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This chapter shows you how to configure Voice over Frame Relay on the Cisco MC3810 concentrator. For a description of the commands used to configure Voice over Frame Relay, refer to the "Voice-Related Commands" chapter in the Voice, Video, and Home Applications Command Reference.
Voice over Frame Relay enables a Cisco MC3810 concentrator to carry voice traffic (for example, telephone calls and faxes) over a Frame Relay network. Voice over Frame Relay on the Cisco MC3810 is supported on serial ports 0 and 1, as well as on the T1/E1 trunk.
This chapter describes the commands to specifically configure Voice over Frame Relay on the Cisco MC3810. It is assumed you have already configured your Frame Relay backbone network. As part of your Frame Relay configuration, you need to configure the map class, and the Local Management Interface (LMI) among other Frame Relay functionality. For more information about Frame Relay configuration, see the Wide-Area Networking Configuration Guide.
Call leg---A logical connection between the router and either a telephony endpoint over a bearer channel, or another endpoint using a session protocol.
CIR---Committed information Rate. The average rate of information transfer a subscriber (for example, the network administrator) has stipulated for a Frame Relay PVC.
CODEC---coder-decoder. Device that typically uses pulse code modulation to transform analog signals into a digital bit stream and digital signals back into analog signals. In Voice over IP, it specifies the voice coder rate of speech for a dial peer.
DCE---Data communications equipment.
DLCI---Data-link connection identifier.
Dial peer---An addressable call endpoint. In Voice over IP, there are two kinds of dial peers: POTS and VoIP.
DS0---A 64-K B-channel on an E1 or T1 WAN interface.
DTE---Data terminal equipment.
DTMF---Dual tone multifrequency. Use of two simultaneous voice-band tones for dial (such as touch tone).
E&M---E&M stands for recEive and transMit (or Ear and Mouth). E&M is a trunking arrangement generally used for two-way switch-to-switch or switch-to-network connections. Cisco's E&M interface is an RJ-48 connector that allows connections to PBX trunk lines (tie lines).
FXO---Foreign Exchange Office. An FXO interface connects to the PSTN's central office and is the interface offered on a standard telephone. Cisco's FXO interface is an RJ-11 connector that allows an analog connection to be directed at the PSTN's central office. This interface is of value for off-premise extension applications.
FXS---Foreign Exchange Station. An FXS interface connects directly to a standard telephone and supplies ring, voltage, and dial tone. Cisco's FXS interface is an RJ-11 connector that allows connections to basic telephone service equipment, keysets, and PBXs.
PBX---Private Branch Exchange. Privately owned central switching office.
PLAR---Private Line Auto Ringdown. This type of service results in a call attempt to some particular remote endpoint when the local extension is taken off-key.
POTS---Plain Old Telephone Service. Basic telephone service supplying standard single line telephones, telephone lines, and access to the public switched telephone network.
POTS dial peer---Dial peer connected via a traditional telephony network. POTS peers point to a particular voice port on a voice network device.
PSTN---Public Switched Telephone Network. PSTN refers to the local telephone company.
PVC---Permanent virtual circuit.
Trunk---Service that allows quasi-transparent connections between two PBXs, a PBX and a local extension, or some other combination of telephony interfaces to be permanently conferenced together by the session application and signaling passed transparently through the IP network.
UIO---Universal I/O serial port (Cisco MC3810)
VoFR dial peer---Dial peer connected via a Frame Relay network. VoFR peers point to specific VoFR devices.
Before you can configure your Cisco MC3810 concentrator to use Voice over Frame Relay, you must first:
After you have analyzed your dial plan and decided how to integrate it into your existing Frame Relay network, you are ready to configure your network devices to support Voice over Frame Relay.
To configure Voice over Frame Relay, you need to perform the following tasks:
You must configure your Frame Relay network to support real-time voice traffic before you configure Voice over Frame Relay. The preliminary tasks include the following:
(a) Configuring a map class for a group of DLCIs.
(b) Configuring the DLCI(s) to support voice traffic.One of the key steps is to configure the DLCI to support data segmentation of the voice traffic. Make sure to set the data segmentation size to match the line rate, or the port access rate. Configure the same data segmentation size value on both Cisco MC3810 concentrators on the voice connection.
