121
{
G.729 A-law.
2.
The destination device takes a time stamp to each voice packet it receives and sends it back to
the source.
3.
Upon receiving the packet, the source device calculates the jitter and one-way delay based on
the time stamp.
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 configure the 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 "
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 operation is
created.
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.) Specify 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, no source IP address is
specified.
The source IP address must be the
IP address of a local interface, and
the interface must be up. Otherwise,
