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Table Of Contents
Trunk Conditioning on the
Cisco MC3810Configuring a Voice Class to Define Trunk Conditioning Attributes
Applying Voice Class Signaling Attributes to the Voice Network Dial Peer
signal timing idle suppress-voice
Trunk Conditioning on the
Cisco MC3810
Feature Overview
Trunk conditioning on the Cisco MC3810 enables you to create a voice class, configure specific signaling attributes to the voice class, and then map the attributes in the voice class to either a Voice over Frame Relay, Voice over ATM, or a Voice over HDLC dial peer. Using the voice class, you can define the keepalive signaling packet interval and the signal pattern (ABCD) bit pattern for Cisco-trunk (private-line) calls.
Benefits
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Enables greater control over the signaling attributes for Cisco trunk (private line) calls sent over Frame Relay, Asynchronous Transfer Mode (ATM), or High-Level Data Link Control (HDLC) networks.
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Restrictions
The following restrictions and limitations apply to trunk conditioning on the Cisco MC3810:
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For information on configuring Cisco-trunk (private line) calls on the Cisco MC3810, see the Voice over Frame Relay Using FRF.11 and FRF.12 online feature guide for Cisco IOS Release 12.0(4)T.
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Supported Platforms
This feature is supported only on the Cisco MC3810.
Prerequisites
Before you can configure trunk conditioning, you must have already configured one of the following:
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For more information, see the online feature guide Voice over Frame Relay Using FRF.11 and FRF.12 for Cisco IOS Release 12.0(4)T.
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For more information, see the Voice, Video, and Home Applications Configuration Guide for Cisco IOS Release 12.0, or the Cisco MC3810 Multiservice Access Concentrator Software Configuration Guide.
Supported MIBs and RFCs
None
List of Terms and Acronyms
ABCD signaling—Four-bit telephony line signaling coding in which each letter of "ABCD" represents one of the four bits. This is often associated with CAS or Robbed-Bit signaling on a T1 or E1 telephony trunk.
AIS—Alarm Indication Signal
Cisco-trunk (private line) call—A Cisco-trunk (private line) call is established by the forced connection of a dynamic switched call. A Cisco-trunk call is established during configuration of the trunk and stays up for the duration of the configuration. It optionally provides a pass-through connection path to pass signaling information between the two telephony interfaces at either end of the connection.
CODEC—Coder-Decoder. (i) An integrated circuit device that typically uses pulse code modulation to transform analog signals into a digital bit stream and digital signals back into analog signals. (ii) In Voice over IP, Voice over Frame Relay, and Voice over ATM, a DSP software algorithm used to compress/decompress speech or audio signals.
DLCI—Data-link connection identifier.
Dial peer—An addressable call endpoint that contains configuration information including voice protocol, CODEC type, and telephone number associated with the call endpoint. There are five kinds of dial peers: POTS, VoIP, VoFR, VoATM, and VoHDLC.
DTMF—Dual tone multifrequency. Use of two simultaneous voice-band tones for dial (such as touch tone).
DTMF relay—Enables the generation of FRF.11 Annex A frames for a VoFR dial peer. The DSP generates Annex A frames instead of passing a DTMF tone through the network as a voice sample.
Dynamic switched call—A telephone call dynamically established across a packet data network based on a dialed telephone number. In the case of VoFR, a Cisco proprietary session protocol similar to Q.931 is used to achieve call switching and negotiation between calling endpoints. The proprietary session protocol runs over FRF.11-compliant subchannels.
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 analog E&M interface is an RJ-48 connector that allows connections to PBX trunk lines (tie lines). E&M is also available on E1 and T1 digital interfaces.
FRF—Frame Relay Forum. An association of corporate members consisting of vendors, carriers, users and consultants committed to the implementation of Frame Relay in accordance with national and international standards. Refer to the website at http://www.frforum.com.
