Versatile Interface Processor-Based Distributed FRF.12
Appendix
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Appendix

Table Of Contents

Appendix

Preparing to Configure Voice Dial Peers

Organize Voice Network Information

Create a Peer Configuration Table

Configuring Dial Peers

Configuring Voice over Frame Relay Dial Peers

Configure Voice over Frame Relay Dial Peers for Tandem Nodes

Configuring Voice over Frame Relay Connections

Overview of Voice over Frame Relay Connection Types

Configuring Connections for Tandem Nodes

Verifying Your Voice Connections

Troubleshooting Tips

Monitoring and Maintaining Your Voice over Frame Relay Configuration


Appendix

This section provides information that might be helpful for individual using the Voice over Frame Relay Using FRF. 12 for the VIP feature. This Appendix includes the following sections:

Preparing to Configure Voice Dial Peers

Configuring Dial Peers

Configuring Voice over Frame Relay Connections

Preparing to Configure Voice Dial Peers

After you have analyzed your dial plan and decided how to integrate it into your existing network, you are ready to configure your network devices to support VoFR. The actual configuration procedure depends entirely upon the topology of your voice network, but, in general, you need to perform the following tasks:

Organize Voice Network Information

Create a Peer Configuration Table


Timesaver If possible, you might want to configure the Frame Relay dial peers in a back-to-back configuration before separating them across the Frame Relay network. You can use a back-to-back configuration to test your VoFR and dial-peer configuration to determine if you can make a voice connection. Then, when you place both peers on the network, failure to make a voice connection will isolate the cause as a network problem.


Organize Voice Network Information

After you have configured your Frame Relay network, you should collect all of the data directly related to each dial peer by creating a peer configuration table to prepare for configuring VoFR.

Create a Peer Configuration Table

Specific information relative to each dial peer needs to be identified before you can configure VoFR. One way to identify this information is to create a peer configuration table.

Figure 1 shows a diagram of a small voice network in which router No. 1 connects a small sales branch office to the main office through router No. 2. Only two devices in the sales branch office that need to be established as dial peers: a telephone and a fax machine. Router No. 2 is the primary gateway to the main office; as such, it needs to be connected to the company's PBX. Two telephones and one fax machine connected to the PBX need to be established as dial peers in the main office.

Table 1 shows the peer configuration table for the example illustrated in Figure 1.

Figure 1 Sample VoFR Network

Table 1

Dial Peer
Extension
Prefix
Destination Pattern
Type
Voice Port
Session Target
Router No. 1
         

1

61111

 

13107661111

POTS

1/0/0

 

2

62222

 

13107662222

POTS

1/0/1

 

10

   

1310767....

VOFR

 

S0/0 150

Router No. 2
         

11

   

1310766....

VOFR

 

S0/0 150

3

73333

7

1310767....

POTS

1/0/0

 

4

74444

7

1310767....

POTS

1/0/0

 

5

75555

7

1310767....

POTS

1/1

 

Peer Configuration Table for Sample VoFR Network

The dial plan shown in Table 1 lists a simple dial-peer configuration table. No configuration for forwarding digits to a PBX is shown. Additional configuration for this is required.

Configuring Dial Peers

Dial peers describe the entities to and from which a call is established. Dial-peer configuration tasks define the address or set of addresses serviced by that dial peer and the call parameters required to establish a call to and from that dial peer.

Two different kinds of dial peers pertain to VoFR configurations:

POTS—Dial peer connected via a traditional telephony network. Voice-telephony peers point to a particular voice port on a voice-network device.

VoFR—Dial peer connected via a Frame Relay WAN backbone. VoFR dial peers point to specific voice-network devices. For Voice over Frame Relay, you can configure VoFR dial peers for the following call types:

Switched calls

Cisco-trunk permanent calls

POTS peers associate a telephone number with a particular voice port so that incoming calls for that port can be received. VoFR peers point to specific voice-network devices (by associating destination telephone numbers with a specific Frame Relay DLCI) so that outgoing calls can be placed. Both POTS and VoFR dial peers are needed to establish VoFR connections if you want both to send and receive calls.

For tandem voice nodes, POTS dial peers are not configured.

Establishing two-way communication using VoFR requires establishing a specific voice connection between two defined endpoints. As shown in Figure 2, for outgoing calls (from the perspective of the voice-telephony dial peer 1), the voice-telephony dial peer establishes the source (the originating telephone number and voice port) of the call. The voice-network dial peer establishes the destination by associating the destination telephone number with a specific Frame Relay DLCI.

