12-3
Input priority value dot1p-lp mapping dot1p-dp mapping
2 1 0
3 3 0
4 4 0
5 5 0
6 6 0
7 7 0
Table 12-3 The default dscp-lp, dscp-dp, dscp-dot1p, and dscp-exp priority mapping tables
Input priority value dscp-dp mapping dscp-dot1p mapping
DSCP Drop precedence (dp) 802.1p priority (dot1p)
0 to 7 0 0
8 to 15 0 1
16 to 23 0 2
24 to 31 0 3
32 to 39 0 4
40 to 47 0 5
48 to 55 0 6
56 to 63 0 7
Appendix C Introduction to Packet Precedences
IP Precedence and DSCP Values
Figure 12-1 ToS and DS fields
As shown in
Figure 12-1, the ToS field of the IP header contains eight bits, and the first three bits (0 to
2) represent IP precedence from 0 to 7. According to RFC 2474, the ToS field of the IP header 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.