Cisco Nexus 7000 Series NX-OS IP SLAs Configuration Guide, Release 6.x
Configuring IP SLAs UDP Echo Operations
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Configuring IP SLAs UDP Echo Operations

This section describes how to configure an IP Service Level Agreements (SLAs) User Datagram Protocol (UDP) Echo operation to monitor end-to-end response time between a Cisco switch and devices using IPv4. UDP echo accuracy is enhanced by using the IP SLAs Responder at the destination Cisco switch. This module also demonstrates how the results of the UDP echo operation can be displayed and analyzed to determine how a UDP application is performing.

UDP Echo Operation

The UDP echo operation measures end-to-end response time between a Cisco switch and devices using IP. UDP is a transport layer (Layer 4) Internet protocol that is used for many IP services. UDP echo is used to measure response times and test end-to-end connectivity.

In the following figure Switch A is configured as an IP SLAs Responder and Switch B is configured as the source IP SLAs device.





The response time (round-trip time) is computed by measuring the time taken between sending a UDP echo request message from Switch B to the destination switch--Switch A--and receiving a UDP echo reply from Switch A. UDP echo accuracy is enhanced by using the responder at Switch A, the destination Cisco switch. If the destination switch is a Cisco switch, then IP SLAs sends a UDP datagram to any port number that you specified. Using the IP SLAs Responder is optional for a UDP echo operation when using Cisco devices. The IP SLAs Responder cannot be configured on non-Cisco devices.

The results of a UDP echo operation can be useful in troubleshooting issues with business-critical applications by determining the round-trip delay times and testing connectivity to both Cisco and non- Cisco devices.

Guidelines and Limitations for UDP Echo Operations

  • When using IP SLA UDP probes, you might experience RTT spikes of up to 200 ms on the Cisco Nexus 7000 NX-OS Supervisor 1 and spikes of up to 35 ms on the Cisco Nexus 7000 NX-OS Supervisor 2. These are both known issues with the netstack architecture.
  • When IP SLA traffic exceeds 100 kbps, IP SLA operations might timeout. You can enter the no copp profile command to avoid this issue.

Configuring the IP SLAs Responder on the Destination Device

Before You Begin

If you are using the IP SLAs Responder, ensure that the networking device to be used as the responder is a Cisco device and that you have connectivity to that device through the network.

Procedure
     Command or ActionPurpose
    Step 1 enable


    Example: 
    Switch> enable
     

    Enables privileged EXEC mode

    Enter your password if prompted.

     
    Step 2configure terminal


    Example:
    Switch# configure terminal
     

    Enters global configuration mode.

     
    Step 3Do one of the following:
    • ip sla responder

      Example:

       Switch(config)# ip sla responder
    • ip sla responder udp-echo ipaddress ip-address port port

      Example:

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

    -

    • Temporarily enables the IP SLAs Responder functionality on a Cisco device in response to control messages from the source.
    • Required only if the protocol control is disabled on source. This command permanently enables the IP SLAs Responder functionality on a specified IP address and port. Control is enabled by default.
     
    Step 4exit


    Example:
    Switch(config)# exit
     

    Exits global configuration mode and returns to privileged EXEC mode.

     

    Configuring a Basic UDP Echo Operation on the Source Device

    This section describes how to configure a basic UDP echo operation on the source.


    Note

    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.

    Before You Begin

    If you are using the IP SLAs Responder, ensure that you have completed the "Configuring the IP SLAs Responder on the Destination Device" section before you start this task.

    Procedure
       Command or ActionPurpose
      Step 1 enable


      Example: 
      Switch> enable
       

      Enables privileged EXEC mode.

      Enter your password if prompted.

       
      Step 2 configure terminal


      Example: 
      Switch# configure terminal
       

      Enters global configuration mode.

       
      Step 3 ip sla operation-number


      Example: 
      Switch(config)# ip sla 10
       

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

       
      Step 4 udp-echo {destination-ip-address | destination-hostname} destination-port [source-ip {ip-address | hostname} sourceport port-number] [control {enable | disable}]


      Example: 
      Switch(config-ip-sla)# udp-echo 172.29.139.134 5000
       

      Defines a UDP echo operation and enters IP SLA UDP configuration mode.

      Use the control disable keyword combination only if you disable the IP SLAs control protocol on both the source and target switches.

       
      Step 5 frequency seconds


      Example: 
      Switch(config-ip-sla-udp)# frequency 30
       

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

       
      Step 6 end


      Example: 
      Switch(config-ip-sla-udp)# end
       

      Returns to prileged EXEC mode.

       

      Configuring a UDP Echo Operation with Optional Parameters on the Source Device

      This section describes how to configure a UDP echo operation with optional parameters on the source device.


      Note

      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.

      Before You Begin

      If you are using an IP SLAs Responder in this operation, the responder must be configured on the destination device. See the "Configuring the IP SLAs Responder on the Destination Device" section.

      Procedure
         Command or ActionPurpose
        Step 1 enable


        Example: 
        Switch> enable
         

        Enables privileged EXEC mode.

        Enter your password if prompted.

         
        Step 2 configure terminal


        Example: 
        Switch# configure terminal
         

        Enters global configuration mode.

