Table Of Contents
Restrictions for Voice Call Tuning
Information About Voice Call Tuning
How to Verify Voice Call Tuning Functionality
Configuration Examples for Voice Call Tuning
Voice Call Tuning
The Voice Call Tuning feature monitors the interface between Cisco IOS software and a system's digital signaling processors (DSPs) in real time and reports status on the following: packet flow, DSP state, echo-cancellation state, and jitter state. The feature also allows you to manipulate echo-cancellation and jitter-buffer parameters in real time.
The feature is part of the standards product and is supported under normal Cisco Technical Assistance Center (TAC) procedures. No new code is required. It is backward compatible with older versions of Cisco IOS software, Cisco VCWare, and Cisco DSPWare, and accommodates the Conexant family of products.
Feature Specifications for Voice Call Tuning
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 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:
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:
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.
Contents
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Restrictions for Voice Call Tuning
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Information About Voice Call Tuning
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How to Verify Voice Call Tuning Functionality
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Configuration Examples for Voice Call Tuning
Restrictions for Voice Call Tuning
If you wish to use this feature on a Cisco AS5300 platform, refer to the Combined Version Release Notes for Cisco VCWare on Cisco AS5300 Universal Access Servers/Voice Gateways for more information about which Cisco VCWare to use with this feature.
Information About Voice Call Tuning
To configure the Voice Call Tuning feature, you must understand the following concepts:
Packet-Flow Detection
The analog signal from the telephone is digitized into pulse code modulation (PCM) signals by the voice coder-decoder (codec). The PCM samples are then passed to the compression algorithm which compresses the voice into a packet format for transmission across the WAN. On the far side of the cloud the exact same functions are performed in reverse order.
Depending on how the network is configured, the router or gateway can perform both the codec and compression functions or only one of them. For example, if an analog voice system is used, then the router or gateway performs the CODEC function and the compression function.
The Voice Call Tuning feature allows you to determine whether packets are flowing in each direction while a call is in progress.
DSP State
The Voice Call Tuning feature allows you to check whether the DSP servicing an active call is functioning properly. Explicit configuration of a periodic ping message with both the period and timeout parameters configurable catches DSPs that are in a hung state as soon as possible. A failure can then signal this event to the console log or as a triggering event to a logging functionality. The DSP can also send periodic informational messages like jitter measures, echo canceller measures, and alarms to alert you if there is an impending problem.
Echo-Cancellation State
Echo is the sound of your own voice reverberating in the telephone receiver while you are talking. When timed properly, echo is not a problem in the conversation; however, if the echo interval exceeds approximately 25 ms, it can be distracting to the speaker. Echo is controlled by ECs. By design, ECs are limited by the total amount of time they wait for the reflected speech to be received, which is known as an echo tail. The echo tail is normally 32 ms.
In the traditional telephony network, echo is generally caused by an impedance mismatch when the four-wire network is converted to the two-wire local loop. Echo cancellation is required because of packet network latency.
Echo cancellation is implemented in DSP firmware on the gateways and is independent of other functions implemented in the DSP (the DSP protocol and compression algorithm). In voice packet-based networks, ECs are built into the low-bit-rate codecs and are operated on each DSP
This feature gives you the ability to change echo canceller parameters while a call is in progress. Audible effects are immediately noticed, aiding in problem determination and resolution. You have the ability to change the echo canceller parameters (tail length and ERL threshold) in the field.
Jitter-Buffer Parameters
Jitter is a variation in the delay of received packets. At the sending side, packets are sent in a continuous stream with the packets being spaced evenly apart. Due to network congestion, improper queuing, or configuration errors, this steady stream can become lumpy, or the delay between each packet can vary instead of remaining constant.
This feature gives you the ability to change jitter-buffer parameters while a call is in progress. Audible effects are immediately noticed, aiding in problem determination and resolution. You have the ability to change the jitter buffer parameters (delay, size, fixed state or adaptive state) in the field.