Although not mandatory, there are some preliminary tasks you can complete to make dial peer configuration easier. They include:
(a) Organizing voice network information.
(b) Creating a peer configuration table.
Configure dial peers. Each dial peer defines the characteristics associated with a call leg. A call leg is a discrete segment of a call connection that lies between two points in the connection. An end-to-end call is comprised of four call legs, two from the perspective of the source access server, and two from the perspective of the destination access server. Dial peers are used to apply attributes to call legs and to identify call origin and destination.
There are two different kinds of dial peers:
(a) POTS---Dial peer describing the characteristics of a traditional telephony network connection. POTS peers point to a particular voice port on a voice network device.
(b) VoFR---Dial peer describing the characteristics of a Frame Relay network connection. VoFR peers point to specific VoFR devices.
As part of the dial-peer configuration, you can configure forward digits and configure the preference level of a dial peer to support hunt groups. When planning your dial plan, consider using hunt groups to hunt for dial peers. For more information about configuring these dial peer parameters, refer to the "Advanced Dial Peer Configuration" section.
4. Configure Voice Ports
Configure your Cisco MC3810 concentrator to support voice ports. In general, voice-port commands define the characteristics associated with a particular voice-port signaling type. Voice ports on the Cisco MC3810 support three basic voice signaling types:
(a) FXO---Foreign Exchange Office interface.
(b) FXS---The Foreign Exchange Station interface.
(c) E&M---The "Ear and Mouth" (or "RecEive and TransMit") interface.
Under most circumstances, the default voice-port command values are adequate to configure FXO and FXS ports to transport voice data over your existing IP network. Because of the inherent complexities involved with PBX networks, E&M ports might need specific voice-port values configured, depending on the specifications of the devices in your telephony network. For more information about configuring voice ports, refer to the "Configuring Voice Port" chapter.
You can perform any of the procedures, depending on your application.
Before configuring a Frame Relay data-link connection identifier (DLCI) for voice traffic, you can configure a Frame Relay map class to assign traffic shaping properties to a group of DLCIs. If you have a large number of permanent virtual circuits (PVCs) to configure, you can assign the PVCs the same traffic shaping properties without statically defining the values for each PVC.
Configuring a Frame Relay map class is optional. You can create multiple map classes, with different variables for each map class. If you want to skip this task, proceed to the next section.
To configure a Frame Relay map class for a group of DLCIs, use the following commands beginning in configuration mode:
| Step | Command | Purpose | ||
|---|---|---|---|---|
| map-class frame-relay map-class-name | Create a map-class name you will assign to a group of PVCs. The map-class-name must be unique. | ||
| frame-relay be in bits | Configure the incoming excess burst size for this group of PVCs. | ||
| frame-relay be out bits | Configure the outgoing excess burst size for this group of PVCs. | ||
| frame-relay adaptive-shaping becn | |||
| exit | Exit map-class configuration mode. |
When configuring a Frame Relay PVC to support voice traffic, you must ensure that the carrier can accommodate the traffic rate or profile transmitted on the PVC. If too much traffic is sent at once, the carrier may discard frames, which causes disruptions to real-time voice traffic. Or, the carrier may deal with traffic bursts by queuing up the bursts and delivering them at a metered rate. Excessive queuing also causes disruption to real-time voice traffic.
To compensate for this, it is recommended that you configure Frame Relay traffic shaping, and that you configure the traffic profile parameters specified with the map class. For more information on configuring the map class, see the previous section.
