User's Manual

Technical Notes – QoS Features on BES50

Priority

Index

CoS Value IP DSCP

0 0 0

1 1 10

2 2 12

3 3 14

4 4 18

5 5 20

6 6 22

7 7 26

8 0 28

9 1 30

10 2 34

11 3 36

12 4 38

13 5 46

14 6 0

15 7 0

Table 4: BES50GE Priority Index to CoS and IP DSCP Mapping

A word of caution when IP DSCP based traffic prioritization is enabled. Since the DSCP value is 6 bits and there

are only 8 CoS/priority value, enabling IP DSCP remarking may alter IP DSCP to an undesirable value. The

following table combines the default DSCP to CoS mapping with Table 4: BES50GE Priority Index to CoS and

IP DSCP Mapping.

Ingress IP DSCP Value CoS Value Priority Index Egress IP DSCP Value

0 0 0 0

8 1 1 10

10, 12, 14, 16 2 2 12

18, 20, 22, 24 3 3 14

26, 28, 30, 32, 34, 36 4 4 18

38, 40, 42 5 5 20

48 6 6 22

46, 56 7 7 25

E.g.

If IP DSCP traffic prioritization is enabled and the incoming IP packet with DSCP value of 36 does not match

any one of the ACL rules, BES50GE will map the traffic to the traffic class 4 with a corresponding priority index

value 4. When IP DSCP re-marking is enabled at the egress port, BES50 will map the priority index value 4 to IP

DSCP value 18 and re-mark the outgoing IP packet with this value.