H3C Technologies H3C WX6000 Series Access Controllers User 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.
describes the detailed contents of an 802.1Q
tag header.