H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 152)

11-17
Configuring Voice Tests
Do not perform voice tests on known ports, ports from 1 to 1023. Otherwise, the NQA test might fail or
the corresponding services of these ports might be unavailable.
Voice tests of an NQA test group are used to test voice over IP (VoIP) network status, and collect VoIP
network parameters so that users can adjust the network accordingly.
A voice test takes the following procedure:
1) The source (NQA client) sends voice packets of G.711 A-law, G.711 µ-law or G.729 A-law codec
type at regular intervals to the destination (NQA server).
2) The destination affixes a time stamp to each voice packet that it receives and then sends it back to
the source.
3) Upon receiving the packet, the source calculates results, such as the delay jitter and one-way delay
based on the packet time stamps. The statistics reflect network performance.
Voice test result also includes the following parameters that reflect VoIP network performance:
z Calculated Planning Impairment Factor (ICPIF)—Measures impairment to voice quality in a VoIP
network. It is decided by packet loss and delay. A higher value represents a lower service quality.
z Mean Opinion Scores (MOS)—A MOS value can be evaluated by using the ICPIF value, in the
range 1 to 5. A higher value represents a higher quality of a VoIP network.
The evaluation of voice quality depends on users’ tolerance to voice quality, which should be taken into
consideration. For users with higher tolerance to voice quality, use the advantage-factor command to
configure the advantage factor. When the system calculates the ICPIF value, this advantage factor is
subtracted to modify ICPIF and MOS values and both the objective and subjective factors are
considered when you evaluate the voice quality.
Configuration prerequisites
Voice tests require cooperation between the NQA server and the NQA client. Before you start voice
tests, configure a UDP listening service on the NQA server. For more information about UDP listening
service configuration, see Configuring the NQA Server .
Configuring voice tests
Follow these steps to configure voice tests:
To do… Use the command… Remarks
Enter system view system-view —
Enter NQA test group view
nqa entry admin-name
operation-tag
—
Configure the test type as voice
and enter test type view
type voice Required