To configure a Frame Relay DLCI to support voice traffic, use the following commands beginning in configuration mode:
| Step | Command | Purpose | ||
|---|---|---|---|---|
| controller {t1 | e1} number | If configuring Voice over Frame Relay over the T1/E1 trunk (T1/E1 0), enter the controller configuration mode. If configuring Voice over Frame Relay over serial port 0 or 1, proceed to Step 5. If the Digital Voice Module (DVM) is installed, the controller number can be either 0 or 1. If the Multiflex-Trunk (MFT) is installed, the number must be 0. | ||
| channel-group channel-no timeslots timeslot-list speed {56 | 64} | Configure the channel group number and the timeslot list for the controller. The channel group is a number from 0 to 23. The timeslot-list is a number from 1 to 24. The channel group number must be unique, and cannot be the same as a configured CAS group or voice group. | ||
| exit | Exit controller configuration mode. | ||
| interface serial 0: x | If configuring Voice over Frame Relay over the T1/E1 trunk, enter interface configuration mode by specifying serial 0:x, where x is the channel group number you configured in the previous step. In the previous Cisco IOS Release 11.3(1) MA, serial port 2 was a valid port number. Beginning with Release 12.0, serial 2 is not a valid designation on the Cisco MC3810. You must enter the channel group number. Proceed to Step 6. | ||
| interface serial number | If configuring Voice over Frame Relay over serial port 0 or 1, enter interface configuration mode and configure the serial interface. You can specify serial port 0 or 1 for traffic over the Universal I/O (UIO) serial ports. | ||
| encapsulation frame-relay [ietf] | |||
| clock rate network clock rate | If configuring back-to-back Frame Relay, set the network clock rate in kbps for the data communications equipment (DCE) side on serial ports 0 and 1 only. The valid range is from 56 to 2048 kbps, and the value must be a multiple of the value set using the network-clock base-rate command. | ||
| dce terminal-timing enable | If configuring back-to-back Frame Relay, configure the DCE port to use its own clock signal to prevent phase shifting of the data with respect to the clock. | ||
| frame-relay traffic-shaping | If a Frame Relay map class was not configured and assigned to this DLCI, enable Frame Relay traffic shaping on the interface. Make sure to use Frame Relay traffic shaping only; do not use generic traffic shaping. Note Frame Relay traffic shaping should be enabled on the interface if sending voice and data traffic over a single Frame Relay PVC over a public Frame Relay network. If sending voice and data traffic over a back-to-back Frame Relay configuration, or on a private Frame Relay network, traffic shaping is not required. | ||
| frame-relay interface-dlci dlci voice-encap size |
You must configure the voice encapsulation option to support voice traffic. Set the data segmentation size to match the line rate, or the port access rate. Configure the same data segmentation size value on both Cisco MC3810 concentrators on the voice connection. For more information about recommended data segmentation sizes, see Table 7. When the voice-encap option is configured, all priority queuing, custom queuing, and weighted fair queuing is disabled on the interface. Note The voice-encapsulation option applies only to the transmit DLCI side. This option sends the Frame Relay stream through a segmentation engine that is similar to FRF.12. | ||
| class name | Associate the DLCI with a map class that you configured in the previous section. The traffic shaping properties associated with the map class will be assigned to the DLCI. | ||
| exit | Exit DLCI configuration mode. |
If the serial interface was configured for multipoint operation, repeat Steps 10 through 12 for each subinterface.
| Access Rate | Recommended Data Segmentation Size1 |
|---|---|
64 kbps | 80 bytes |
128 kbps | 160 bytes |
256 kbps | 320 bytes |
512 kbps | 640 bytes |
1536 kbps (full T1) | 1600 bytes |
2048 kbps (full E1) | 1600 bytes |
| 1The data segmentation size is based on back-to-back Frame Relay. If sending traffic through an IGX with standard Frame Relay, subtract 6 bytes from the recommended data segmentation size. |
When configuring Voice over Frame Relay in back-to-back hard-wired configurations, make sure one side of the voice connection is configured as DCE and the other side is configured as DTE. The Voice over Frame Relay configuration must be performed on the Cisco MC3810 concentrators on both sides of the voice connection.
To configure switched Frame Relay to support voice traffic, use the following command in configuration mode:
| Command | Purpose |
|---|---|
frame-relay switching | Enable PVC switching on the Cisco MC3810. |
 | 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. Using a back-to-back configuration, you can test your Voice over Frame Relay and dial-peer configuration to see if you can successfully make a voice connection. Then, when you place both peers on the network, if you cannot make a voice connection, you can isolate the cause as a network problem. For an example of a back-to-back Voice over Frame Relay configuration, see the "Voice over Frame Relay Configuration Examples" section. |
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 Voice over Frame Relay.
