IP SLAs Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches)
Configuring IP SLAs UDP Jitter Operations
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Configuring IP SLAs UDP Jitter Operations

Configuring IP SLAs UDP Jitter Operations

This document describes how to configure an IP 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 Cisco software commands.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and 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 module.

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 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 and receiving sequence information, and sending and receiving time stamps from the source and the operational target. Based on this information, 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 sending and receiving data may be different (asymmetric), the per-direction data allows 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, T milliseconds apart, from a source device to a target device, 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 is 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 a 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:
    Device> enable
     

    Enables privileged EXEC mode.

    • Enter your password if prompted.
     
    Step 2 configure terminal


    Example:
    Device# 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:
    Device(config)# ip sla responder


    Example:
    Device(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 the source.

    (Optional) Required only if protocol control is disabled on the source. Enables IP SLAs responder functionality on the specified IP address and port.
    • Protocol control is enabled by default.
     
    Step 4 exit


    Example:
    Device(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 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.    end

      7.    show ip sla configuration [operation-number]


    DETAILED STEPS
        Command or Action Purpose
      Step 1 enable


      Example:
      Device> enable
       

      Enables privileged EXEC mode.

      • Enter your password if prompted.
       
      Step 2 configure terminal


      Example:
      Device# configure terminal
       

      Enters global configuration mode.

       
      Step 3 ip sla operation-number


      Example:
      Device(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:
      Device(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 destination devices.
       
      Step 5 frequency seconds


      Example:
      Device(config-ip-sla-jitter)# frequency 30
       

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

       
      Step 6 end


      Example:
      Device(config-ip-sla-jitter)# end
       

      Returns to privileged EXEC mode.

       
      Step 7 show ip sla configuration [operation-number]


      Example:
      Device# show ip sla configuration 10
       

      (Optional) Displays configuration values including all defaults for all IP SLAs operations or a specified operation.

       

      Configuring 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.    end

        20.    show ip sla configuration [operation-number]


      DETAILED STEPS
          Command or Action Purpose
        Step 1 enable


        Example:
        Device> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.
         
        Step 2 configure terminal


        Example:
        Device# configure terminal
         

        Enters global configuration mode.

         
        Step 3 ip sla operation-number


        Example:
        Device(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:
        Device(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 devices.
         
        Step 5 history distributions-of-statistics-kept size


        Example:
        Device(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:
        Device(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:
        Device(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:
        Device(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:
        Device(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:
        Device(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:
        Device(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:
        Device(config-ip-sla-jitter)# tag TelnetPollServer1 
         

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

         
        Step 13 threshold milliseconds


        Example:
        Device(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:
        Device(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:
        Device(config-ip-sla-jitter)# tos 160 


        Example:
        Device(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:
        Device(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:
        Device(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:
        Device(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 end


        Example:
        Device(config-ip-sla-jitter)# end
         

        Returns to privileged EXEC mode.

         
        Step 20 show ip sla configuration [operation-number]


        Example:
        Device# show ip sla configuration 10
         

        (Optional) Displays configuration values including all defaults for all IP SLAs operations or a specified operation.

         

        Scheduling IP SLAs Operations


        Note


        • All IP SLAs operations to be scheduled must be already configured.
        • The frequency of all operations scheduled in a multioperation group must be the same.
        • The list of one or more operation ID numbers to be added to a multioperation group is limited to a maximum of 125 characters in length, including commas (,).

        SUMMARY STEPS

          1.    enable

          2.    configure terminal

          3.    Do one of the following:

          • 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]
          • ip sla group schedule group-operation-number operation-id-numbers schedule-period schedule-period-range [ageout seconds] [frequency group-operation-frequency] [life {forever | seconds}] [start-time{hh:mm[:ss] [month day | day month] | pending | now | after hh:mm[:ss]}]

          4.    exit

          5.    show ip sla group schedule

          6.    show ip sla configuration


        DETAILED STEPS
            Command or Action Purpose
          Step 1 enable


          Example:
          Device> enable
           

          Enables privileged EXEC mode.

          • Enter your password if prompted.
           
          Step 2 configure terminal


          Example:
          Device# configure terminal
           

          Enters global configuration mode.

           
          Step 3 Do one of the following:
          • 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]
          • ip sla group schedule group-operation-number operation-id-numbers schedule-period schedule-period-range [ageout seconds] [frequency group-operation-frequency] [life {forever | seconds}] [start-time{hh:mm[:ss] [month day | day month] | pending | now | after hh:mm[:ss]}]


          Example:
          Device(config)# ip sla schedule 10 life forever start-time now


          Example:
          Device(config)# ip sla group schedule 1 3,4,6-9 life forever start-time now 
           
          • Configures the scheduling parameters for an individual IP SLAs operation.
          • Specifies an IP SLAs operation group number and the range of operation numbers for a multioperation scheduler.
           
          Step 4 exit


          Example:
          Device(config)# exit
           

          Exits to privileged EXEC mode.

           
          Step 5 show ip sla group schedule


          Example:
          Device# show ip sla group schedule
           

          (Optional) Displays IP SLAs group schedule details.

           
          Step 6 show ip sla configuration


          Example:
          Device# show ip sla configuration
           

          (Optional) Displays IP SLAs configuration details.

           

          Troubleshooting Tips

          • If the IP SLAs operation is not running and not 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 data verification is 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 debug ip sla 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.

          operation)

          To display and interpret the results of an IP SLAs operation, use the show ip sla statistics command. Check the output for fields that correspond to criteria in your service level agreement to 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 Command List, All Releases

          Cisco IOS IP SLAs commands

          Cisco IOS IP SLAs Command Reference

          MIBs

          MIBs

          MIBs Link

          • CISCO-RTTMON-MIB
          • IPV6-FLOW-LABEL-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

          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 the IP SLAs UDP Jitter Operation

          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

          Cisco IOS XE Release 2.1

          15.0(1)S

          Cisco IOS XE 3.1.0SG

          Cisco IOS XE Release 3.2SE

          The 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.

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

          12.2(33)SRC

          12.2(33)SB

          12.4(20)T

          Cisco IOS XE Release 2.1

          Cisco IOS XE 3.1.0SG

          12.2(50)SY

          Cisco IOS XE Release 3.2SE

          Support was added for operability in IPv6 networks.