Figure 2 Calls from the Perspective of Router No.1

In the example, the destination pattern 14085554000 string maps to a U.S. telephone number 555-4000, with the digit 1 plus the area code (408) preceding the number. When you configure the destination pattern, set the dial string to match the local dial conventions.

To complete the two-way communications loop, you need to configure VoFR dial peer 4 as shown in Figure 3.

Figure 3 Calls from the Perspective of Router No. 2

When you configure dial peers, ensure that you understand the relationship between the destination pattern and the session target. The destination pattern is the telephone number of the voice device attached to the voice port. The session target represents the route to a serial port on the peer router at the other end of the Frame Relay connection. Figure 4 and Figure 5 show the relationship between the destination pattern and the session target, as seen from the perspective of both routers in a VoFR configuration. These examples show a topology for switched calls only.

Figure 4 Relationship between Destination Pattern and Session Target from the Perspective of Router No. 1

Figure 5 Relationship between Destination Pattern and Session Target from the Perspective of Router No. 2

The following sections describe how to configure POTS peers and VoFR peers.

Configuring Voice over Frame Relay Dial Peers

To configure a VoFR dial peer, you need to uniquely identify the peer (by assigning it a unique tag number) and define the outgoing serial port number and the virtual circuit number.

Depending on your dial plan configuration, you might need to consider how to configure voice networks with variable-length dial plans, number expansion, excess digit playout, forward digits, and default voice routes, or use hunt groups with dial peer preferences.

For VoFR dial peer configuration procedures, refer to the following section:

Configure Voice over Frame Relay Dial Peers for Tandem Nodes

Figure 6 shows an example of a Frame Relay network with switched calls. In the example, there are two routers (Routers No. 1 and No. 2) with telephone devices at the endpoints. In between the two endpoint routers are tandem routers (Routers A, B, and C) with switched connections in between. Standard VoFR dial peers are configured on the intermediate nodes in the Frame Relay network. Support for switched calls are configured on the dial peers on both Router No. 1 and Router No 2.

Figure 6 Endpoint Nodes and Tandem Nodes in VoFR Network for Switched Calls

In this example, different types of VoFR dial peers have to be configured on the different routers.

VoFR dial peers for switched connections must be configured between Router No. 1 and Router No. 2 (the endpoints for the voice connection)

On the tandem routers (Routers A, B, and C) VoFR dial peers for switched calls must be configured for the following:

Between Router No. 1 and Router A

Between Router No. 1 and Router B

Between Router No. 2 and Router A

Between Router No. 2 and Router C

Between Router A and Router B

Between Router B and Router C

Configure Voice over Frame Relay Dial Peers for Tandem Nodes

You configure standard VoFR dial peers for switched calls on the tandem routers in the network topology.

You can configure VoFR dial peers for tandem routers on the Cisco MC3810 and on Cisco 7500 series routers.


Note Cisco 7500 series routers with a VIP can serve as tandem nodes in the VoFR network.


To configure VoFR dial peers on tandem routers, use the following commands from configuration mode:

 
Command
Purpose

Step 1 

router(config)# dial-peer voice number vofr

Define a VoFR dial peer and enter dial-peer configuration mode. All subsequent commands that you enter in dial-peer voice mode before you exit will apply to this dial peer.

The number value tag identifies the dial peer and must be unique on the router. Do not duplicate a specific number tag.

Step 2 

router(config-dialpeer)# destination-pattern 
[+]string[t]

Configure the dial peer's destination pattern. The same restrictions for the string listed in the POTS dial-peer configuration also apply to the VoFR destination pattern.

Step 3 

router(config-dialpeer)# session target interface dlci 

Configure the Frame Relay session target for the dial peer.

Step 4 

router(config-dialpeer)# preference value

(Optional) Configure a preference for the VoFR dial peer. The value is a number from 0 to 10 where the lower the number, the higher the preference in hunt groups.

Step 5 

To configure the next VoFR dial peer, exit dial-peer configuration mode by entering exit, and repeat the previous steps. On tandem nodes, at least two VoFR dial peers are required, one for each call leg in the router.

Configuring Voice over Frame Relay Connections

After you have configured the Frame Relay DLCI settings and you have configured your dial plan, you are ready to configure specific VoFR connections.

There are many different scenarios for VoFR connections. For information on the different connection types, see the next section, "Overview of Voice over Frame Relay Connection Types."

For procedures on how to configure the different connection types, see the following sections:

Overview of Voice over Frame Relay Connection Types

Configuring Connections for Tandem Nodes

Verifying Your Voice Connections

Troubleshooting Tips

Monitoring and Maintaining Your Voice over Frame Relay Configuration

In addition, special consideration is required for configuring calls for tandem nodes. For more information, see "Configuring Connections for Tandem Nodes" section.

