- The transmission queue lengths are tailored for each QoS class.
Precedence
- Real-time traffic is given precedence over best effort traffic.
Typing CLI command # ip qos show will output, among other information, the QoS Policy Table:
If having QOS-4 license installed in the VSAT:
QOS Policy Table
Grp Cls CrM Pri QLength Drop Timeout Description
0 0 0 0 400000 0 120 Best Effort
1 1 1 1 15000 1 120 VoIP Audio
2 1 1 2 4000 1 120 VoIP Signaling
3 2 1 5 500000 1 120 VIC Video
4 2 1 4 50000 1 120 VIC Audio
5 2 1 3 10000 1 120 VIC Signaling
6 3 0 6 400000 0 120 Critical Data
If not having the QOS-4 license installed the output will be:
QOS Policy Table
Grp Cls CrM Pri QLength Drop Timeout Description
0 0 0 0 400000 0 120 Best Effort
1 1 1 1 15000 1 120 VoIP Audio
2 1 1 2 4000 1 120 VoIP Signaling
The parameters in the QoS Policy Table are not user configurable.
11.1 Configuring QoS for the Return Link
In order to determine the QoS group an IP packet belongs to, the VSAT uses a multi-field classifier. This
multi-field classifier is used to perform a look-up in a classification table for all IP packets that shall be
transmitted on the Return Link. This table can store up to 15 different masks that the IP packets will be
matched to.
The following parameters in the IP header can be used for doing the MFC classification:
IP source address
IP destination address
DSCP / TOS
Protocol type
TCP/UDP source port number
TCP/UDP destination port number
Additionally the Ethernet User Priority as per IEEE 802.1Q can be used for QoS classification. Refer to section 18.6
for more details on mapping the Ethernet User Priority to a Return Link QoS class.
The MFC in the VSAT can also be used to set the DSCP field in the IP header.
The format of the QoS module of the MFC table is:
The index parameter is used to uniquely identify an entry in the classification table and decides the order
in which the classification table is searched. When an IP packet is to be classified, the classification table
is searched from index 0 and upward. If a match is found, the search is stopped and the IP packet is
thereafter handled with the QoS Group for this entry in the classification table. If a match is not found for
an IP packet it will be treated as best effort traffic.
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