Copyright © 2006 – STM Norway AS
Publication no. 101557, Rev. T, November 3
th
, 2006
Page 45
The second alternative has the advantage that the audio and the audio-signalling are protected from
fluctuations in video traffic. The third alternative has the additional advantage of giving extra protection
to the ViC signalling. However, to use option two and three, the terminal’s QoS classificator must be
able to distinguish between the video, audio, and signalling components of the Vic in order to separate
them into different QoS groups.
8.4
DSCP and DiffServ
The following DSCP values are recommended to use on equipment connected to the STM SatLink
Terminal:
Traffic
Recommended DSCP
Recommended QoS group
Best Effort
0 (000000)
0
Critical Data
26 (AF31; 011010)
6
ViC bulk
46 (EF; 101110) if VoIP is not in
use
47 (101111) otherwise
3
ViC video
46 (EF; 101110) if VoIP is not in
use
47 (101111) otherwise
3
ViC audio+ signalling
39 (100111)
4
ViC audio
39 (100111)
4
ViC signalling
35 (100011)
5
VoIP bulk
46 (EF; 101110)
1
VoIP audio
46 (EF; 101110)
1
VoIP signalling
43 (101011)
2
Unconditional packet dropping
3 (000011)
n.a.
Recommended mapping to support standardised DiffServ compliance:
DSCP
Recommended QoS group
Comment
0 (000000)
0
Best effort
56 (111000)
6
Requires forwarding precedence
48 (110000)
6
Requires forwarding precedence
Other, not specifically treated
0
Best effort
Recommended mapping for support of the standardised AF PHB group, using AF class 3 as example:
DSCP
Recommended QoS group
Comment
26 (AF31; 011010)
6
AF Class 3 low drop precedence
28 (AF32, 011100)
0
AF Class 3 medium drop
precedence
30 (AF33, 011110)
0
AF Class 3 high drop precedence
Recommended mapping for support of the standardised EF PHB:
DSCP
Recommended QoS group
Comment
46 (EF; 101110)
1
This is an applicable mapping
for constant rate real-time
applications like VoIP