FRF.11—Frame Relay Forum implementation agreement for Voice over Frame Relay (v1.0 May 1997). This specification defines multiplexed data, voice, fax, DTMF digit-relay and CAS/Robbed-bit signaling frame formats, but does not include call setup, routing or administration facilities. Refer to the website at http://www.frforum.com.
FRF.11 Annex C—See FRF.12.
FRF11-trunk—A point-to-point permanent voice connection (private line) conforming to the FRF.11 specification.
FRF.12—The FRF.12 Implementation Agreement (also known as FRF.11 Annex C) was developed to allow long data frames to be fragmented into smaller pieces and interleaved with real-time frames. In this way, real-time voice and non real-time data frames can be carried together on lower speed links without causing excessive delay to the real-time traffic.
FXO—Foreign Exchange Office. An FXO interface connects to the Public Switched Telephone Network's (PSTN) 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 or to a station interface on a PBX.
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.
MEL CAS—Mercury Exchange Limited (MEL) Channel Associated Signaling. A voice signaling protocol used primarily in the United Kingdom.
OOS—Out of Service state of the call or trunk.
PBX—Private Branch Exchange. Privately owned central switching office.
Permanent calls—Permanent calls are private line calls used for fixed point-to-point calls, connections between PBXs (E&M to E&M), or for remote telephone extensions (FXO to FXS).
POTS—Plain old telephone service. Basic telephone service supplying standard single line telephones, telephone lines, and access to the PSTN.
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.
Switched calls—Switched calls are normal telephone calls in which a user picks up a phone, hears dial tone, enters the destination phone number to reach the other phone. Switched calls can also be private line auto-ringdown (PLAR) calls, or tie-line calls for fixed point-to-point connections.
Tandem switching—The dynamic switching of voice calls between VoFR, VoATM, or VoHDLC PVCs and subchannels; also called tandeming. Tandem switching is often encountered in multi-hop VoFR call connection paths.
Trunk—Service that allows quasi-transparent connections between two PBXs, a PBX and a local extension, or some other combination of telephony interfaces with signaling passed transparently through the packet data network.
VoFR—Voice over Frame Relay.
VoFR dial peer—Dial peer connected via a Frame Relay network. VoFR peers point to specific VoFR devices.
Voice over Frame Relay—Voice over Frame Relay enables a router to carry voice traffic (for example, telephone calls and faxes) over a Frame Relay network. When sending voice traffic over Frame Relay, the voice traffic is segmented and encapsulated for transit across the Frame Relay network using FRF.12 encapsulation.
Voice over IP—Voice over IP enables a router to carry voice traffic (for example, telephone calls and faxes) over an IP network. In Voice over IP, the DSP segments the voice signal into frames, which are then coupled in groups of two and stored in voice packets. These voice packets are transported using IP in compliance with ITU-T specification H.323.
VoIP—Voice over IP.
Functional Description
When voice over packet calls are used to provide fixed point to point permanent connections (private line or tie-line) between two PBXs, fault indications are sent to the PBX so that if the permanent connection fails, the PBX is able to select an alternate path to route calls. This feature addresses analog telephony connections or digital T1/E1 using CAS/robbed-bit "ABCD" signaling. It does not cover CCS type signaling.
When carrying T1/E1 CAS/robbed-bit ABCD signaling in transparent pass-through mode for arbitrary, unknown or unsupported CAS/robbed-bit protocols, it is necessary to define explicit on-hook/idle patterns so that the DSP/signaling code can sense the idle call state and shut off the flow of voice packets when no active call is in progress. This provides an additional idle bandwidth saving mechanism for cases in which bandwidth saving using Voice Activity Detection (VAD) is not desired.
Configuration Tasks
This section describes how to configure a voice class to define trunk conditioning attributes for both Voice over Frame Relay and Voice over ATM. The following major tasks are described in the following sections:
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Configuring a Voice Class to Define Trunk Conditioning Attributes
In conjunction with the configuration for permanent connections (Cisco trunks and FRF.11 trunks), you can define a voice class and configure specific signaling attributes to the voice class, and then map the voice class to a dial peer.