Overview of Voice over Frame Relay Connection Types

When you configure VoFR connections, there are many different connection types possible depending on the hardware platform if the call is to be a regular switched (user dialed or auto-ringdown) call. You configure these specific connection types using combinations of several commands.

This section only details Voice Over Frame Relay connection types that are currently available with Cisco 7500 series routers with a VIP. Table 2 lists the different connection types for VoFR connections supported on the Cisco 7500 series with a VIP, and the combinations of commands to enter for each call type.

Table 2 Voice over Frame Relay Connection Types Supported on the Cisco 7500 Series with a VIP 

Type of Call
Frame Relay DLCI interface Command to Enter
Data Fragmentation Supported by vofr Command
Session Protocol Command to enter in dial peer mode

Switched call
(user dialed or auto-ringdown)
to a Cisco MC3810

vofr cisco1

Cisco  proprietary2

session protocol cisco-switched

1 This command consumes data CID 4 and call-control CID 5.

2 Cisco proprietary fragmentation is based on an early draft of FRF.12, and is compatible with Cisco MC3810 concentrators running software versions prior to Cisco IOS Release 12.0(3)XG or 12.0(4)T.


Configuring Connections for Tandem Nodes

Tandeming is the switching of an incoming VoFR call on a Frame Relay DLCI to an outgoing VoFR enabled DLCI. Tandeming works for switched calls and Cisco-trunk permanent calls only. .

Tandeming is supported on the Cisco 7500 series routers with a VIP. The Cisco 7500 series router with a VIP can only act as a tandem router in a VoFR network.

Depending on which router is used as the end node and which router is used as the tandem node, you must use the correct Frame Relay PVC type when configuring your connections. Table 3 shows the different combinations of routers that can serve as end nodes and tandem nodes, and the Frame Relay PVC type required.

Table 3 VoFR End Node and Tandem Node Combinations Supported

End Node(s)
Tandem Node
vofr Command to Enter for the Frame Relay DLCI

Cisco 2600/3600

Cisco 2600, Cisco 3600, Cisco 7200, or Cisco 7500

vofr call-control

Cisco 2600/3600 and Cisco MC3810

Cisco MC3810 or Cisco 7500

vofr cisco

Cisco MC3810

Cisco 2600, Cisco 3600, Cisco 7200, or Cisco 7500

vofr cisco


When you configure a tandem node, you must configure two VoFR dial peers, one for each tandem connection.

Verifying Your Voice Connections

Verify that the voice connection for switched calls is working by doing the following:

Pick up the handset on a telephone connected to the configuration and verify that you can get a dial tone.

Make a call from the local telephone to a configured dial peer and verify that the call attempt is successful.

Verify that the voice connection for FXO-FXS trunk calls from a telephone to a remote PBX is working by doing the following:

Pick up the telephone and listen to hear the dial tone from the remote PBX.

Dial digits so that the remote PBX routes the call.

You can check the validity of your dial-peer and voice-port configuration by performing the following tasks:

If you have relatively few dial peers configured, you can use the show dial-peer voice command to verify that the data configured is correct.

To show the status of the voice ports, use the show voice port command.

To show the call status for all voice ports, use the show call active voice [brief].

Troubleshooting Tips

If you are having trouble connecting a call, you can try to resolve the problem by performing the following tasks:

If no calls are going through, make sure the frame-relay voice bandwidth command is configured.

If you have Voice over Frame Relay configured on a PVC and are experiencing problems with data connectivity on that PVC, make sure the frame-relay fragment command has been configured.

If you suspect the problem is with the dial plan or the dial peers, use the show dial-plan number dial string command to display which dial peers are used when a specific number is called.

Be sure the voice port, serial port, and/or the T1/E1 controller are set to no shutdown.

Insure that frame-relay fragmentation is configured on both ends of the link.

Monitoring and Maintaining Your Voice over Frame Relay Configuration

Use the following commands to monitor and maintain your Voice over Frame Relay configuration:

Command
Purpose
Router# show call active voice [brief]

Displays the active call table.

Router# show call history voice [last number] | [brief]

Displays the call history table.

Router# show dial-peer voice

Displays configuration information and call statistics for dial peers.

Router# show frame-relay fragment

Displays information about the Frame Relay fragmentation taking place in your Cisco router.

Router# show frame-relay pvc

Displays statistics about PVCs for Frame Relay interfaces.

Router# show interfaces serial

Displays information about a serial interface.

Router# show policy-map interface

Displays information about the contents on a service policy.

Router# show voice permanent-call

Displays information about the permanent calls on a voice interface.