MAPPING LAYER 3/4 PRIORITIES TO COS VALUES

Mapping DSCP Priority

The DSCP is six bits wide, allowing coding for up to 64 different forwarding behaviors. The DSCP replaces the ToS bits, and it retains backward compatibility with the three precedence bits so that non-DSCP compliant, ToS-enabled devices, will not conflict with the DSCP mapping. Based on network policies, different kinds of traffic can be marked for different kinds of forwarding. The DSCP default values are defined in the following table. Note that DSCP values that are not specified are mapped to CoS value 0.

IP DSCP Value

CoS Value

0

0

 

 

8

1

 

 

10, 12, 14, 16

2

 

 

18, 20, 22, 24

3

 

 

26, 28, 30, 32, 34, 36

4

 

 

38, 40, 42

5

 

 

48

6

 

 

46, 56

7

 

 

Fields and Attributes

IP Precedence/DSCP Priority Status – Selects IP Precedence, DSCP, or disables both priority services.

DSCP Priority Table – Shows the DSCP Priority to CoS map.

Class of Service Value – Maps a CoS value to the selected DSCP Priority value. Note that “0” represents low priority and “7” represents high priority.

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SMC Networks SMC7724M/VSW manual Mapping Dscp Priority