How to Verify Voice Call Tuning Functionality
There are no configuration tasks for this feature. However, you can verify that the Voice Call Tuning feature is operating on your system by performing the following tasks:
Step 1
Use the show vfc version command to show the version of the software that resides on your voice feature card (VFC). This command shows information in the output of the
show vfc slot version vcware and show vfc slot version dspware commands that indicates whether the Cisco VCWare or DSPWare is compatible with the Cisco IOS image.Step 2
Use the show voice call command to show the real-time call status for voice ports, including packet flow indication, DSP state, echo canceller state, and jitter state.
Step 3
Use the test call id command to manipulate echo canceller and jitter-buffer parameters in real time. You can use this command with the extended echo canceller, which allows you to configure the voice card in a router individually, or with the standard echo canceller, which allows you to configure the router as a whole. Messages are visible in the command output when either an extended-only or a standard-only echo cancellation is requested:
Extended echo canceller not active for CallID callIDBasic echo canceller not active for CallID callIDConfiguration Examples for Voice Call Tuning
There are no specific configuration examples for the Voice Call Tuning feature, but you can verify that the Voice Call Tuning feature is operating on your system by performing the following tasks:
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Use the show vfc version command to show the version of the software that resides on your voice feature card (VFC). This command was modified to include new information in the output of the
show vfc slot version vcware and show vfc slot version dspware commands for the Voice Call Tuning feature. Messages are output if the Cisco VCWare or DSPWare is not compatible with the Cisco IOS image. The new information is advisory only, so there is no action taken if the software is compatible or incompatible.Cisco IOS Release 12.2(13)T adds new information to the output of the show vfc slot version vcware and show vfc slot version dspware commands. Messages are output if the Cisco VCWare or DSPWare is not compatible with the Cisco IOS image. The new information is advisory only, so there is no action taken if the software is compatible or incompatible.
If the versions detected fall within the defined criteria and are compatible, nothing is output at bootup time. A confirmation line is output when the show vfc version vcware and show vfc version dspware commands are used:
Router# show vfc 1 version vcwareVoice Feature Card in Slot 1:VCWare Version : 7.35ROM Monitor Version: 1.3DSPWare Version : 3.4.46LTechnology : C549VCWare/DSPWare version compatibility OK•
Use the show voice call command to show the real-time call status for voice ports, including packet flow indication, DSP state, echo canceller state, and jitter state. This command was modified with the status, call-id, and sample sample-period command options for the Voice Call Tuning feature. This command is available on all voice platforms.
Using the call-id argument is a generic means to identify active calls. If the call-id argument is omitted, the enquiry will show all active voice calls. In the following example, a list of all active calls with relevant identifying information is shown:
Router# show voice call statusCallID CID ccVdb Port DSP/Ch Called # Codec Dial-peers0x3 11D4 0x62972834 1/0/0 1/1 10001 g711ulaw 1/20x4 11D4 0x62973AD0 1/0/1 2/1 *10001 g711ulaw 2/10xA 11DB 0x62FE9D68 1/1/0 3/1 *2692 g729r8 0/26922 active calls found•
Use the test call id command to manipulate the echo canceller and jitter buffer parameters in real time. You can use this command with the extended echo canceller, which allows you to configure the voice card in a router individually, or with the standard echo canceller, in which the configuration occurs implicitly on the router.
The following example shows query output from a Cisco AS5350 universal gateway using the NextPort version of the standard echo canceller:
Router# test call id 99 ?echo-canceller test echo canceller on an active voice callplayout-delay test playout-delay parametersAdditional References
For additional information related to the Voice Call Tuning feature, see the following sections:
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MIBs
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RFCs
Related Documents
Standards
Standards TitleNo new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
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MIBs
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:
RFCs
RFCs TitleNo new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.
