H3C Technologies H3C S3600 Series Switches User Manual
Page 735
1-5
IP Precedence (decimal)
IP Precedence (binary)
Description
5 101
critical
6 110
internet
7 111
network
In a network providing differentiated services, traffics are grouped into the following four classes, and
packets are processed according to their DSCP values.
z
Expedited Forwarding (EF) class: In this class, packets can be forwarded regardless of link share
of other traffic. The class is suitable for preferential services with low delay, low packet loss ratio,
low jitter, and assured bandwidth (such as virtual leased line);
z
Assured forwarding (AF) class: This class is further divided into four subclasses (AF1/2/3/4) and a
subclass is further divided into three drop priorities, so the AF service level can be segmented. The
QoS rank of the AF class is lower than that of the EF class;
z
Class selector (CS) class: This class comes from the IP ToS field and includes eight subclasses;
z
Best Effort (BE) class: This class is a special class without any assurance in the CS class. The AF
class can be degraded to the BE class if it exceeds the limit. Current IP network traffic belongs to
this class by default.
Table 1-3 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