Appendix b introduction to packet precedences, Ip precedence and dscp values – H3C Technologies H3C WX3000E Series Wireless Switches User Manual
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Appendix B Introduction to packet precedences
IP precedence and DSCP values
Figure 17 ToS and DS fields
As shown in
, the ToS field in the IP header contains eight bits. The first three bits (0 to 2)
represent IP precedence from 0 to 7. According to RFC 2474, the ToS field is redefined as the
differentiated services (DS) field, where a DSCP value is represented by the first six bits (0 to 5) and is in
the range 0 to 63. The remaining two bits (6 and 7) are reserved.
Table 10 Description on IP precedence
IP precedence (decimal)
IP precedence (binary)
Description
0 000
Routine
1 001
priority
2 010
immediate
3 011
flash
4 100
flash-override
5 101
critical
6 110
internet
7 111
network
Table 11 Description on DSCP values
DSCP value (decimal)
DSCP value (binary)
Description
46 101110
ef
10 001010
af11
12 001100
af12
14 001110
af13
18 010010
af21
20 010100
af22
22 010110
af23
26 011010
af31