Figure 15 shows a diagram of a small voice network in which Router 1 connects a small sales branch office to the main office through Router 2. There are only two devices in the sales branch office that need to be established as dial peers: a basic telephone and a fax machine. Router 2 is the primary gateway to the main office; as such, it needs to be connected to the company's private branch exchange (PBX). There are two basic telephones and one fax machine connected to the PBX that need to be established as dial peers in the main office.
Table 8 shows the peer configuration table for the example illustrated in Figure 15.
| Dial Peer | Ext | Prefix | Destination-Pattern | Type | Voice Port | Session Target |
|---|---|---|---|---|---|---|
| Router 1 |
|
|
|
|
|
|
1 | 61111 |
| 13101161111 | POTS | 1/1 |
|
2 | 62222 |
| 13101162222 | POTS | 1/2 |
|
10 |
|
| 1310117.... | VOFR |
| S0 150 |
| Router 2 |
|
|
|
|
|
|
11 |
|
| 1310116.... | VOFR |
| S0 150 |
3 | 73333 | 7 | 1310117.... | POTS | 1/1 |
|
4 | 74444 | 7 | 1310117.... | POTS | 1/1 |
|
5 | 75555 | 7 | 1310117.... | POTS | 1/1 |
|
The dial plan shown in Table 8 lists a simple dial-peer configuration table, with no special configuration for how you forward or playout excess digits. For more information on other options for designing your dial plan and configuring your dial peers to connect with PBXs, see the "Advanced Dial Peer Configuration" section.
There are two different kinds of dial peers:
POTS peers associate a telephone number with a particular voice port so that incoming calls for that port can be received. Voice over Frame Relay 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 Voice over Frame Relay dial peers are needed to establish Voice over Frame Relay connections if you want to both send and receive calls.
For tandem voice nodes, POTS dial peers are not required.
Establishing two-way communication using Voice over Frame Relay requires establishing a specific voice connection between two defined endpoints. As shown in Figure 16, 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 phone number with a specific Frame Relay DLCI.
In the example, the destination pattern 14085554000 string maps to a U.S. phone number 555-4000, with the digit 1 plus the area code (408) preceding the number. When configuring 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 17.
The only exception to this is when both POTS dial peers are connected to the same concentrator, as shown in Figure 18. In this circumstance, you would not need to configure a Voice over Frame Relay dial peer.
When configuring dial peers, you need to 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 Cisco MC3810 at the other end of the Frame Relay connection. Figure 19 and Figure 20 show the relationship between the destination pattern and the session target, as seen from the perspective of both Cisco MC3810 concentrators in a Voice over Frame Relay configuration.
To configure POTS dial peers, use the following commands beginning in configuration mode:
| Step | Command | Purpose | ||
|---|---|---|---|---|
| dial-peer voice tag pots |
The tag value identifies the dial peer and must be unique on the Cisco MC3810. Do not duplicate a specific tag number. | ||
| destination-pattern string | Configure the dial peer's destination pattern. The string is a series of digits that specify the E.164 or private dialing plan telephone number. Valid entries are the digits 0 through 9 and the letters A through D. The following special characters can be entered in the string:
| ||
| port slot/port | Associate this voice-telephony dial peer with a specific logical dial interface. Enter the slot/port number of the voice port connected to the POTS dial peer. | ||
| forward-digits {num-digit | all} | (Optional) If using the forward-digits feature, configure the digit-forwarding method that will be used on the dial peer. | ||
| prefix string | (Optional) If the forward-digits feature was not configured in the last step, assign the dialed digits prefix for the dial peer. | ||
| preference value |
For more information about hunt groups and preferences, see the "Hunt Groups and Preference Configuration" section. |
To configure additional POTS dial peers, exit dial-peer configuration mode by entering exit, and repeat the previous steps.
