Configuring thresholds for network performance calculations

Effectiveness of data transfer is determined by Key Performance Indicators (KPIs) and thresholds. You can set the thresholds used for network performance calculations in the Advanced Properties Editor.

This screen is available only to users with administrator rights.

  1. Open the Administration console.
    • On the NAM Server main menu bar, select Tools ► Admin console, or
    • In your browser address line, enter:
      http://server_IP_address/DiagConsole
      where server_IP_address is the NAM Server IP address.
  2. In the Configuration Management section, click Advanced properties editor.
  3. Use the right arrow right arrow to page through the settings until you reach the Advanced Properties Editor - Performance Thresholds page.

Normal comparison mode

This is the default mode used for network performance calculations. To configure its properties, in the Performance Thresholds section, make sure that the Site Performance Objective (Thresholds.PERF_OBJ_LOC) property value is set to Normals.

  1. Comparison mode The comparison mode is set to Normals. This mode enables advanced network performance calculations.

  2. 'Safety' margin (M) for thresholds (T) based on historical averages (N)

    (RTM_UT_PERCENT_VALUE)

    This is a predefined factor by which the defined thresholds are multiplied. By default, it is equal to 100%, which means that your KPI value must be 100% larger than the normal value before indicating network-related problems.

  3. Performance metrics
    These are the KPIs used for network performance calculations. Note that Client realized bandwidth and Server realized bandwidth are not available in Normals mode.

    • Use Client ACK RTT as performance metric
      (LOC_USE_CLI_ACK_RTT_THR)
    • Use End-to-end RTT as performance metric
      (LOC_USE_RTT_THR)
    • Use loss rate as performance metric
      (LOC_USE_LR_THR)
  4. Maximum values of performance metrics

    • Max value of Client ACK RTT when it is always treated as good
      (LOC_MIN_CLI_ACK_RTT_THR)
    • Max value of End-to-end RTT when it is always treated as good
      (LOC_MIN_RTT_THR)
    • Max value of loss rate when it always treated as good
      (LOC_MIN_LR_THR)

    These are the cut-off thresholds. A loss rate less than 1% and an RTT less than 100 ms is always good.

Fixed threshold mode

This mode is used for simpler calculations. To configure its properties, in the Performance Thresholds section, make sure that the Site Performance Objective (Thresholds.PERF_OBJ_LOC) property value is set to Constants.

  1. Comparison mode
    The comparison mode is set to Constants. This mode enables simple network performance calculations.
  2. Performance metrics
    These are the KPIs used for network performance calculations. Note that Client ACK RTT is not available in Constants mode.
    • Use Client ACK RTT as performance metric
      (LOC_USE_CLI_ACK_RTT_THR)
    • Use client realized bandwidth as performance metric
      (LOC_USE_TPUT_CLI_THR)
    • Use End-to-end RTT as performance metric
      (LOC_USE_RTT_THR)
    • Use loss rate as performance metric
      (LOC_USE_LR_THR)
    • Use server realized bandwidth as performance metric
      (LOC_USE_TPUT_THR)
  3. Fixed thresholds for performance metrics
    • Client ACK RTT threshold
      (ACKRTT_THRSH)
    • Client/Upstream loss rate threshold
      (CLI_LOSS_RATE_THRSH)
    • Client/Upstream Realized Bandwidth threshold
      (THRPUT_THRSH_CLI)
    • End-to-end RTT threshold RTT_THRSH
      (RTT_THRSH)
    • Server/Downstream loss rate threshold
      (LOSS_RATE_THRSH)
    • Server/Downstream Realized Bandwidth threshold
      (THRPUT_THRSH)

Modifying the network performance criteria (NAM Server only)

By default, the metrics used for determining the network performance in NAM Server reports are: average end-to-end RTT, average upstream loss rate, and average downstream loss rate. The ACK RTT metric is not taken into account for this calculation.

In some situations, however, end-to-end RTT may prove insufficient and you may need to add ACK RTT as a performance criterion. This may be due to long session duration, when the frequency of RTT measurements is rather low.

To include client ACK RTT in the measurement algorithm, set the LOC_USE_CLI_ACK_RTT_TH property value to ON.

Configuration best practices summary

  • Make sure that network tiers reflect the division between the data center (LAN) and the client network (WAN/Internet).
  • Make sure that the site configuration is accurate and precise, covering all of the client networks.
  • If you prefer simpler calculations, use the fixed thresholds.
  • Change the cut-off thresholds to indicate problem importance.
    • If you set high values of the cut-off thresholds, the problem will have to be more severe to influence network performance.
    • If you set low values of the cut-off thresholds, the problem will have to be less severe to influence network performance and you will see yellow or red status icons on the reports more often.