2.2 Programming
Programming Guide
19
Parameter Descriptions
QoS Field Settings
The parameters below are used to set the ToS (Type of Service) field in the header of IP packets to control
QoS of VoIP communications.
Jitter buffer Settings
When voice signals are packetized and transmitted, individual packets can take different paths through the
network and arrive at the destination at varied timings. This is referred to as "jitter", and it can cause
degradation in speech quality. To compensate for jitter problems, the "jitter buffer" accumulates the packets
temporarily for processing.
The parameters below are used to adjust the size of the jitter buffer. However, in general, there is no need to
change the default values.
Parameter & Description
Default
Value Range
ToS
Specifies the value in the ToS field by a generic term.
For details, refer to "Detailed Explanations".
Priority: 0
0 to 7
Normal
Normal,
Monetary Cost,
Reliability,
Throughput,
Delay
DSCP
Specifies the value in the ToS field by a DSCP for DiffServ.
No default
0 to 63
HEX
Specifies the value in the ToS field by a hexadecimal number.
No default
00 to FF
Parameter
Default
Value Range
G.711/G.729A Jitter Buffer Minimum (ms)
10
10 × n (n = 1–40)
G.711/G.729A Jitter Buffer Maximum (ms)
400
10 × n (n = 1–40)
G.711/G.729A Jitter Buffer Default Value (ms)
10
10 × n (n = 1–40)
G.711/G.729A Jitter Buffer Adjustment Interval (s) 1-
5s
5
1 to 5
G.723.1 Jitter Buffer Minimum (ms)
30
30 × n (n = 1–40)
G.723.1 Jitter Buffer Maximum (ms)
1200
30 × n (n = 1–40)
G.723.1 Jitter Buffer Default value (ms)
30
30 × n (n = 1–40)
G.723.1 Jitter Buffer Adjustment Interval (s) 1-5s
5
1 to 5
