QoS Setup page offers three parameters to characterize the WAN link. The default QoS setting is
disabled because these parameters must be correctly given according to the actual WAN speed.
4.1.13Enable QoS
1.
Click
Enable
.
2.
Enter the
WAN Uplink Speed
,
WAN Downlink Speed
, and
Uplink VoIP Reserved
(bandwidth).
3.
Click
Apply
.
For a popular 2M/256K ADSL program, the WAN uplink speed would be 256 and the WAN downlink
speed would be 2048. The Uplink VoIP reserved could be, say, 192 out of the total 256 kbps to allow 2
concurrent G.711 calls. Following is the table of WAN speed related to various codecs.
Codec Information
Bandwidth Calculations
Codec & Bit Rate
(Kbps)
Codec
Sample
Size
(Bytes)
Codec
Sample
Interval
(ms)
Mean
Opinion
Score
(MOS)
Voice
Payload
Size
(Bytes)
Voice
Payload
Size (ms)
Packets
Per
Second
(PPS)
Bandwidth
Required
(Kbps)
G.711 (64 Kbps)
80
10
4.1
160
20
50
87.2
G.729 (8 Kbps)
10
10
3.92
20
20
50
31.2
G.723.1 (6.3 Kbps)
24
30
3.9
24
30
34
21.9
G.723.1 (5.3 Kbps)
20
30
3.8
20
30
34
20.8
G.726 (32 Kbps)
20
5
3.85
80
20
50
55.2
G.726 (24 Kbps)
15
5
60
20
50
47.2
4.1.14Disable QoS
Click
Disable
, and then click
Apply
.
1.14 Virtual Server
You can configure IP PBX as a virtual server for remote users to access services such as the Web or
FTP at your local site via Public IP Addresses. With proper settings, IP PBX can automatically redirect
inbound traffic from WAN to local servers configured with private IP addresses. In other words,
depending on the requested service (TCP/UDP) port number, the IP PBX redirects the external
service request to the appropriate internal server (located at one of your LAN's Private IP Address).
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