Mapping DSCP Priority
The DSCP is six bits wide, allowing coding for up to 64 differ ent forw arding
behaviors. The DSCP replaces the ToS bits, but 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 kin ds o f
traffic can be marked for different kinds of forwarding. The DSCP default va lues a re
defined in the following table. Note that all the DSCP values that are not spe cified
are mapped to CoS value 0.
Table 13-4 Mapping DSCP Priority
IP DSCP Value CoS Value
00
81
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
Command Attributes
• DSCP Priority Table – Sho ws the DSC P Priori ty to CoS map.
• Class of Se rv ic e Va lue – Maps a CoS value to the sele ct ed D SCP Pr i orit y v alue.
Note that “0” represents low priority and “7” represent high prior ity.
Note: IP DSCP settin gs apply to al l int erfaces.
Web
– Click Priority, IP DSCP Priority. Select an entry from the DSCP table, enter a
value in the Class of Service Value field, then click Apply.
Figure 13-7 IP DSCP Priority

13-10

Class of Service

13