To configure a voice class to define trunk conditioning attributes, including signaling attributes, use the following commands beginning in global configuration mode:
After you have created the voice class, assign it to a Voice over Frame Relay or Voice over ATM dial peer using the voice-class permanent dial-peer configuration command.
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Applying Voice Class Signaling Attributes to the Voice Network Dial Peer
After you have created the voice class, you must apply the voice class to the dial peer configuration. You can assign voice-class signaling attributes to Voice over Frame Relay, Voice over ATM, or Voice over HDLC dial peers. You cannot assign voice-class signaling attributes to POTS dial peers.
To apply voice-class signaling attributes to the voice network dial peer, use the following commands beginning in global configuration mode:
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Define a VoFR, VoATM, or VoHDLC 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 tag value identifies the dial peer and must be unique on the router. Do not duplicate a specific tag number.
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Assign to the dial peer the voice class that you created in the "Configuring a Voice Class to Define Trunk Conditioning Attributes" section.
Note
Configuration Example
The following example configures a voice class and then applies it to both a Voice over Frame Relay dial peer and a Voice over ATM dial peer:
router(config)# voice class permanent 10
router(config-class)# signal keepalive 10
router(config-class)# signal pattern idle receive 0101
router(config-class)# signal pattern idle transmit 0101
router(config-class)# signal timing idle suppress-voice 5
router(config-class)# signal pattern oos receive 0001
router(config-class)# signal pattern oos transmit 0001
router(config-class)# signal timing oos timeout 60
router(config-class)# signal timing oos restart 120
router(config-class)# signal timing oos suppress-voice 30
router(config)# dial peer voice vofr 10
router(config-dial-peer)# voice-class permanent 10
router(config)# dial peer voice voatm 20
router(config-dial-peer)# voice-class permanent 10Command Reference
The following new and modified commands are described in this section (modified commands are marked by an asterisk):
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signal keepalive
To configure the keepalive signaling packet interval for Cisco trunks and FRF.11 trunks, use the signal keepalive voice-class configuration command. Use the no form of this command to restore the default value.
signal keepalive number
no signal keepalive numberSyntax Description
number
Specifies the keepalive signaling packet interval in seconds. The valid range is from 1 to 65535 seconds.
Defaults
5 seconds
Command Modes
Voice-class configuration
Command History
Usage Guidelines
Before configuring the keepalive signaling interval, you must use the voice class permanent command in global configuration mode to create a voice class for the Cisco trunk or FRF.11 trunk. The voice class must then be assigned to a dial peer.
Examples
The following example, beginning in global configuration mode, sets the keepalive signaling interval to 3 seconds for voice class "10."
router(config)# voice class permanent 10router(config-class)# signal keepalive 3router(config-class)# exitrouter(config)# dial-peer voice 100 vofrrouter(config-dial-peer)# voice-class permanent 10Related Commands
signal pattern
To configure the ABCD bit pattern for Cisco trunks and FRF.11 trunks, use the signal pattern voice-class configuration command. Use the no form of this command to remove the signal pattern setting from the voice class.
signal pattern {idle receive | idle transmit | oos receive | oos transmit} WORD
no signal pattern {idle receive | idle transmit | oos receive | oos transmit} WORDSyntax Description
Defaults
No signal pattern is defined.
Command Modes
Voice-class configuration
Command History
Usage Guidelines
Before configuring the signaling pattern, you must use the voice class permanent command in global configuration mode to create a voice class for the Cisco trunk or FRF.11 trunk. The voice class must then be assigned to a dial peer.
This command must be entered twice. When you enter the command to specify the signaling pattern for the idle transmit state, you must reenter the command to specify the signaling pattern for the idle receive state.
The idle state of a call is normally based on both the transmit and receive idle patterns matching the signaling state in the signaling packets. If only one direction is configured (transmit or receive), the idle state will be detected based only on the direction that is configured. The out-of-service (OOS) transmit pattern is matched against the signaling state from the PBX (and transmitted to the network). This is used in conjunction with either the suppress-voice timing parameter or the suppress-all parameter.
