Configuring IP SLAs HTTP Operations

This module describes how to configure an IP Service Level Agreements (SLAs) HTTP operation to monitor the response time between a Cisco device and an HTTP server to retrieve a web page. The IP SLAs HTTP operation supports both the normal GET requests and customer RAW requests. This module also demonstrates how the results of the HTTP operation can be displayed and analyzed to determine how an HTTP server is performing.

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.

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.

Restrictions for IP SLAs HTTP Operations

  • IP SLAs HTTP operations support only HTTP/1.0.

  • HTTP/1.1 is not supported for any IP SLAs HTTP operation, including HTTP RAW requests.

Information About IP SLAs HTTP Operations

HTTP Operation

The HTTP operation measures the round-trip time (RTT) between a Cisco device and an HTTP server to retrieve a web page. The HTTP server response time measurements consist of three types:

  • DNS lookup­RTT taken to perform domain name lookup.

  • TCP Connect--RTT taken to perform a TCP connection to the HTTP server.

  • HTTP transaction time--RTT taken to send a request and get a response from the HTTP server. The operation retrieves only the home HTML page.

The DNS operation is performed first and the DNS RTT is measured. Once the domain name is found, a TCP Connect operation to the appropriate HTTP server is performed and the RTT for this operation is measured. The final operation is an HTTP request and the RTT to retrieve the home HTML page from the HTTP server is measured. One other measurement is made and called the time to first byte which measures the time from the start of the TCP Connect operation to the first HTML byte retrieved by the HTTP operation. The total HTTP RTT is a sum of the DNS RTT, the TCP Connect RTT, and the HTTP RTT.

For GET requests, IP SLAs will format the request based on the specified URL. For RAW requests, IP SLAs requires the entire content of the HTTP request. When a RAW request is configured, the raw commands are specified in HTTP RAW configuration mode. A RAW request is flexible and allows you to control fields such as authentication. An HTTP request can be made through a proxy server.

The results of an HTTP operation can be useful in monitoring your web server performance levels by determining the RTT taken to retrieve a web page.

Regardless of the HTTP errors, the IP SLA works fine. Currently, the error codes are determined, and the IP SLA HTTP operation goes down only if the return code is not 200.


Note

The only time the SLA probe goes down is when the SLA is unable to establish a TCP connection or is unable to receive an answer from the Remote server to its HTTP request.

How to Configure IP SLAs HTTP Operations

Configuring an HTTP GET Operation on the Source Device


Note

This operation does not require an IP SLAs Responder on the destination device.

Perform only one of the following tasks:

Configuring a Basic HTTP GET Operation on the Source Device

SUMMARY STEPS

    1.    enable

    2.    configure terminal

    3.    ip sla operation-number

    4.    http {get | raw} url [name-server ip-address] [version version-number] [source-ip {ip-address | hostname}] [source-port port-number] [cache {enable | disable}] [proxy proxy-url]

    5.    frequency seconds

    6.    end


DETAILED STEPS
     Command or ActionPurpose
    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 http {get | raw} url [name-server ip-address] [version version-number] [source-ip {ip-address | hostname}] [source-port port-number] [cache {enable | disable}] [proxy proxy-url]


    Example:
    Device(config-ip-sla)# http get http://198.133.219.25
     

    Defines an HTTP operation and enters IP SLA configuration mode.

     
    Step 5 frequency seconds


    Example:
    Device(config-ip-sla-http)# frequency 90
     

    (Optional) Sets the rate at which a specified IP SLAs HTTP operation repeats. The default and minimum frequency value for an IP SLAs HTTP operation is 60 seconds.

     
    Step 6 end


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

    Exits to privileged EXEC mode.

     

    Configuring an HTTP GET Operation with Optional Parameters on the Source Device

    SUMMARY STEPS

      1.    enable

      2.    configure terminal

      3.    ip sla operation-number

      4.    http {get | raw} url [name-server ip-address] [version version-number] [source-ip {ip-address | hostname}] [source-port port-number] [cache {enable | disable}] [proxy proxy-url]

      5.    history distributions-of-statistics-kept size

      6.    frequency seconds

      7.    history hours-of-statistics-kept hours

      8.    http-raw-request

      9.    owner owner-id

      10.    history statistics-distribution-interval milliseconds

      11.    tag text

      12.    threshold milliseconds

      13.    timeout milliseconds

      14.    tos number

      15.    end


    DETAILED STEPS
       Command or ActionPurpose
      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 http {get | raw} url [name-server ip-address] [version version-number] [source-ip {ip-address | hostname}] [source-port port-number] [cache {enable | disable}] [proxy proxy-url]


      Example: 
      Device(config-ip-sla)# http get http://198.133.219.25
       

      Defines an HTTP operation and enters IP SLA configuration mode.

       
      Step 5 history distributions-of-statistics-kept size


      Example: 
      Device(config-ip-sla-http)# history distributions-of-statistics-kept 5
       

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

       
      Step 6 frequency seconds


      Example: 
      Device(config-ip-sla-http)# frequency 90
       

      (Optional) Sets the rate at which a specified IP SLAs HTTP operation repeats. The default and minimum frequency value for an IP SLAs HTTP operation is 60 seconds.

       
      Step 7 history hours-of-statistics-kept hours


      Example: 
      Device(config-ip-sla-http)# history hours-of-statistics-kept 4
       

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

       
      Step 8 http-raw-request


      Example: 
      Device(config-ip-sla-http)# http-raw-request
       

      (Optional) Explicitly specifies the options for a GET request for an IP SLAs HTTP operation.

