H3C Technologies H3C WX6000 Series Access Controllers - Manual (Page 430)

44-3
Table 44-2 Description on DSCP precedence 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
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 the Layer 3
packet header does not need analysis but QoS must be assured at Layer 2.
Figure 44-2 An Ethernet frame with an 802.1Q tag header
As shown in the figure above, the 4-byte 802.1Q tag header contains a 2-byte Tag Protocol Identifier
(TPID) whose value is 8100 and a 2-byte Tag Control Information (TCI). TPID is a new class defined by
IEEE to indicate a packet with an 802.1Q tag.
Figure 44-3 describes the detailed contents of an 802.1Q
tag header.