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Technical Assistance
Command Reference
This section documents modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.2 T command reference publications.
show vfc version
To show the version of the software that resides on a voice feature card (VFC), use the show vfc version command in privileged or user EXEC mode.
show vfc slot version {dspware | vcware}
Syntax Description
slot
Sot in which the VFC is installed. Valid values range from 0 to 2.
dspware
Specifies the DSPWare version.
vcware
Specifies the Cisco VCWare version.
Command Modes
Privileged or user EXEC
Command History
Usage Guidelines
Messages are output if the Cisco VCWare or DSPWare is not compatible with the Cisco IOS image. The new information is advisory only. You need take no action if the software is incompatible.
Examples
If the versions detected fall within the defined criteria and are compatible, nothing is output at bootup time. A confirmation line is output when the show vfc version vcware and show vfc version dspware commands are used:
Router# show vfc 1 version vcwareVoice Feature Card in Slot 1:VCWare Version : 7.35ROM Monitor Version: 1.3DSPWare Version : 3.4.46LTechnology : C549VCWare/DSPWare version compatibility OKRouter# show vfc 1 version dspwareDSPWare version in VFC slot 1 is 3.4.46LVCWare/DSPWare version compatibility OKIf the found versions are out of range or otherwise mismatched, a representative message is output when you boot up the router or is appended to the output of the commands. Other than the output of these messages, the version check has no other effect, and the software functions normally. The following example shows a found version that is out of range or mismatched at bootup:
...Firmware version mismatch for bundle AS5300 VCWare- version found (6.04) is lower than minimum required (7.35)Firmware version mismatch for bundle AS5300 C549- version found (3.3.10L) is lower than minimum required (3.4.46L)If you were to enter an explicit request and the software was incompatible, the following appears:
Router# show vfc 1 version vcwareVoice Feature Card in Slot 1:VCWare Version : 6.04ROM Monitor Version: 1.3DSPWare Version : 3.3.10LTechnology : C549Firmware version mismatch for bundle AS5300 VCWare- version found (6.04) is lower than minimum required (7.14)Firmware version mismatch for bundle AS5300 C549- version found (3.3.10L) is lower than minimum required (3.4.26L)Router# show vfc 1 version dspwareDSPWare version in VFC slot 1 is 3.3.10LFirmware version mismatch for bundle AS5300 VCWare- version found (6.04) is lower than minimum required (7.14)Firmware version mismatch for bundle AS5300 C549- version found (3.3.10L) is lower than minimum required (3.4.26L)Table 1 Describes significant fields shown in the command output for the show vfc version vcware command with compatible firmware.
Table 2 shows output field descriptions for the show vfc version dspware command with compatible firmware.
Related Commands
show voice call
To show the real-time call status for voice ports, including packet flow indication, DSP state, echo canceller state, and jitter state, use the show voice call command in either user EXEC or privileged EXEC mode.
