Table Of Contents
IP SLAs—Analyzing VoIP Service Levels Using the Call Setup Operation
Contents
Prerequisites for the IP SLAs VoIP Call Setup Monitoring Operation
Information About the IP SLAs VoIP Call Setup Monitoring Operation
IP SLAs VoIP Call Setup Monitoring Using H.323 or SIP
How to Configure the IP SLAs VoIP Call Setup Monitoring Operation
Configuring the Originating Gateway
Prerequisites
Troubleshooting Tips
What to Do Next
Configuring the Terminating Gateway Using the IP SLAs VoIP Responder Application
Prerequisites
Configuration Examples for the IP SLAs VoIP Call Setup Monitoring Operation
Configuring the Originating Gateway: Example
Configuring the Terminating Gateway: Example
Where to Go Next
Additional References
Related Documents
Standards
MIBs
RFCs
Technical Assistance
Feature Information for the IP SLAs VoIP Call Setup Operation
IP SLAs—Analyzing VoIP Service Levels Using the Call Setup Operation
First Published: August 14, 2006
Last Updated: July 31, 2008
The Cisco IOS IP Service Level Agreements (SLAs) VoIP Call Setup (Post-Dial Delay) Monitoring feature provides the ability to measure your network's response time for setting up a Voice over IP (VoIP) call. This document describes how to use the IP SLAs VoIP call setup operation to monitor the call setup performance of your VoIP network.
When using either H.323 or Session Initiation Protocol (SIP) , the IP SLAs VoIP call setup operation can measure the total time from when an originating gateway sends a call message (containing a call number) to when the originating gateway receives a message from the terminating gateway (destination) indicating that either the called number rang or the called party answered the call.
Finding Feature Information in This Module
Your Cisco IOS software release may not support all of the features documented in this module. To reach links to specific feature documentation in this module and to see a list of the releases in which each feature is supported, use the "Feature Information for the IP SLAs VoIP Call Setup Operation" section.
Finding Support Information for Platforms and Cisco IOS and Catalyst OS Software Images
Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
•
Prerequisites for the IP SLAs VoIP Call Setup Monitoring Operation
•
Information About the IP SLAs VoIP Call Setup Monitoring Operation
•
How to Configure the IP SLAs VoIP Call Setup Monitoring Operation
•
Configuration Examples for the IP SLAs VoIP Call Setup Monitoring Operation
•
Where to Go Next
•
Additional References
•
Feature Information for the IP SLAs VoIP Call Setup Operation
Prerequisites for the IP SLAs VoIP Call Setup Monitoring Operation
In order to use the IP SLAs VoIP call setup functionality, your Cisco IOS software image must support the IP SLAs VoIP test-call application and IP SLAs VoIP Responder application. To determine if your Cisco IOS software image is configured with these applications, use the show call application voice command in EXEC mode.
Note
The IP SLAs VoIP Responder application is different from the IP SLAs Responder (which is configured using the ip sla responder command in global configuration mode).
Information About the IP SLAs VoIP Call Setup Monitoring Operation
To configure an IP SLAs VoIP call setup operation, you should understand the following concept:
•
IP SLAs VoIP Call Setup Monitoring Using H.323 or SIP
IP SLAs VoIP Call Setup Monitoring Using H.323 or SIP
The Cisco IOS IP SLAs VoIP Call Setup Monitoring feature provides the ability to measure your network's response time for setting up a Voice over IP (VoIP) call. Prior to configuring the IP SLAs VoIP call setup operation, you must enable the IP SLAs VoIP test-call application on the originating gateway (source). With the IP SLAs VoIP test-call application enabled, H.323 or Session Initiation Protocol (SIP) call messages can be sent to and received by the originating and terminating gateways. The configuration for the IP SLAs VoIP call setup operation is essentially the same for both protocols.
When using either H.323 or SIP, the IP SLAs VoIP call setup operation can measure the total time from when an originating gateway sends a call message (containing a call number) to when the originating gateway receives a message from the terminating gateway (destination) indicating that either the called number rang or the called party answered the call. As with all Cisco IOS IP SLAs operations, you can configure the VoIP call setup operation to repeat at specified time intervals, for a specified number of repetitions, and over a specified duration of time.

Note
If a gatekeeper (GK) or directory gatekeeper (DGK) is involved in the H.323 call signaling, additional messages are sent and received between the originating and terminating gateways before the call message (containing a call number) is actually sent. The additional time required for these messages is included in the IP SLAs VoIP call setup response time measurement. Likewise, if a proxy server or redirection server is involved in the SIP call signaling, any additional time required for messages to be sent and received (prior to sending the call message) is included in the VoIP call setup response time measurement.
A plain old telephone service (POTS) IP phone can be set up at the terminating gateway to respond to an IP SLAs VoIP call setup test call. As a convenient alternative to an actual IP phone, you can enable the IP SLAs VoIP Responder application in the terminating gateway. The IP SLAs VoIP Responder application will respond to incoming call setup messages from the originating gateway using H.323 or SIP.
Note
The IP SLAs VoIP Responder application is different from the IP SLAs Responder (which is configured using the ip sla responder command in global configuration mode).
How to Configure the IP SLAs VoIP Call Setup Monitoring Operation
This section contains the following tasks:
•
Configuring the Originating Gateway
•
Configuring the Terminating Gateway Using the IP SLAs VoIP Responder Application
Configuring the Originating Gateway
Perform this task on the originating gateway (source) in order to start the IP SLAs VoIP test-call application, set up the dial peer to route the test call, define the VoIP call setup operation, and schedule the VoIP call setup operation. The required configuration for setting up the dial peer will vary slightly depending on whether you are using H.323 or SIP.
Prerequisites
In order to use the IP SLAs VoIP call setup functionality, your Cisco IOS software image must support the IP SLAs VoIP test-call application and IP SLAs VoIP Responder application. To determine if your Cisco IOS software image is configured with these applications, use the show call application voice command in EXEC mode.
Note
The IP SLAs VoIP Responder application is different from the IP SLAs Responder (which is configured using the ip sla responder command in global configuration mode).
SUMMARY STEPS
1.
enable
2.
show call application voice [name | summary]
3.
call application session start instance-name [application-name]
4.
configure terminal
5.
dial-peer voice tag voip
6.
destination-pattern [+] string [T]
7.
session target {ipv4:destination-address | dns:[$s$. | $d$. | $e$. | $u$.] host-name | enum:table-num | loopback:rtp | ras | sip-server}
8.
session protocol sipv2
9.
exit
10.
ip sla operation-number
11.
voip delay post-dial [detect-point {alert-ringing | connect-ok}] destination tag
12.
history buckets-kept size
13.
history distributions-of-statistics-kept size
14.
history enhanced [interval seconds] [buckets number-of-buckets]
15.
history filter {none | all | overThreshold | failures}
16.
frequency seconds
17.
history hours-of-statistics-kept hours
18.
history lives-kept lives
19.
owner owner-id
20.
history statistics-distribution-interval milliseconds
21.
tag text
22.
threshold milliseconds
23.
timeout milliseconds
24.
exit
25.
ip sla schedule operation-number [life {forever | seconds}] [start-time {hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss] [ageout seconds] [recurring]
26.
exit
27.
show ip sla configuration [operation-number]
DETAILED STEPS
| |
Command or Action
|
Purpose
|
Step 1
|
enable
Example:
Router> enable
|
Enables privileged EXEC mode.
• Enter your password if prompted.
|
Step 2
|
show call application voice [name | summary]
Example:
Router# show call application voice summary
NAME DESCRIPTION
...
ipsla-testcall Basic app to place a simple
call
ipsla-responder Basic app to respond to a
simple call
...
TCL Script Version 2.0 supported.
Call Treatment Action Application - Version 1.
|
(Optional) Displays information about configured voice applications.
• If the summary keyword is entered, the command output displays a one-line summary about each configured voice application.
• If the Cisco IOS IP SLAs VoIP test-call application is configured on the currently loaded Cisco IOS software image, the ipsla-testcall name is displayed.
|
Step 3
|
call application session start instance-name
[application-name]
Example:
Router# call application session start
ipsla-testcall ipsla-testcall
|
Starts a new session of the Cisco IOS IP SLAs VoIP test-call application.
|
Step 4
|
configure terminal
Example:
Router# configure terminal
|
Enters global configuration mode.
|
Step 5
|
dial-peer voice tag voip
Example:
Router(config)# dial-peer voice 6789 voip
|
Defines a particular dial peer, specifies the method of voice encapsulation, and enters dial-peer configuration mode.
• The tag argument consists of one or more digits identifying the dial peer. Range is from 1 to 2147483647.
• The voip keyword indicates a VoIP dial peer using voice encapsulation on an IP network.
|
Step 6
|
destination-pattern [+] string [T]
Example:
Router(config-dial-peer)# destination-pattern
6789
|
Specifies either the prefix or the full E.164 telephone number to be used for a dial peer.
|
Step 7
|
session target {ipv4:destination-address |
dns:[$s$. | $d$. | $e$. | $u$.] host-name |
enum:table-num | loopback:rtp | ras |
sip-server}
Example:
Router(config-dial-peer)# session target
ipv4:172.29.129.123
|
Designates a network-specific address to receive calls from a VoIP dial peer.
|
Step 8
|
session protocol sipv2
Example:
Router(config-dial-peer)# session protocol
sipv2
|
(Optional) Specifies SIP as the session protocol for the VoIP dial peer.
Note Perform this step only if configuring a SIP call.
|
Step 9
|
exit
Example:
Router(config-dial-peer)# exit
|
Exits dial-peer configuration mode and returns to global configuration mode.
|
Step 10
|
ip sla operation-number
Example:
Router(config)# ip sla 10
|
Begins configuration for an IP SLAs operation and enters IP SLA configuration mode.
|
Step 11
|
voip delay post-dial [detect-point
{alert-ringing | connect-ok}] destination tag
Example:
Router(config-ip-sla)# voip delay post-dial
detect-point alert-ringing destination 6789
|
Enters IP SLA VoIP configuration mode and configures the operation as a VoIP call setup (post-dial delay) operation that will generate VoIP call setup response time measurements.
|
Step 12
|
history buckets-kept size
Example:
Router(config-ip-sla-voip)# history
buckets-kept 25
|
(Optional) Sets the number of history buckets that are kept during the lifetime of an IP SLAs operation.
|
Step 13
|
history distributions-of-statistics-kept size
Example:
Router(config-ip-sla-voip)# history
distributions-of-statistics-kept 5
|
(Optional) Sets the number of statistics distributions kept per hop during an IP SLAs operation.
|
Step 14
|
history enhanced [interval seconds] [buckets
number-of-buckets]
Example:
Router(config-ip-sla-voip)# history enhanced
interval 900 buckets 100
|
(Optional) Enables enhanced history gathering for an IP SLAs operation.
|
Step 15
|
history filter {none | all | overThreshold |
failures}
Example:
Router(config-ip-sla-voip)# history filter
failures
|
(Optional) Defines the type of information kept in the history table for an IP SLAs operation.
|
Step 16
|
frequency seconds
Example:
Router(config-ip-sla-voip)# frequency 30
|
(Optional) Sets the rate at which a specified IP SLAs operation repeats.
|
Step 17
|
history hours-of-statistics-kept hours
Example:
Router(config-ip-sla-voip)# history
hours-of-statistics-kept 4
|
(Optional) Sets the number of hours for which statistics are maintained for an IP SLAs operation.
|
Step 18
|
history lives-kept lives
Example:
Router(config-ip-sla-voip)# history lives-kept
5
|
(Optional) Sets the number of lives maintained in the history table for an IP SLAs operation.
|
Step 19
|
owner owner-id
Example:
Router(config-ip-sla-voip)# owner admin
|
(Optional) Configures the Simple Network Management Protocol (SNMP) owner of an IP SLAs operation.
|
Step 20
|
history statistics-distribution-interval
milliseconds
Example:
Router(config-ip-sla-voip)# history
statistics-distribution-interval 10
|
(Optional) Sets the time interval for each statistics distribution kept for an IP SLAs operation.
|
Step 21
|
tag text
Example:
Router(config-ip-sla-voip)# tag
TelnetPollServer1
|
(Optional) Creates a user-specified identifier for an IP SLAs operation.
|
Step 22
|
threshold milliseconds
Example:
Router(config-ip-sla-voip)# threshold 10000
|
(Optional) Sets the upper threshold value for calculating network monitoring statistics created by an IP SLAs operation.
|
Step 23
|
timeout milliseconds
Example:
Router(config-ip-sla-voip)# timeout 10000
|
(Optional) Sets the amount of time an IP SLAs operation waits for a response from its request packet.
|
Step 24
|
exit
Example:
Router(config-ip-sla-voip)# exit
|
Exits VoIP configuration submode and returns to global configuration mode.
|
Step 25
|
ip sla schedule operation-number [life
{forever | seconds}] [start-time {hh:mm[:ss]
[month day | day month] | pending | now |
after hh:mm:ss] [ageout seconds] [recurring]
Router(config)# ip sla schedule 5 start-time
now life forever
|
Configures the scheduling parameters for an individual IP SLAs operation.
|
Step 26
|
exit
Example:
Router(config)# exit
|
(Optional) Exits global configuration mode and returns to privileged EXEC mode.
|
Step 27
|
show ip sla configuration [operation-number]
Example:
Router# show ip sla configuration 10
|
(Optional) Displays configuration values including all defaults for all IP SLAs operations or a specified operation.
|
Troubleshooting Tips
Use the debug ip sla trace and debug ip sla error commands to help troubleshoot issues with an IP SLAs operation.
What to Do Next
To view and interpret the results of an IP SLAs operation use the show ip sla statistics command. Checking the output for fields that correspond to criteria in your service level agreement will help you determine whether the service metrics are acceptable.
Configuring the Terminating Gateway Using the IP SLAs VoIP Responder Application
Perform this task on the terminating gateway (destination) in order to set up the dial peer and enable the IP SLAs VoIP Responder application to respond to the IP SLAs VoIP test call. The required configuration for setting up the dial peer will vary slightly depending on whether you are using H.323 or SIP.
Prerequisites
In order to use the IP SLAs VoIP call setup functionality, your Cisco IOS software image must support the IP SLAs VoIP test-call application and IP SLAs VoIP Responder application. To determine if your Cisco IOS software image is configured with these applications, use the show call application voice command in EXEC mode.
Note
The IP SLAs VoIP Responder application is different from the IP SLAs Responder (which is configured using the ip sla responder command in global configuration mode).
SUMMARY STEPS
1.
enable
2.
show call application voice [name | summary]
3.
configure terminal
4.
dial-peer voice tag voip
5.
incoming called-number tag
6.
application application-name
7.
session protocol sipv2
8.
exit
DETAILED STEPS
| |
Command or Action
|
Purpose
|
Step 1
|
enable
Example:
Router> enable
|
Enables privileged EXEC mode.
• Enter your password if prompted.
|
Step 2
|
show call application voice [name | summary]
Example:
Router# show call application voice summary
NAME DESCRIPTION
...
ipsla-testcall Basic app to place a simple
call
ipsla-responder Basic app to respond to a
simple call
...
TCL Script Version 2.0 supported.
Call Treatment Action Application - Version 1.
|
(Optional) Displays information about configured voice applications.
• If the summary keyword is entered, the command output displays a one-line summary of each configured voice application.
• If the Cisco IOS IP SLAs VoIP Responder application is configured on the currently loaded Cisco IOS software image, the ipsla-responder name is displayed.
|
Step 3
|
configure terminal
Example:
Router# configure terminal
|
Enters global configuration mode.
|
Step 4
|
dial-peer voice tag voip
Example:
Router(config)# dial-peer voice 6789 voip
|
Defines a particular dial peer, specifies the method of voice encapsulation, and enters dial-peer configuration mode.
• The tag argument consists of one or more digits identifying the dial peer. Range is from 1 to 2147483647.
• The voip keyword indicates a VoIP dial peer using voice encapsulation on an IP network.
|
Step 5
|
incoming called-number tag
Example:
Router(config-dial-peer)# incoming
called-number 6789
|
Specifies a digit string that can be matched by an incoming call to associate the call with a dial peer.
|
Step 6
|
application application-name
Example:
Router(config-dial-peer)# application
ipsla-responder
|
Enables a specific application on a dial peer.
• To enable the Cisco IOS IP SLAs VoIP Responder application, enter ipsla-responder as the application-name argument.
|
Step 7
|
session protocol sipv2
Example:
Router(config-dial-peer)# session protocol
sipv2
|
(Optional) Specifies SIP as the session protocol for the VoIP dial peer.
Note Perform this step only if configuring a SIP call.
|
Step 8
|
exit
Example:
Router(config-dial-peer)# exit
|
Exits dial-peer configuration mode and returns to global configuration mode.
|
Configuration Examples for the IP SLAs VoIP Call Setup Monitoring Operation
This section contains the following configuration examples:
•
Configuring the Originating Gateway: Example
•
Configuring the Terminating Gateway: Example
Configuring the Originating Gateway: Example
The following example shows how to configure an originating gateway to start the IP SLAs VoIP test-call application, set up the dial peer to route the test call, define the VoIP call setup operation, and schedule the VoIP call setup operation. In this example, test-call messages are generated using the Session Initiation Protocol (SIP).
call application session start ipsla-testcall ipsla-testcall
dial-peer voice 6789 voip
session target ipv4:172.29.129.123
voip delay post-dial detect-point alert-ringing destination 6789
ip sla schedule 1 start-time now life forever
Configuring the Terminating Gateway: Example
The following example shows how to configure a terminating gateway to set up the dial peer and enable the IP SLAs VoIP Responder application to respond to the IP SLAs VoIP call setup test call. In this example, test-call messages are generated using the Session Initiation Protocol (SIP).
dial-peer voice 6789 voip
incoming called-number 6789
application ipsla-responder
Where to Go Next
For information about other types of IP SLAs operations and IP SLAs features, see the Cisco IOS IP SLAs Features Roadmap.
Additional References
The following sections provide references related to the IP SLAs VoIP Call Setup Monitoring feature.
Related Documents
Standards
Standard
|
Title
|
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
|
—
|
MIBs
MIB
|
MIBs Link
|
CISCO-RTTMON-MIB
|
To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:
http://www.cisco.com/go/mibs
|
RFCs
RFC
|
Title
|
No new or modified RFCs are supported by this feature, and support for existing RFCs has not been modified by this feature.
|
—
|
Technical Assistance
Description
|
Link
|
The Cisco Technical Support website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.
|
http://www.cisco.com/techsupport
|
Feature Information for the IP SLAs VoIP Call Setup Operation
Table 1 lists the release history for this feature.
Not all commands may be available in your Cisco IOS software release. For release information about a specific command, see the command reference documentation.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Note
Table 1 lists only the Cisco IOS software release that introduced support for a given feature in a given Cisco IOS software release train. Unless noted otherwise, subsequent releases of that Cisco IOS software release train also support that feature.
Table 1 Feature Information for the IP SLAs VoIP Call Setup Operation
Feature Name
|
Releases
|
Feature Information
|
IP SLAs VoIP Call Setup (Post Dial Delay) Monitoring
|
12.3(14)T
|
The Cisco IOS IP SLAs Voice over IP (VoIP) call setup operation allows you to measure network response time for setting up a VoIP call.
|
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