Configuring the voice operation
![[CAUTION: ]](images/caution.png) | CAUTION: To ensure successful voice operations and avoid affecting existing services, do not perform the operations on well-known ports from 1 to 1023. | |
The voice operation measures VoIP network performance.
The voice operation works as follows:
The NQA client sends voice packets at sending intervals to the destination device (NQA server).
The voice packets are of one of the following codec types:
G.711 A-law.
G.711 µ-law.
G.729 A-law.
The destination device time stamps each voice packet it receives and sends it back to the source.
Upon receiving the packet, the source device calculates the jitter and one-way delay based on the timestamp.
The following parameters that reflect VoIP network performance can be calculated by using the metrics gathered by the voice operation:
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.
Mean Opinion Scores (MOS)—A MOS value can be evaluated by using the ICPIF value, in the range of 1 to 5. A higher value represents a higher service quality.
The evaluation of voice quality depends on users' tolerance for voice quality. For users with higher tolerance for voice quality, use the advantage-factor command to set an advantage factor. When the system calculates the ICPIF value, it subtracts the advantage factor to modify ICPIF and MOS values for voice quality evaluation.
The voice operation requires both the NQA server and the NQA client. Before you perform a voice operation, configure a UDP listening service on the NQA server. For more information about UDP listening service configuration, see "Configuring the NQA server."
The voice operation cannot repeat.
To configure the voice operation:
Step | Command | Remarks |
|---|---|---|
1. Enter system view. | system-view | N/A |
2. Create an NQA operation and enter NQA operation view. | nqa entry admin-name operation-tag | By default, no NQA operations exist. |
3. Specify the voice type and enter its view. | type voice | N/A |
4. Specify the destination address of voice packets. | destination ip ip-address | By default, no destination IP address is configured. The destination IP address must be the same as the IP address of the listening service on the NQA server. |
5. Specify the destination port of voice packets. | destination port port-number | By default, no destination port number is configured. The destination port number must be the same as the port number of the listening service on the NQA server. |
6. (Optional.) Specify the codec type. | codec-type { g711a | g711u | g729a } | By default, the codec type is G.711 A-law. |
7. (Optional.) Set the advantage factor for calculating MOS and ICPIF values. | advantage-factor factor | By default, the advantage factor is 0. |
8. (Optional.) Specify the source IP address of voice packets. | source ip ip-address | By default, the packets take the primary IP address of the output interface as their source IP address. The source IP address must be the IP address of a local interface, and the interface must be up. Otherwise, no voice packets can be sent out. |
9. (Optional.) Specify the source port number of voice packets. | source port port-number | By default, no source port number is specified. |
10. (Optional.) Set the payload size for each voice packet. | data-size size | By default, the voice packet size varies by codec type. The default packet size is 172 bytes for G.711A-law and G.711 µ-law codec type, and 32 bytes for G.729 A-law codec type. |
11. (Optional.) Specify the payload fill string for voice packets. | data-fill string | The default payload fill string is the hexadecimal string 00010203040506070809. |
12. (Optional.) Set the number of voice packets to be sent in a voice probe. | probe packet-number packet-number | The default setting is 1000. |
13. (Optional.) Set the interval for sending voice packets. | probe packet-interval interval | The default setting is 20 milliseconds. |
14. (Optional.) Specify how long the NQA client waits for a response from the server before it regards the response times out. | probe packet-timeout timeout | The default setting is 5000 milliseconds. |
![[NOTE: ]](images/note.png) | NOTE: Use the display nqa result or display nqa statistics command to verify the voice operation. The display nqa history command does not display the voice operation results or statistics. | |