To configure Voice over Frame Relay dial peers, use the following commands beginning in configuration mode:
| Step | Command | Purpose | ||
|---|---|---|---|---|
| dial-peer voice tag vofr |
The tag value identifies the dial peer and must be unique on the Cisco MC3810. Do not duplicate a specific tag number. | ||
| destination-pattern string | |||
| session target interface Serial interface dlci | Configure the Frame Relay session target for the dial peer. | ||
| preference value | (Optional) Configure a preference for the Voice over Frame Relay dial peer. The value is a number from 0 to 10 where the lower the number, the higher the preference. For more information about hunt groups and preferences, see the "Hunt Groups and Preference Configuration" section. | ||
| alt-dial string | (Optional) Configure the alternate dial-out string when configuring on-net-to-off-net alternative dialing. |
To configure additional Voice over Frame Relay dial peers, exit dial-peer configuration mode by entering exit, and repeat the previous steps.
Depending on your configuration, you may need to consider how to configure voice networks with excess digit playout, forward digits and default voice routes, or use hunt groups with dial-peer preferences. For more information on these topics, see the "Advanced Dial Peer Configuration" section.
Verify that the voice connection is working by doing the following:
You can check the validity of your dial peer and voice-port configuration by performing the following steps:
If you are having trouble connecting a call, you can try to resolve the problem by performing the following tasks:
Depending on the configuration, you may need to consider different strategies for how you configure the dial plan, and how you configure the dial peers. This section describes the following topics regarding dial peer configuration that you may need to consider:
Excess digits are defined as received digits that are beyond the length of the destination pattern on a terminating router. A terminating router will forward excess digits to the telephony interface. For example, if the digits "123456789" are matched on a terminating router with a destination pattern of "1.....," the "6789" are excess digits and will be forwarded.
A router that is originating a call will only collect digits up to the length of a defined destination pattern. When a number is dialed that is longer than the destination pattern, after the last digit in the destination pattern is dialed, the call is immediately placed, and the additional digits are not collected by the Cisco MC3810.
For example, if the digits "123456789" are dialed on an originating Cisco MC3810 with a destination pattern of 1...., then "6789" are not collected. The call is placed immediately after the digit "5" is dialed. The additional digits "6789" are not collected, but are passed through the audio path.
In configurations where a phone on an FXS port on the Cisco MC3810 is connected to the PSTN through an FXO port on the same Cisco MC3810, additional steps are necessary to enable a call to go through. Because the uncollected excess digits are passed through the audio path, the excess digits might not go through if the audio path isn't ready when the excess digit is dialed. When dialing a destination pattern in this situation, pause and wait for a second dial tone before dialing the excess digits. This will give the audio path time to accept the excess digits.
Voice default routing for fixed-length dial plans can be used with larger PBX configurations to forward digits to Cisco MC3810 telephony interfaces.
Figure 21 shows an example of routing voice calls through a PBX using forward digits. In the configuration, the Cisco MC3810-t and Cisco MC3810-T are tandem nodes, and are required to support forwarding digits so that calls from Cisco MC3810s 0, 5, or 9 can make a call to extension "8208."
On the two tandem nodes, the forward-digits command is required. This command specifies to forward all digits matched with the destination "8..." to the appropriate port. For a call from Cisco MC3810-0 to reach extension 8208, the call must first terminate at Cisco MC3810-T, which plays out the digits "8208" to the voice port connected to the PBX. The PBX then routes the voice call to Cisco MC3810-t. On the tandem nodes, although the forward-digits all command is used, the forward-digits 4 command can also be used in this example.
The following are the dial-peer configurations on each Cisco MC3810 required for this configuration:
dial-peer voice 8 pots
destination-pattern 8208
session-target s0 1 dial-peer voice 1000 pots
destination-pattern 8...
forward-digits all
port 1/1 dial-peer voice 9999 pots
destination-pattern ....
forward-digits all
port 1/1
dial-peer voice 1 vofr
destination-pattern 8200
session-target s0 1 dial-peer voice 6 vofr
destination-pattern 8209
session-target s0 6 dial-peer voice 10 vofr
destination-pattern 8209
session-target s0 10 dial-peer voice 1 pots
destination-pattern 8...