       
      Step 9 owner owner-id


      Example: 
      Device(config-ip-sla-http)# owner admin
       

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

       
      Step 10 history statistics-distribution-interval milliseconds


      Example: 
      Device(config-ip-sla-http)# history statistics-distribution-interval 10
       

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

       
      Step 11 tag text


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

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

       
      Step 12 threshold milliseconds


      Example: 
      Device(config-ip-sla-http)# threshold 10000
       

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

       
      Step 13 timeout milliseconds


      Example: 
      Device(config-ip-sla-http)# timeout 10000
       

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

       
      Step 14 tos number


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

      (Optional) Defines a type of service (ToS) byte in the IP header of an IP SLAs operation.

       
      Step 15 end


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

      Exits to privileged EXEC mode.

       

      Configuring an HTTP RAW Operation on the Source Device


      Note

      This operation does not require an IP SLAs Responder on the destination device.

      SUMMARY STEPS

        1.    enable

        2.    configure terminal

        3.    ip sla operation-number

        4.    http {get | raw} url [name-server ip-address] [version version-number] [source-ip {ip-address | hostname}] [source-port port-number] [cache {enable | disable}] [proxy proxy-url]

        5.    http-raw-request

        6.    Enter the required HTTP 1.0 command syntax.

        7.    end


      DETAILED STEPS
         Command or ActionPurpose
        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 http {get | raw} url [name-server ip-address] [version version-number] [source-ip {ip-address | hostname}] [source-port port-number] [cache {enable | disable}] [proxy proxy-url]


        Example:
        Device(config-ip-sla)# http raw http://198.133.219.25
         

        Defines an HTTP operation.

         
        Step 5 http-raw-request


        Example:
        Device(config-ip-sla)# http-raw-request
         

        Enters HTTP RAW configuration mode.

         
        Step 6 Enter the required HTTP 1.0 command syntax.

        Example:
        Device(config-ip-sla-http)# GET /en/US/hmpgs/index.html HTTP/1.0\r\n\r\n
         

        Specifies all the required HTTP 1.0 commands.

         
        Step 7 end


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

        Exits to privileged EXEC mode.

         

        Scheduling IP SLAs Operations

        Before You Begin

        • All IP Service Level Agreements (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 must be limited to a maximum of 125 characters in length, including commas (,).

        SUMMARY STEPS

          1.    enable

          2.    configure terminal

          3.    Enter one of the following commands:

          • 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 | schedule-together} [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.    end

          5.    show ip sla group schedule

          6.    show ip sla configuration


        DETAILED STEPS
           Command or ActionPurpose
          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 Enter one of the following commands:
          • 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 | schedule-together} [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
          Device(config)# ip sla group schedule 10 schedule-period frequency
          Device(config)# ip sla group schedule 1 3,4,6-9 life forever start-time now 
          Device(config)# ip sla schedule 1 3,4,6-9 schedule-period 50 frequency range 80-100
           

          • 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 end


          Example: 
          Device(config)# end
           

          Exits global configuration mode and returns 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 Service Level Agreements (SLAs) operation is not running and not generating statistics, add the verify-data command to the configuration (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 Service Level Agreements (SLAs) operation, see the “Configuring Proactive Threshold Monitoring” section.

          Configuration Examples for IP SLAs HTTP Operations

          Example Configuring an HTTP GET Operation

          The following example show how to create and configure operation number 8 as an HTTP GET operation. The destination URL IP address represents the www.cisco.com website. The following figure depicts the HTTP GET operation.

          Figure 1. HTTP Operation

          Device B Configuration

          ip sla 8
 http get url http://198.133.219.25
!
ip sla schedule 8 start-time now

          Example Configuring an HTTP RAW Operation

          The following example shows how to configure an HTTP RAW operation. To use the RAW commands, enter HTTP RAW configuration mode by using the http-raw-request command in IP SLA configuration mode. The IP SLA HTTP RAW configuration mode is indicated by the (config-ip-sla-http) router prompt. 

          ip sla 8
 http raw url http://198.133.219.25
 http-raw-request
 GET /en/US/hmpgs/index.html HTTP/1.0\r\n
 \r\n
 end
ip sla schedule 8 life forever start-time now

          Example Configuring an HTTP RAW Operation Through a Proxy Server

          The following example shows how to configure an HTTP RAW operation through a proxy server. The proxy server is www.proxy.cisco.com and the HTTP server is www.yahoo.com. 

          ip sla 8
 http raw url http://www.proxy.cisco.com
 http-raw-request
 GET http://www.yahoo.com HTTP/1.0\r\n
 \r\n
 end
ip sla schedule 8 life forever start-time now

          Example Configuring an HTTP RAW Operation with Authentication

          The following example shows how to configure an HTTP RAW operation with authentication. 

          ip sla 8
 http raw url http://site-test.cisco.com
 http-raw-request
 GET /lab/index.html HTTP/1.0\r\n
 Authorization: Basic btNpdGT4biNvoZe=\r\n
 \r\n
 end
ip sla schedule 8 life forever start-time now

          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 and RFCs

          Standard/RFC

          Title

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

          --

          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

          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 HTTP 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 1 Feature Information for IP SLAs HTTP Operations

          Feature Name

          Releases

          Feature Information

          IP SLAs HTTP Operation

          Cisco IOS XE Release 2.1

          The Cisco IOS IP SLAs Hypertext Transfer Protocol (HTTP) operation allows you to measure the network response time between a Cisco device and an HTTP server to retrieve a web page.

          IPSLA 4.0 - IP v6 phase2

          Cisco IOS XE Release 3.7S

          Support was added for operability in IPv6 networks. The following commands are introduced or modified: http (IP SLA), show ip sla configuration, show ip sla summary.

          IP SLAs VRF Aware 2.0

          Cisco IOS XE Release 3.8S

          Support was added for IP SLAs VRF-aware capabilities for TCP connect, FTP, HTTP and DNS client operation types.