Cisco 1700 Series and Cisco 7750 with Analog Voice Ports
show voice call [slot/port | summary call-id | status] [sample sample-period]
Cisco 2600, Cisco 3600, and Cisco 3700 Series with Analog Voice Ports
show voice call [slot/subunit/port | summary call-id | status] [sample sample-period]
Cisco 2600, Cisco 3600, and Cisco 3700 Series with Digital Voice Ports (with T1 Packet Voice Trunk Network Modules)
show voice call [slot/port:ds0-group | summary call-id | status] [sample sample-period]
Cisco 7200 and Cisco 7500 Series with Digital Voice Ports
show voice call [slot/port:ds0-group | summary call-id | status] [sample sample-period]
Cisco 827 with Analog Voice Ports
show voice call [slot/port | summary call-id | status] [sample sample-period]
Cisco AS5300, Cisco AS5350, Cisco AS5400, Cisco AS5800, and Cisco AS5850 with Analog Voice Ports
show voice call [slot/port:ds0-group | summary call-id | status] [sample sample-period]
Cisco CVA122 with Analog Voice Ports
show voice call [slot/subunit/port | summary call-id | status] [sample sample-period]
Cisco MC3810 with Analog Voice Ports
show voice call [slot/port | summary call-id | status] [sample sample-period]
Cisco MC3810 with Digital Voice Ports
show voice call [slot:ds0-group | summary call-id | status] [sample sample-period]
Cisco uBR92x with Analog Voice Ports
show voice call [slot/subunit/port | summary call-id | status] [sample sample-period]
Cisco VG200 with Analog Voice Ports
show voice call [slot/subunit/port | summary call-id | status] [sample sample-period]
Cisco VG200 with Digital Voice Ports
show voice call [slot/port:ds0-group | summary call-id | status] [sample sample-period]
For the Cisco 1700 Series and Cisco 7750 with Analog Voice Ports:
For Cisco 2600, Cisco 3600, and Cisco 3700 Series with Analog Voice Ports:
For Cisco 2600, Cisco 3600, and Cisco Series with Digital Voice Ports:
For the Cisco 7200 Series with Digital Voice Ports:
For the Cisco AS5300 Series with Digital Voice Ports
Note
The Voice Call Tuning feature is not supported on the Cisco AS5300.:
For the Cisco AS5350 Series with Digital Voice Ports:
For the Cisco AS5400 Series with Digital Voice Ports:
For the Cisco AS5800 Series with Digital Voice Ports:
For the Cisco CVA122 with Digital Voice Ports:
For the Cisco MC3810 with Analog Voice Ports:
For the Cisco MC3810 with Digital Voice Ports:
For the Cisco uBR92x with Analog Voice Ports:
For the Cisco VG200 with Analog Voice Ports:
Command Modes
User EXEC or privileged EXEC
Command History
Usage Guidelines
This command applies to Voice over Frame Relay, Voice over ATM, and Voice over IP.
This command shows call-processing and protocol state-machine information for a voice port, if it is available. It also shows information on the DSP channel associated with the voice port, if it is available. All real-time information in the DSP channel, such as jitter and buffer overrun for example, is queried to the DSP channel, and asynchronous responses are returned to the host side.
If no call is active on a voice port, the show voice call summary command displays only the VPM (shutdown) state. If a call is active on a voice port, the VTSPS state is shown. For an on-net call or a local call without local-bypass (not cross-connected), the CODEC and VAD fields are displayed. For an off-net call or a local call with local-bypass, the CODEC and VAD fields are not displayed.
Note
Only one call may be queried at a time. If you attempt queries from different ports (console and Telnet), and if a query is in progress on another port, the system requests that you wait for completion of that query. You can query any call from anywhere at anytime except during the sample interval for an enquiry already in progress.
CODEC and VAD are not displayed by the show voice call command because this information is in the summary display.
The show voice call command provides the status at these levels of the call handling module:
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Tandem switch
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End-to-end call manager
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Call processing state machine
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Protocol state machine
If you use the show voice call status command by itself, an immediate list of all the active calls is shown. You can use the call-id argument to request that the digital signal processor (DSP) associated with the call-id be queried for run-time statistics twice, once immediately and a second time after sample sample-period seconds.
The sample sample-period is the number of seconds over which the status is to be determined, ranging from 1 to 30 seconds. If sample sample-period is omitted, a default of 10 seconds is used. The results of the run-time statistic queries are then analyzed and presented in a one-line summary format.
When a call terminates during the specified sample period, the following output message is returned:
CallID call id cannot be queriedCallID call id second sample responses unavailableWhen using the test call id command, you must specify a call ID. The call ID is obtained by using the show voice call status command. The following is an example of how to obtain the call ID parameter that will be the value used in the call-id argument. The first parameter displayed in the output shows the call ID.
Note
You should not use the 0x prefix in the call-id argument when you enter the resulting call ID in the test call status command.
On a router that supports large numbers of active calls, the | (pipe) option can be used. The following keywords can be used to reduce and select the output:

