Configuring IP SLAs UDP Jitter Operations

Last Updated: July 18, 2011

This document describes how to configure anIP Service Level Agreements (SLAs) UDP jitter operation to analyze round-trip delay, one-way delay, one-way jitter, one-way packet loss, and connectivity in networks that carry UDP traffic in IPv4 or IPv6 networks. This module also demonstrates how the data gathered using the UDP jitter operation can be displayed and analyzed using the Cisco software commands.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the Feature Information Table at the end of this document.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Prerequisites

  • Time synchronization, such as that provided by NTP, is required between the source and the target device in order to provide accurate one-way delay (latency) measurements. To configure NTP on the source and target devices, perform the tasks in the “Performing Basic System Management” chapter of the Cisco IOS XE Network Management Configuration Guide. Time synchronization is not required for the one-way jitter and packet loss measurements, however. If the time is not synchronized between the source and target devices, one-way jitter and packet loss data will be returned, but values of “0” will be returned for the one-way delay measurements provided by the UDP jitter operation.
  • Before configuring any IP SLAs application, you can use the show ip sla application command to verify that the operation type is supported on your software image.

Information About IP SLAs UDP Jitter Operations

IP SLAs UDP Jitter Operation

The IP SLAs UDP jitter operation was primarily designed to diagnose network suitability for real-time traffic applications such as voice over IP (VoIP), video over IP, or real-time conferencing.

Jitter means inter-packet delay variance. When multiple packets are sent consecutively from source to destination, for example, 10 ms apart, and if the network is behaving ideally, the destination should be receiving them 10 ms apart. But if there are delays in the network (like queuing, arriving through alternate routes, and so on) the arrival delay between packets might be greater than or less than 10 ms. Using this example, a positive jitter value indicates that the packets arrived greater than 10 ms apart. If the packets arrive 12 ms apart, then positive jitter is 2 ms; if the packets arrive 8 ms apart, then negative jitter is 2 ms. For delay-sensitive networks like VoIP, positive jitter values are undesirable, and a jitter value of 0 is ideal.

However, the IP SLAs UDP jitter operation does more than just monitor jitter. As the UDP jitter operation includes the data returned by the IP SLAs UDP operation, the UDP jitter operation can be used as a multipurpose data gathering operation. The packets IP SLAs generates carry packet sending sequence and receiving sequence information, and sending and receiving time stamps from the source and the operational target. Based on these, UDP jitter operations are capable of measuring the following:

  • Per-direction jitter (source to destination and destination to source)
  • Per-direction packet-loss
  • Per-direction delay (one-way delay)
  • Round-trip delay (average round-trip time)

As the paths for the sending and receiving of data may be different (asymmetric), the per-direction data allow you to more readily identify where congestion or other problems are occurring in the network.

The UDP jitter operation functions by generating synthetic (simulated) UDP traffic. The UDP jitter operation sends N UDP packets, each of size S, sent T milliseconds apart, from a source router to a target router, at a given frequency of F. By default, ten packet-frames (N), each with a payload size of 10 bytes (S)are generated every 10 ms (T), and the operation is repeated every 60 seconds (F). Each of these parameters are user-configurable, so as to best simulate the IP service you are providing, or want to provide, as shown in the table below.

Table 1 UDP Jitter Operation Parameters

UDP Jitter Operation Parameter

Default

Configured Using:

Number of packets (N)

10 packets

udp-jitter command, num-packets option

Payload size per packet (S)

32 bytes

request-data-size command

Time between packets, in milliseconds (T)

20 ms

udp-jitter command, interval option

Elapsed time before the operation repeats, in seconds (F)

60 seconds

frequency (IP SLA) command

The IP SLAs operations function by generating synthetic (simulated) network traffic. A single IP SLAs operation (for example, IP SLAs operation 10) will repeat at a given frequency for the lifetime of the operation.

How to Configure IP SLAs UDP Jitter Operations

Configuring the IP SLAs Responder on the Destination Device


Note

A responder should not configure a permanent port for the same sender. If the responder configures the permanent port for the same sender, even if the packets are successfully sent (no timeout or packet loss issues), the jitter values will be zero.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.   Do one of the following:

  • ip sla responder
  • ip sla responder udp-echo ipaddress ip-address port port

4.    exit


DETAILED STEPS
  Command or Action Purpose
Step 1
enable


Example:

Router> enable

 

Enables privileged EXEC mode.

  • Enter your password if prompted.
 
Step 2
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 3
Do one of the following:
  • ip sla responder
  • ip sla responder udp-echo ipaddress ip-address port port


Example:

Router(config)# ip sla responder



Example:

Router(config)# ip sla responder udp-echo ipaddress 172.29.139.132 port 5000

 

(Optional) Temporarily enables IP SLAs Responder functionality on a Cisco device in response to control messages from source.

or

(Optional) Required only if protocol control is disabled on source. Permanently enables IP SLAs Responder functionality on specified IP address and port.

  • Control is enabled by default.
 
Step 4
exit


Example:

Router(config)# exit

 

(Optional) Exits global configuration mode and returns to privileged EXEC mode.

 

Configuring and Scheduling a UDP Jitter Operation on the Source Device

Perform only one of the following tasks:

Configuring and Scheduling a Basic UDP Jitter Operation on the Source Device

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip sla operation-number

4.    udp-jitter {destination-ip-address | destination-hostname} destination-port [source-ip {ip-address | hostname}] [source-port port-number] [control {enable | disable}] [num-packets number-of-packets] [interval interpacket-interval]

5.    frequency seconds

6.    exit

7.    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]

8.    exit

9.    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
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 3
ip sla operation-number


Example:

Router(config)# ip sla 10

 

Begins configuration for an IP SLAs operation and enters IP SLA configuration mode.

 
Step 4
udp-jitter {destination-ip-address | destination-hostname} destination-port [source-ip {ip-address | hostname}] [source-port port-number] [control {enable | disable}] [num-packets number-of-packets] [interval interpacket-interval]


Example:

Router(config-ip-sla)# udp-jitter 172.29.139.134 5000

 

Configures the IP SLAs operation as a UDP jitter operation and enters UDP jitter configuration submode.

  • Use the control disable keyword combination only if you disable the IP SLAs control protocol on both the source and target routers.
 
Step 5
frequency seconds


Example:

Router(config-ip-sla-jitter)# frequency 30

 

(Optional) Sets the rate at which a specified IP SLAs operation repeats.

 
Step 6
exit


Example:

Router(config-ip-sla-jitter)# exit

 

Exits UDP jitter configuration submode and returns to global configuration mode.

 
Step 7
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]


Example:

Router(config)# ip sla schedule 5 start-time now life forever

 

Configures the scheduling parameters for an individual IP SLAs operation.

 
Step 8
exit


Example:

Router(config)# exit

 

(Optional) Exits global configuration mode and returns to privileged EXEC mode.

 
Step 9
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
  • If the IP SLAs operation is not running and generating statistics, add the verify-data command to the configuration of the operation (while configuring in IP SLA configuration mode) to enable data verification. When enabled, each operation response is checked for corruption. Use the verify-data command with caution during normal operations because it generates unnecessary overhead.
  • Use the debugipsla trace and debug ip sla error commands to help troubleshoot issues with an IP SLAs operation.
What to Do Next

To add proactive threshold conditions and reactive triggering for generating traps, or for starting another operation, to an IP SLAs operation, see the "Configuring Proactive Threshold Monitoring" section.

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 and Scheduling a UDP Jitter Operation with Additional Characteristics


Note
  • The IP SLAs UDP jitter operation does not support the IP SLAs History feature (statistics history buckets) because of the large data volume involved with UDP jitter operations. This means that the following commands are not supported for UDP jitter operations: history buckets-kept, history filter, history lives-kept, samples-of-history-kept, and show ip sla history.
  • The MIB used by IP SLAs (CISCO-RTTMON-MIB) limits the hours-of-statistics kept for the UDP jitter operation to two hours. Configuring a larger value using the history hours-of-statisticshours global configuration change will not increase the value beyond two hours. However, the Data Collection MIB can be used to collect historical data for the operation. For information, see the CISCO-DATA-COLLECTION-MIB at http://www.cisco.com/go/mibs ).
Before You Begin

Before configuring a UDP jitter operation on the source device, the IP SLAs Responder must be enabled on the target device (the operational target). The IP SLAs Responder is available only on Cisco IOS software-based devices. To enable the Responder, perform the task in the “Configuring the IP SLAs Responder on the Destination Device” section.


SUMMARY STEPS

1.    enable

2.    configure terminal

3.    ip sla operation-number

4.    udp-jitter {destination-ip-address | destination-hostname} destination-port [source-ip {ip-address | hostname}] [source-port port-number] [control {enable | disable}] [num-packets number-of-packets] [interval interpacket-interval]

5.    history distributions-of-statistics-kept size

6.    history enhanced [interval seconds] [buckets number-of-buckets]

7.    frequency seconds

8.    history hours-of-statistics-kept hours

9.    owner owner-id

10.    request-data-size bytes

11.    history statistics-distribution-interval milliseconds

12.    tag text

13.    threshold milliseconds

14.    timeout milliseconds

15.   Do one of the following:

  • tos number
  • traffic-class number

16.    flow-label number

17.    verify-data

18.    vrf vrf-name

19.    exit

20.    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]

21.    exit

22.    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
configure terminal


Example:

Router# configure terminal

 

Enters global configuration mode.

 
Step 3
ip sla operation-number


Example:

Router(config)# ip sla 10

 

Begins configuration for an IP SLAs operation and enters IP SLA configuration mode.

 
Step 4
udp-jitter {destination-ip-address | destination-hostname} destination-port [source-ip {ip-address | hostname}] [source-port port-number] [control {enable | disable}] [num-packets number-of-packets] [interval interpacket-interval]


Example:

Router(config-ip-sla)# udp-jitter 172.29.139.134 5000

 

Configures the IP SLAs operation as a UDP jitter operation and enters UDP jitter configuration submode.

  • Use the control disable keyword combination only if you disable the IP SLAs control protocol on both the source and target routers.
 
Step 5
history distributions-of-statistics-kept size


Example:

Router(config-ip-sla-jitter)# history distributions-of-statistics-kept 5

 

(Optional) Sets the number of statistics distributions kept per hop during an IP SLAs operation.

 
Step 6
history enhanced [interval seconds] [buckets number-of-buckets]


Example:

Router(config-ip-sla-jitter)# history enhanced interval 900 buckets 100

 

(Optional) Enables enhanced history gathering for an IP SLAs operation.

 
Step 7
frequency seconds


Example:

Router(config-ip-sla-jitter)# frequency 30

 

(Optional) Sets the rate at which a specified IP SLAs operation repeats.

 
Step 8
history hours-of-statistics-kept hours


Example:

Router(config-ip-sla-jitter)# history hours-of-statistics-kept 4

 

(Optional) Sets the number of hours for which statistics are maintained for an IP SLAs operation.

 
Step 9
owner owner-id


Example:

Router(config-ip-sla-jitter)# owner admin

 

(Optional) Configures the Simple Network Management Protocol (SNMP) owner of an IP SLAs operation.

 
Step 10
request-data-size bytes


Example:

Router(config-ip-sla-jitter)# request-data-size 64

 

(Optional) Sets the protocol data size in the payload of an IP SLAs operation's request packet.

 
Step 11
history statistics-distribution-interval milliseconds


Example:

Router(config-ip-sla-jitter)# history statistics-distribution-interval 10

 

(Optional) Sets the time interval for each statistics distribution kept for an IP SLAs operation.

 
Step 12
tag text


Example:

Router(config-ip-sla-jitter)# tag TelnetPollServer1

 

(Optional) Creates a user-specified identifier for an IP SLAs operation.

 
Step 13
threshold milliseconds


Example:

Router(config-ip-sla-jitter)# threshold 10000

 

(Optional) Sets the upper threshold value for calculating network monitoring statistics created by an IP SLAs operation.

 
Step 14
timeout milliseconds


Example:

Router(config-ip-sla-jitter)# timeout 10000

 

(Optional) Sets the amount of time an IP SLAs operation waits for a response from its request packet.

 
Step 15
Do one of the following:
  • tos number
  • traffic-class number


Example:

Router(config-ip-sla-jitter)# tos 160



Example:

Router(config-ip-sla-jitter)# traffic-class 160

 

(Optional) In an IPv4 network only, defines the ToS byte in the IPv4 header of an IP SLAs operation.

or

(Optional) In an IPv6 network only, defines the traffic class byte in the IPv6 header for a supported IP SLAs operation.

 
Step 16
flow-label number


Example:

Router(config-ip-sla-jitter)# flow-label 112233

 

(Optional) In an IPv6 network only, defines the flow label field in the IPv6 header for a supported IP SLAs operation.

 
Step 17
verify-data


Example:

Router(config-ip-sla-jitter)# verify-data

 

(Optional) Causes an IP SLAs operation to check each reply packet for data corruption.

 
Step 18
vrf vrf-name


Example:

Router(config-ip-sla-jitter)# vrf vpn-A

 

(Optional) Allows monitoring within Multiprotocol Label Switching (MPLS) Virtual Private Networks (VPNs) using IP SLAs operations.

 
Step 19
exit


Example:

Router(config-ip-sla-jitter)# exit

 

Exits UDP jitter configuration submode and returns to global configuration mode.

 
Step 20
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]


Example:

Router(config)# ip sla schedule 5 start-time now life forever

 

Configures the scheduling parameters for an individual IP SLAs operation.

 
Step 21
exit


Example:

Router(config)# exit

 

(Optional) Exits global configuration mode and returns to privileged EXEC mode.

 
Step 22
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
  • If the IP SLAs operation is not running and generating statistics, add the verify-data command to the configuration of the operation (while configuring in IP SLA configuration mode) to enable data verification. When enabled, each operation response is checked for corruption. Use the verify-data command with caution during normal operations because it generates unnecessary overhead.
  • Use the debugipsla trace and debug ip sla error commands to help troubleshoot issues with an IP SLAs operation.
What to Do Next

To add proactive threshold conditions and reactive triggering for generating traps, or for starting another operation, to an IP SLAs operation, see the "Configuring Proactive Threshold Monitoring" section.

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.

Configuration Examples for IP SLAs UDP Jitter Operations

Example Configuring a UDP Jitter Operation

In the following example, two operations are configured as UDP jitter operations, with operation 2 starting five seconds after the first operation. Both operations will run indefinitely.

ip sla 1
 udp-jitter 20.0.10.3 65051 num-packets 20
 request-data-size 160
 tos 128
 frequency 30
ip sla schedule 1 start-time after 00:05:00
ip sla 2
 udp-jitter 20.0.10.3 65052 num-packets 20 interval 10
 request-data-size 20
 tos 64
 frequency 30
ip sla schedule 2 start-time after 00:05:05

On the target (destination) device:

ip sla responder

Additional References

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Commands List, All Releases

Cisco IOS IP SLAs commands

Cisco IOS IP SLAs Command Reference

Standards

Standards

Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by features in this document.

--

MIBs

MIBs

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

RFCs

Title

No specific RFCs are supported by the features in this document.

--

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for IP SLAs UDP Jitter Operations

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Table 2 Feature Information for IP SLAs UDP Jitter Operations

Feature Name

Releases

Feature Information

IP SLAs UDP Jitter Operation

12.2(31)SB2

12.2(33)SRB1

12.2(33)SXH

12.3(14)T

15.0(1)S

Cisco IOS XE 3.1.0SG

The Cisco IOS IP SLAs User Datagram Protocol (UDP) jitter operation allows you to measure round-trip delay, one-way delay, one-way jitter, one-way packet loss, and connectivity in networks that carry UDP traffic.

IPv6 - IP SLAs (UDP Jitter, UDP Echo, ICMP Echo, TCP Connect)

12.2(33)SRC

12.2(33)SB

12.4(20)T

Cisco IOS XE 3.1.0SG

12.2(50)SY

Support was added for operability in IPv6 networks.

Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)

Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.