Comtech EF Data VMS v3.12.x Vipersat - Manual (Page 245)

Chapter 4 - Configuring Network Modems 4-27
MN/22156, rev 12 Network
The modem/router will prioritize the traffic based upon the DSCP Class Selec-
tor Precedence.
Note: All traffic that does not have the DSCP Class Selector Precedence
defined (000 000) will be placed in the Default Queue and have a Prece-
dence of 0.
Assured Forwarding DSCP
Another implementation of DiffServ uses all 6 bits of the DSCP to define
Assured Forwarding, as shown in table 4-3.
The Service Rate setting (kbps) is the minimum bandwidth for the transmit data
rate.
Assured Forwarding DiffServ defines four service levels (Class 1 through Class
4) and also uses the last three bits of the DSCP to define the drop probability or
Drop Precedence Level: Low (010), Medium (100), or High (110). The Drop
Precedence determines which packets will most likely be dropped during peri-
ods of over congestion, similar to Weighted Random Early Detection (WRED).
Precedence 2 010 000 6
Precedence 3 011 000 5
Precedence 4 100 000 4
Precedence 5 101 000 3
Precedence 6 110 000 2
Precedence 7 111 000 1
Table 4-3 Assured Forwarding, DSCP
DiffServ Type Class Selector DSCP
Modem/Router
Priority
Assured Forwarding – Class 1 Precedence 1 001 xx0 7
Assured Forwarding – Class 2 Precedence 1 010 xx0 7
Assured Forwarding – Class 3 Precedence 1 011 xx0 7
Assured Forwarding – Class 4 Precedence 1 100 xx0 7
Table 4-2 DiffServ Code Points (DSCP)
Class Selector DSCP
Modem/Router
Priority
NOTE