the router supports the correct connection. The first step in provisioning ISDN capabilities for T1 or E1 PRI is to enter the basic configuration of the controllers. After the clock source, framing, and line code are configured, ISDN voice functionality requires these configuration commands:

■ isdn switch-type: Configures the ISDN switch type. You can enter this parameter in global configuration mode or at the interface level. If you configure both, the interface switch type takes precedence over the global switch type. This parameter must match the provider ISDN switch. This setting is required for both BRI and PRI connections.

■ pri-group: Configures time slots for the ISDN PRI group. T1 allows for time slots 1 through 23 to be configured as B channels, with time slot 24 allocated to the data channel (D channel). E1 allows for time slots 1 through 31, with time slot 16 allocated to the D channel. You can configure the PRI group to include all available time slots, or you can configure only a select group of time slots.

■ isdn incoming-voice: Configures the interface to send all incoming calls to the DSP card for processing.

■ isdn switch-type [primary-qsig I basic-qsig]: Configures the use of QSIG signaling on the D channel. You typically use this setting when connecting via ISDN to a PBX. The command to enable QSIG signaling is isdn switch-type primary-qsig for PRI and isdn switch-type basic-qsig for BRI connections.

Figure 4-17 and Example 4-7 show the configuration for a PBX connection to the Cisco voice-enabled router. The connection is configured for QSIG signaling across all 23 time slots.

Figure 4-17 ISDN Configuration Topology Example

Example 4-7 ISDN Configuration

The following steps detail the previous configuration:

Step 1. Specify the CO switch type on the ISDN interface.

You have a choice of configuring the isdn-switch-type command to support QSIG at either the global configuration level or at the interface configuration level.

Step 2. Enter controller configuration mode.

Step 3. Specify an ISDN PRI group.

Step 4. Enter voice port configuration mode for the D channel. Channel 23 is the D channel because the channel numbering begins at 0. Therefore, Channel 23 is the 24th channel.

Step 5. Send incoming calls to DSPs.

Step 6. Activate the voice port.