The OOS receive pattern is the pattern sent to the PBX if the signal timing oos timeout timer expires during which no signaling packets are received from the network. The OOS receive pattern is not used for pattern matching against the signaling packets received from the network. The receive packets directly indicate an OOS condition by setting the AIS alarm indication bit in the packet.
To "busy out" a PBX if the network connection fails, set the OOS receive pattern to match the seized state (busy), then set the signal timing oos timeout value. When the timeout value expires and no signaling packets have been received, the router will send the OOS receive pattern to the PBX.
Use the busy seized pattern only if the PBX does not have a special pattern specifically intended to indicate an OOS state. If the PBX does have a specific OOS pattern, use that pattern instead.
Examples
The following example, beginning in global configuration mode, configures the signaling bit pattern for the idle receive and transmit states:
router(config)# voice class permanent 10 router(config-class)# signal keepalive 3 router(config-class)# signal pattern idle receive 0101 router(config-class)# signal pattern idle transmit 0101 router(config-class)# exitrouter(config)# dial-peer voice 100 vofrrouter(config-dial-peer)# voice-class permanent 10The following example, beginning in global configuration mode, configures the signaling bit pattern for the out-of-service receive and transmit states:
router(config)# voice class permanent 10 router(config-class)# signal keepalive 3 router(config-class)# signal pattern oos receive 0001 router(config-class)# signal pattern oos transmit 0001router(config-class)# exitrouter(config)# dial-peer voice 100 vofrrouter(config-dial-peer)# voice-class permanent 10
Related Commands
signal timing idle suppress-voice
To configure the signal timing parameter for the idle state of the call, use the signal timing idle suppress-voice voice-class configuration command. Use the no form of this command to restore the default value.
signal timing idle suppress-voice seconds
no signal timing idle suppress-voice secondsSyntax Description
seconds
Duration of the idle state in seconds before the voice traffic is stopped. The valid range is from 0 to 65535.
Defaults
No signal timing idle suppress-voice timer is configured.
Command Modes
Voice-class configuration
Command History
Usage Guidelines
Before configuring the signal timing idle suppress-voice timer, you must use the voice class permanent command in global configuration mode to create a voice class for the Cisco trunk or FRF.11 trunk. The voice class must then be assigned to a dial peer.
This command is used when the signal-type command is set to transparent in the dial peer for the Cisco trunk or FRF.11 trunk connection. The Cisco MC3810 stops sending voice packets when the timer expires. Signaling packets are still sent.
Examples
The following example, beginning in global configuration mode, sets the signal timing idle suppress-voice timer to 5 for the idle state on voice class "10."
router(config)# voice class permanent 10router(config-class)# signal keepalive 3 router(config-class)# signal pattern idle receive 0101 router(config-class)# signal pattern idle transmit 0101 router(config-class)# signal timing idle suppress-voice 5router(config-class)# exitrouter(config)# dial-peer voice 100 vofrrouter(config-dial-peer)# voice-class permanent 10router(config-dial-peer)# signal-type transparent
Related Commands
signal timing oos
To configure the signal timing parameter for the out-of-service (OOS) state of the call, use the signal timing oos voice-class configuration command. Use the no form of this command to restore the default value.
signal timing oos {restart | slave-standby | suppress-all | suppress-voice | timeout} seconds
no signal timing oos {restart | slave-standby | suppress-all | suppress-voice | timeout} secondsSyntax Description
Defaults
No signal timing OOS pattern parameters are configured.
Command Modes
Voice-class configuration
Command History
Usage Guidelines
Before configuring signal timing OOS parameters, you must use the voice class permanent command in global configuration mode to create a voice class for the Cisco trunk or FRF.11 trunk. The voice class must then be assigned to a dial peer.
You can enter several values for this command. However, the suppress-all and suppress-voice options are mutually exclusive.
