Help us improve your experience.

Let us know what you think.

Do you have time for a two-minute survey?

Navigation
Guide That Contains This Content
[+] Expand All
[-] Collapse All

    Viewing Mean Opinion Score for an RFC 2544-Based Benchmarking Test

    Mean Opinion Score (MOS) is a metric used within the telecommunications industry to assess voice quality. The value range for the MOS metric is:

    • 1 = bad
    • 2 = poor
    • 3 = fair
    • 4 = good
    • 5 = excellent

    Typically, the MOS for Voice over IP is in the range of 3.5 to 4.2. The highest score that most codecs can achieve is in the range of 4.2 to 4.4 because even a perfect connection is affected by the compression algorithms of the codec.

    Currently, the Junos Space Release 13.1P1 MOS is based on the E-model ITU-T G.107 Recommendation and implements a Latency test only.

    R Factor is a voice quality metric describing the segment of the call that is carried over this RTP session expressed as an integer in the range from 0 to 100 dB. A value of 94 corresponds to "toll quality", and values of 50 or less are regarded as unusable. This metric includes the effects of delay. A value of 127 indicates that this parameter is unavailable. statistics

    Ext. R Factor , which signifies the external R factor, is a voice quality metric describing the segment of the call that is carried over a network segment external to the RTP segment, such as a cellular network. Its values are interpreted in the same manner as for the RTPR factor. This metric includes the effects of delay and relates to the outward voice path from the VoIP termination for which this metrics block applies.


    To obtain the MOS for an RFC2544 test:

    1. From the View selector, select Device View.

      The workspaces that are applicable to this view are displayed.

    2. From the Junos Space user interface, click the Monitor icon on the Connectivity Services Director banner.

      The functionalities that you can configure in this mode are displayed in the task pane.

    3. From the View pane, click the plus sign (+) beside the My Network item in the View pane to expand the tree and select the device node you want for which you want to manage the RFC2544 test.

      The device type selected within the device model tree is highlighted.

    4. Click the RFC2544 Tests tab on the right pane. The RFC2544 Tests page is displayed.

      The following fields are displayed in a table at the top of the page:

      • Initiatior—Name of the device configured as the generator or initiator of frames for the test
      • Name—Name of the configured RFC 2544 test that contains the parameters of the test
      • Reflector—Name of the device configured as the reflector for the test
      • Test Status—Status of the RFC 2544-based test, such as whether the test is started or not, is in progress, or has been completed
      • Start/Stop—Commence or terminate a RFC 2544-based test

      Tip: Apart from viewing test results an RFC 2544-based test from Monitor mode of Device View for a particular device, you can also create, start, or stop an RFC 2544-based test from Monitor mode of Service View for a particular service configured on a device. To administer such tests for a service, select Service View from the View selector, click the Monitor icon on the Connectivity Services Director banner, and from the View pane, drill-down the Network Services > OAM > RFC2544 Tests tree and select an RFC 2544 test. The RFC2544 Tests tab is displayed on the right pane. The following fields are displayed on the page:

      • Name—Name of the configured RFC 2544 test that contains the parameters of the test
      • Initiator/Reflector—Name of the device configured as the initiator or reflector for the test
      • Test Status—Status of the RFC 2544-based test, such as whether the test is started or not, is in progress, or has been completed
      • Start/Stop—Commence or terminate a RFC 2544-based test
    5. From the list of tests in the table, select the check box beside the test for which you want to view results.

      The RFC2544 Tests page displays information in four panels or widgets:

      • Throughput (top left panel)
      • Latency (bottom left panel)
      • Frameloss (top right panel)
      • Back Back (bottom right panel)

      Each widget contains the Status field, which indicates whether the test is currently in progress or has been terminated.

      Click Refresh (rotating circle icon) at the top of the monitor to update and display the contents of the table. From the Time Interval drop-down box, select 1 Hour, 8 Hours, 1 Day, 1 Week, 1 Month, 3 Months, 6 Months, 1 Year, or Custom to specify the duration for which the data polled from devices needs to be displayed. If you select the Custom option, the Time range popup dialog box is displayed. Specify the date from the calendar, and select the Time From (Start time in the 24-hour time format of collection of data), and Time To (End time in the 24-hour time format of collection of data). Click OK to save the settings. Else, click Cancel to discard the configuration.

      Each of the four widgets includes three tabs. If you click on a tab, you can view detailed illustration of the test result for the corresponding test profile. If a parameter was not configured in the RFC2544 test profile, the corresponding panel displays the message, “Test case not configured for this profile.”


    6. In the RFC2544 Test window, click the Latency Test Summary Results tab.

      The MOS metric appears in the far right column of the results table.


    7. Click on the View MOS Results link in the status bar.

      The View MOS Results window appears.


      The following table provides the abbreviation, unit of measure, default value, and permitted value range for each parameter in the View MOS Results window.

      Parameter

      Abbreviation

      Unit

      Default Value

      Value Range

      Electric Circuit Noise

      dBm0p

      Noise floor at the receive side

      Nfor

      dBmp

      –64

      Room noise at the send side

      Ps

      db(A)

      35

      35 through 85

      Room noise at the receive side

      Pr

      dB(A)

      35

      35 through 85

      Send loudness rating

      SLR

      dB

      +8

      0 through +18

      Receive loudness rating

      RLR

      dB

      +2

      –5 though

      Sidetone masking rating

      STMR

      dB

      15

      10 through 20

      D-Value of telephone, receive side

      Dr

      3

      –3 through +3

      Listener sidetone rating

      LSTR

      dB

      18

      13 through 23

      D-Value of telephone, send side

      Ds

      3

      –3 through +3

      Mean one-way delay of the echo path

      T

      ms

      0

      0 through 500

      Absolute delay in echo-free connections

      Ta

      ms

      0

      0 through 500

      Round-trip delay in a 4-wire loop

      Tr

      ms

      0

      0 through 1000

      Talker echo loudness rating

      TELR

      dB

      65

      5 through 65

      Weighted echo path loss

      WEPL

      dB

      110

      5 through 110

      Number of quantization distortion units

      qdu

      1

      1 through 14

      Equipment impairment factor

      Ie

      0

      0 through 40

      Packet-loss robustness factor

      Bpl

      4.3

      4.3 through 40

      Random packet-loss probability

      Ppl

      %

      0

      0 through 20

      Burst ratio

      BurstR

      1

      1 through 8

      Advantage factor

      A

      0

      0 through 20

    Modified: 2016-03-14