forward-digits all
port 1/1
dial-peer voice 1 pots
destination-pattern 8200
port 1/1 dial-peer voice 1000 vofr
destination-pattern8...
session-target s0 1 For Cisco MC3810-5: dial-peer voice 5 pots
destination-pattern 8205
port 1/1 dial-peer voice 1000 vofr
destination-pattern 8...
session-target s0-1
dial-peer voice 9 pots
destination-pattern 8209
port 1/1 dial-peer voice 1000 vofr
destination-pattern 8...
session-target s0 1
The concept of voice default routes is also shown in Figure 21 and in the configuration. In the example, the configurations for the destination dial plans "8..." in both the tandem nodes are voice default routes because all voice calls dialed that start with 8 followed by three digits will either match on 8208 or end up with 8...., which is the last resort voice route used by Cisco MC3810-t if no other route is discovered.
For example, in the following dial-peer configuration, there are four POTS dial peers configured, all with a different destination pattern on the same PBX:
dial-peer voice 1 pots
destination-pattern 3001
port 1/1 dial-peer voice 2 pots
destination-pattern 3002
port 1/2 dial-peer voice 3 pots
destination-pattern 3003
port 1/3 dial-peer voice 4 pots
destination-pattern 3004
port 1/4
Because each dial peer has a different destination pattern configured, there is no backup available if the DS0 timeslot mapped to the dial peer is busy with another call.
However, the Cisco MC3810 supports the concept of hunt groups, in which you configure a group of dial peers on the same PBX with the same destination pattern. With a hunt group, if a call attempt is made to a dial peer on a specific DS0 timeslot, if that timeslot is busy, the Cisco MC3810 hunts for another timeslot on that channel until an available timeslot is found. In this case, each dial peer is configured using the same destination pattern of 3000, forming a dial pool to that destination pattern.
To provide specific dial peers in the pool with a preference over other dial peers, you can configure the preference order for each dial peer using the preference command. The following is an example of the dial-peer configuration with all dial peers having the same destination pattern, but different preference orders:
dial-peer voice 1 pots
destination pattern 3000
port 1/1
preference 0 dial-peer voice 2 pots
destination pattern 3000
port 1/2
preference 1 dial-peer voice 3 pots
destination pattern 3000
port 1/3
preference 2 dial-peer voice 4 pots
destination pattern 3000
port 1/4
preference 3
Note that when setting the preference order, the lower the preference number, the higher the priority. The highest priority is given to the dial peer with preference order 0.
You can also set the preference order on the network side, for voice network dial peers. However, you cannot mix the preference orders for POTS dial peers (local telephone devices) and voice-network peers (devices across the WAN backbone). You can set a separate preference order for each dial-peer type, but the preference order will not work on both at the same time. For example, you can configure preference order 0, 1, and 2 for voice telephony dial peers, and you can configure a separate preference order 0, 1, and 2 for the voice network dial peers, but the two preference orders are separate. The system only resolves the preference among dial peers of the same type; it does not resolve preferences between the two separate preference order lists.
The hunt group feature hunts for dial peers in the following order:
1. Dial peers are first hunted based on the priority set using the preference dial-peer command.
2. Dial peers are then hunted using the criteria of the longest number match. For example, if you have one dial peer set for 345.... and a second dial peer set for 3456789, the hunt group would first select the dial peer 3456789 because it has the longest match of the two dial peers.
3. Local POTS dial peers are hunted first before voice network peers.
4. Dial peers are then hunted in the order they were defined on the Cisco MC3810.
In most voice configurations, fixed-length dialing plans, in which all the dial-peer destination patterns have the same length, are sufficient because the telephone number strings are all the same length. However, in some voice network configuration, variable length dial plans are required, especially if the network crosses country boundaries and the telephone number strings are of different lengths.
By entering the "T" timer character in the destination pattern, the Cisco MC3810 can be configured to accept a fixed-length dial string, and then wait for additional dialed digits. For example, the following dial-peer configuration shows how the T character can be set to allow variable length dial strings.
dial peer voice 1 pots destination-pattern 2222T port 1/1
In this example, the Cisco MC3810 accepts the digits 2222, and then waits for an unspecified number of dialed digits. If digits continue to be entered before the inter-digit timeout expires, then the Cisco MC3810 will gather up to 31 additional digits. Once the inter-digit timeout expires, the Cisco MC3810 places the call. The inter-digit timeout is set by the timeouts inter-digit voice-port command.