         
        Step 3 ip sla operation-number


        Example: 
        Switch(config)# ip sla 10
         

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

         
        Step 4 udp-echo {destination-ip-address | destination-hostname} destination-port [source-ip {ip-address | hostname} source-port port-number] [control {enable | disable}]


        Example: 
        Switch(config-ip-sla)# udp-echo 172.29.139.134 5000
         

        Defines a UDP echo operation and enters IP SLA UDP configuration mode.

        Use the control disable keyword combination only if you disable the IP SLAs control protocol on both the source and target switches.

         
        Step 5 history buckets-kept size


        Example: 
        Switch(config-ip-sla-udp)# history buckets-kept 25
         

        (Optional) Sets the number of history buckets that are kept during the lifetime of an IP SLAs operation.

         
        Step 6 data-pattern hex-pattern


        Example: 
        Switch(config-ip-sla-udp)# data-pattern
         

        (Optional) Specifies the data pattern in an IP SLAs operation to test for data corruption.

         
        Step 7 history distributions-of-statistics-kept size


        Example: 
        Switch(config-ip-sla-udp)# history distributionsof- statistics-kept 5
         

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

         
        Step 8 history enhanced [interval seconds] [buckets number-of-buckets]


        Example: 
        Switch(config-ip-sla-udp)# history enhanced interval 900 buckets 100
         

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

         
        Step 9 history filter {none | all | overThreshold | failures}


        Example: 
        Switch(config-ip-sla-udp)# history filter failures
                  		(Optional) Defines the type of information kept in the history table for an IP SLAs operation. 
        Step 10 frequency seconds


        Example: 
        Switch(config-ip-sla-udp)# frequency 30
         

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

         
        Step 11 history hours-of-statistics-kept hours


        Example: 
        Switch(config-ip-sla-udp)# history hours-ofstatistics- kept 4
         

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

         
        Step 12 history lives-kept lives


        Example: 
        Switch(config-ip-sla-udp)# history lives-kept 5
         

        (Optional) Sets the number of lives maintained in the history table for an IP SLAs operation.

         
        Step 13 owner owner-id


        Example: 
        Switch(config-ip-sla-udp)# owner admin
         

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

         
        Step 14 request-data-size bytes


        Example: 
        Switch(config-ip-sla-udp)# request-data-size 64
         

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

         
        Step 15 history statistics-distribution-interval milliseconds


        Example: 
        Switch(config-ip-sla-udp)# history statistics distribution- interval 10
         

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

         
        Step 16 tag text


        Example: 
        Switch(config-ip-sla-udp)# tag TelnetPollServer1
         

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

         
        Step 17 threshold milliseconds


        Example: 
        Switch(config-ip-sla-udp)# threshold 10000
         

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

         
        Step 18 timeout milliseconds


        Example: 
        Switch(config-ip-sla-udp)# timeout 10000
         

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

         
        Step 19 tos number


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

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

         
        Step 20 verify-data


        Example: 
        Switch(config-ip-sla-udp)# verify-data
         

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

         
        Step 21 exit


        Example: 
        Switch(config-ip-sla-udp)# exit
         

        Exits UDP configuration submode and returns to global configuration mode.

         

        Scheduling IP SLAs Operations

        This section describes how to schedule IP SLAs operations.

        Before You Begin

        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.
        • List of one or more operation ID numbers to be added to a multioperation group is limited to a maximum of 125 characters, including commas (,).

        Tip
        • 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.
        Procedure
           Command or ActionPurpose
          Step 1 enable


          Example: 
          Switch> enable
           

          Enables privileged EXEC mode.

          Enter your password if prompted.

           
          Step 2 configure terminal


          Example: 
          Switch# configure terminal
           

          Enters global configuration mode.

           
          Step 3Do one of the following:
          • ip sla schedule operation-number [life {forever | seconds}] [starttime {hh : mm[: ss] [month day | day month] | pending | now | after hh : mm : ss}] [ageout seconds] [recurring]

            Example:

             ip sla schedule operation-number [life {forever | seconds}] [starttime {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}] [starttime{ hh:mm[:ss] [month day | day month] | pending | now | after hh:mm:ss}]

            Example:

             Switch(config)# ip sla group schedule 1 3,4,6-9
           

          -

          • For individual IP SLAs operations only: Configures the scheduling parameters for an individual IP SLAs operation.
          • For the multioperations scheduler only: Specifies an IP SLAs operation group number and the range of operation numbers to be scheduled in global configuration mode.
           
          Step 4 exit


          Example: 
          Switch(config)# exit
           

          Exits to privileged EXEC mode.

           
          Step 5 show ip sla group schedule


          Example: 
          Switch# show ip sla group schedule
           

          (Optional) Displays the IP SLAs group schedule details.

           
          Step 6 show ip sla configuration


          Example: 
          Switch# show ip sla configuration
           

          (Optional) Displays the IP SLAs configuration details.

           
          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 Example for a UDP Echo Operation

          This example shows how to configure an IP SLAs operation type of UDP echo that starts immediately and runs indefinitely: 

          ip sla 5
udp-echo 172.29.139.134 5000
frequency 30
request-data-size 160
tos 128
timeout 1000
tag FLL-RO
ip sla schedule 5 life forever start-time now

          Feature History for UDP Echo

          This table includes only the updates for those releases that have resulted in additions or changes to the feature.

          Table 1 Feature History for UDP Echo
          Feature Name Release Feature Information

          UDP Echo

          6.1(1)

          This feature was introduced.