Examples
The following example, beginning in global configuration mode, configures the signal timeout parameter for the out-of-service state on voice class "10." The signal timing oos timeout command is set to 60 seconds.
router(config)# voice-class permanent 10router(config-class)# signal-keepalive 3 router(config-class)# signal pattern oos receive 0001 router(config-class)# signal pattern oos transmit 0001 router(config-class)# signal timing oos timeout 60router(config-class)# exitrouter(config)# dial-peer voice 100 vofrrouter(config-dial-peer)# voice-class permanent 10
Related Commands
signal-type
To set the signaling type to be used when connecting to a dial peer, use the signal-type command from dial-peer configuration mode. To return to the default signal-type, use the no form of this command.
Cisco 2600 series and 3600 series Routers
signal-type {cas | ext-signal}
no signal-typeCisco MC3810
signal-type {cas | cept | ext-signal | transparent}
no signal-typeSyntax Description
Defaults
cas
Command Modes
Dial-peer configuration
Command History
12.0(3)XG
This command was first introduced.
12.0(4)T
Support was added for the Cisco 7200 series routers.
Usage Guidelines
This command applies to VoFR, VoATM, and VoHDLC dial peers. It is used with permanent connections only (Cisco trunks and FRF.11 trunks), not with switched calls.
This command is used to inform the local telephony interface of the type of signaling it should expect to receive from the far-end dial peer. To turn signaling off at this dial peer, select the ext-signal option. If signaling is turned off and there are no external signaling channels, a "hot" line exists, enabling this dial peer to connect to anything at the far end.
On the Cisco 2600 series and 3600 series routers, there are only two possible settings for trunks (VoFR dial peers only):
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When you connect an FXS to another FXS, or if you have anything other than an FXS/FXO or E&M/E&M pair, the appropriate signaling type on Cisco 2600 series and 3600 series routers is ext-signal (disabled).
On the Cisco MC3810, there are two additional signal-type settings:
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If you have a digital E1 connection at the remote end that is running cept/MELCAS signaling and you then trunk that across to an analog port, you should make sure that you configure both ends for the cept signal-type.
If you have a T1 or E1 connection at both ends and the T1/E1 is running a signaling protocol that is neither EIA-464nor cept/MELCAS, you might want to configure the signal-type for the transparent option in order to pass through the signaling.
Examples
The following example shows how to disable signaling on a Cisco 2600 series or 3600 series router or on a Cisco MC3810 multiservice access concentrator for VoFR dial peer 200, starting from global configuration mode:
router(config)# dial-peer voice 200 vofrrouter(config-dial-peer)# signal-type ext-signalrouter(config-dial-peer)#
Related Commands
voice class permanent
To create a voice class for a Cisco trunk or FRF.11 trunk, use the voice class permanent global configuration command. Use the no form of this command to delete the voice class.
voice class permanent tag
no voice class permanent tagSyntax Description
tag
Specifies the unique tag number you assign to the permanent voice class. The valid range for this tag is 1 to 10000. The tag number must be unique on the router.
Defaults
No voice class is configured.
Command Modes
Global configuration
Command History
Usage Guidelines
This command can be used for VoFR, VoATM, and VoHDLC trunks.
Note
Examples
The following example shows how to create a permanent voice class starting from global configuration mode:
router(config)# voice class permanent 10router(config-class)#
Related Commands
voice-class permanent
To assign a previously-configured voice class for a Cisco trunk or FRF.11 trunk to a dial peer, use the voice-class permanent dial-peer configuration command. Use the no form of this command to remove the voice-class assignment from the dial peer.
voice-class permanent tag
no voice-class permanent tagSyntax Description
Defaults
This command has no default.
Command Modes
Dial-peer configuration
Command History
Usage Guidelines
Note
Examples
The following example shows how to configure a permanent voice class starting from global configuration mode, configure parameters for that voice class, and then assign the voice class to a dial peer:
router(config)# voice class permanent 10router(config-class)# signal keepalive 3router(config-class)# exitrouter(config)# dial-peer voice 100 vofrrouter(config-dial-peer)# voice-class permanent 10
Related Commands