The inter-digit timeout timer can be immediately terminated by entering the "#" digit. If the # character is entered while the Cisco MC3810 is waiting for the additional digits, the # character is treated as an end-dial accelerator. The # character is not treated as an actual digit in the destination pattern and is not sent as part of the dialed string across the network.
However, if the # character is entered before the Cisco MC3810 is waiting for the additional digits (meaning before the "T" character is entered in the destination pattern)< then the # character is treated as a dialed digit. For example, if a destination pattern is configured with the string 222...T, then the digits 2222####1234567 can be gathered, but the digits 2222###1234#67 cannot be gathered because the final # character is treated as a terminator.
The default value for the interdigit timeout is 1- seconds. If the duration is not changed, using the "T" timer adds 10 seconds to each call setup time because the call is not attempted until the timer expires (unless the # character is used as a terminator). Because of this dependency, if using variable length dial plans, the voice-port interdigit timeout should be reduced to reduce the call setup time.
This section provides the following Voice over Frame Relay configuration examples:
Figure 22 shows a configuration example for two Cisco MC3810 concentrators configured back-to-back, with Voice over Frame Relay configured for both concentrators. This setup is useful to test your Voice over Frame Relay configuration locally to make sure voice connections can be made locally before configuring Voice over Frame Relay across a larger network. Following the figure are the commands required to configure the Cisco MC3810 concentrators in this example.
no service pad no service udp-small-servers no service tcp-small-servers hostname Frame-top frame-relay switching interface Ethernet0 ip address 10.1.10.1 255.0.0.0 interface Serial0 point-to-point ip address 12.0.0.3 255.0.0.0 encapsulation frame-relay no fair-queue clock rate network-clock 2000000 dce terminal-timing enable frame-relay class fr1 frame-relay map ip 12.0.0.1 231 broadcast frame-relay interface-dlci 231 voice-encap 1600 frame-relay intf-type dce map-class frame-relay fr1 frame-relay adaptive-shaping becn frame-relay cir 64000 frame-relay bc 1000
router rip redistribute connected network 12.0.0.0 voice-port 1/1 dial-peer voice 1 pots destination-pattern 10 port 1/1 dial-peer voice 101 vofr destination-pattern 2. session target Serial0 231 end
interface Ethernet0 ip address 10.1.20.1 255.0.0.0 router rip redistribute connected network 12.0.0.0 interface Serial0 point-to-point ip address 12.0.0.1 255.0.0.0 encapsulation frame-relay bandwidth 2000000 frame-relay class fr1 frame-relay map ip 12.0.0.3 231 broadcast frame-relay interface-dlci 231 voice-encap 1600 map-class frame-relay fr1 frame-relay adaptive-shaping becn frame-relay cir 64000 frame-relay bc 1000 voice-port 1/1 dial-peer voice 1 pots destination-pattern 20 port 1/1 dial-peer voice 101 vofr destination-pattern 1. session target Serial0 231 end
The following is a configuration example for a Voice over Frame Relay network, including configuration for voice ports and dial peers. Figure 23 shows the configuration for one Cisco MC3810 at a central site connected to two Cisco MC3810 concentrators at different remote sites across a Frame Relay network. Following the figure are the commands required to configure the Cisco MC3810 concentrators in this example.
