H3C S5120-SI Series

1-6
DSCP value (decimal) DSCP value (binary) Description
26 011010 af31
28 011100 af32
30 011110 af33
34 100010 af41
36 100100 af42
38 100110 af43
8 001000 cs1
16 010000 cs2
24 011000 cs3
32 100000 cs4
40 101000 cs5
48 110000 cs6
56 111000 cs7
0 000000 be (default)
2) 802.1p precedence
802.1p precedence lies in Layer 2 packet headers and is applicable to occasions where Layer 3 header
analysis is not needed and QoS must be assured at Layer 2.
Figure 1-4 An Ethernet frame with an 802.1Q tag header
As shown in
Figure 1-4, the 4-byte 802.1Q tag header consists of the tag protocol identifier (TPID, two
bytes in length), whose value is 0x8100, and the tag control information (TCI, two bytes in length).
Figure 1-5 presents the format of the 802.1Q tag header.
Figure 1-5 802.1Q tag header