2.2 Programming
18
Programming Guide
Parameter Descriptions
QoS Field Settings
Jitter Buffer 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.
For more information about QoS, refer to "A1.4 QoS (Quality of Service)" of the VoIP Gateway Card
Getting Started. For the actual setting values, consult your network administrator.
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
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
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)