The following is the configuration for the central site Cisco MC3810 concentrator:
hostname central controller T1 0 framing esf linecode b8zs channel-group 1 timeslots 1-24 speed 64 interface Ethernet0 ip address 172.22.124.66 255.255.255.0 interface Serial 0:1 multipoint ip address 223.223.224.229 255.255.255.0 encapsulation frame-relay no fair-queue frame-relay traffic-shaping frame-relay interface-dlci 100 voice-encap 80 class fr1 frame-relay interface-dlci 200 voice-encap 160 class fr2 router igrp 1 network 172.22.0.0 network 223.223.224.0 no ip classless map-class frame-relay fr1 frame-relay adaptive-shaping becn frame-relay cir 64000 frame-relay bc 1000 map-class frame-relay fr2 frame-relay adaptive-shaping becn frame-relay cir 128000 frame-relay bc 1000 line con 0 exec-timeout 0 0 line aux 0 line vty 0 voice-port 1/1 voice-port 1/2 voice-port 1/3 voice-port 1/4 voice-port 1/5 voice-port 1/6 dial-peer voice 1 pots destination-pattern 3488801 port 1/1 dial-peer voice 2 pots destination-pattern 3488802 port 1/2 dial-peer voice 3 pots destination-pattern 3488803 port 1/3 dial-peer voice 4 pots destination-pattern 3488804 port 1/4 dial-peer voice 5 pots destination-pattern 3488805 port 1/5 dial-peer voice 6 pots destination-pattern 3488806 port 1/6 dial-peer voice 338 vofr destination-pattern 338.... session target Serial0:1 100 dial-peer voice 358 vofr destination-pattern 358.... session target Serial0:1 200 end
The following is the configuration for the Cisco MC3810 concentrator at Remote Site 1:
hostname remote1 controller T1 0 framing esf linecode b8zs channel-group 2 timeslots 1 speed 64 interface Ethernet0 ip address 172.22.125.66 255.255.255.0 interface Serial 0:2 multipoint ip address 223.223.224.227 255.255.255.0 encapsulation frame-relay no fair-queue frame-relay traffic-shaping frame-relay interface-dlci 100 voice-encap 80 class fr1 router igrp 1 network 172.22.0.0 network 223.223.224.0 no ip classless map-class frame-relay fr1 frame-relay cir 64000 frame-relay bc 1000 frame-relay adaptive-shaping becn line con 0 exec-timeout 0 0 line aux 0 line vty 0 voice-port 1/1 voice-port 1/2 voice-port 1/3 voice-port 1/4 voice-port 1/5 voice-port 1/6 dial-peer voice 1 pots destination-pattern 3388801 port 1/1 dial-peer voice 2 pots destination-pattern 3388802 port 1/2 dial-peer voice 3 pots destination-pattern 3388803 port 1/3 dial-peer voice 4 pots destination-pattern 3388804 port 1/4 dial-peer voice 5 pots destination-pattern 3388805 port 1/5 dial-peer voice 6 pots destination-pattern 3388806 port 1/6 dial-peer voice 2000 vofr destination-pattern 358.... session target Serial0:2 100 dial-peer voice 2001 vofr destination-pattern 348.... session target Serial0:2 100
The following is the configuration for the Cisco MC3810 concentrator at Remote Site 2:
hostname remote2 interface Ethernet0 ip address 172.22.126.66 255.255.255.0 interface Serial1 multipoint ip address 223.223.224.226 255.255.255.0 encapsulation frame-relay no fair-queue frame-relay traffic-shaping frame-relay interface-dlci 200 voice-encap 160 class fr1 clock rate 128000 router igrp 1 network 172.22.0.0 network 223.223.224.0 no ip classless map-class frame-relay fr1 frame-relay cir 128000 frame-relay bc 1000 frame-relay adaptive-shaping becn line con 0 exec-timeout 0 0 line aux 0 line vty 0 voice-port 1/1 voice-port 1/2 voice-port 1/3 voice-port 1/4 voice-port 1/5 voice-port 1/6 dial-peer voice 1 pots destination-pattern 3588801 port 1/1 dial-peer voice 2 pots destination-pattern 3588802 port 1/2 dial-peer voice 3 pots destination-pattern 3588803 port 1/3 dial-peer voice 4 pots destination-pattern 3588804 port 1/4 dial-peer voice 5 pots destination-pattern 3588805 port 1/5 dial-peer voice 6 pots destination-pattern 3588806 port 1/6 dial-peer voice 2000 vofr destination-pattern 348.... session target Serial1 200 dial-peer voice 2001 vofr destination-pattern 338.... session target Serial1 200 end
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