DSCP to Queue

The DSCP (IP Differentiated Services Code Point) to Queue page maps DSCP values to egress queues. The DSCP to Queue Table determines the egress queues of the incoming IP packets based on their DSCP values. The original VPT (VLAN Priority Tag) of the packet is unchanged.

By simply changing the DSCP to Queue mapping and the Queue schedule method and bandwidth allocation, it’s possible to achieve the desired quality of services in a network.

The DSCP to Queue mapping is applicable to IP packets if:

  • The device is in QoS Basic mode and DSCP is the trusted mode.

  • The device is in QoS Advanced mode and the packets belongs to flows that are DSCP trusted.

Non-IP packets are always classified to the best-effort queue.

The following tables describe the default DSCP to queue mapping for an 8-queue system where 8 is highest:

DSCP

63

55

47

39

31

23

15

7

Queue

8

7

6

5

4

3

2

1

DSCP

62

54

46

38

30

22

14

6

Queue

8

7

6

5

4

3

2

1

DSCP

61

53

45

37

29

21

13

5

Queue

8

7

6

5

4

3

2

1

DSCP

60

52

44

36

28

20

12

4

Queue

8

7

6

5

4

3

2

1

DSCP

59

51

43

35

27

19

11

3

Queue

8

7

6

5

4

3

2

1

DSCP

58

50

42

34

26

18

10

2

Queue

8

7

6

5

4

3

2

1

DSCP

57

49

41

33

25

17

9

1

Queue

8

7

6

5

4

3

2

1

DSCP

56

48

40

32

24

16

8

0

Queue

8

7

6

5

4

3

2

1

To map DSCP to queues, follow these steps:

Procedure

Step 1

Click Quality of Service > General > DSCP to Queue.

The DSCP to Queue page contains Ingress DSCP. It displays the DSCP value in the incoming packet and its associated class.

Step 2

Select the Output Queue (traffic forwarding queue) to which the DSCP value is mapped.

Step 3

Click Apply. The Running Configuration file is updated. Click Restore Defaults to restore the default settings.