Table Of Contents
DSCP and Precedence Values
Commonly Used DSCP Values
IP Precedence Values
DSCP and Precedence Values
This section provides the DSCP and precedence values used in QoS class maps and policy maps.
Commonly Used DSCP Values
Unless noted as a restriction, you can mark both incoming and outgoing packets.
Table 6-1 lists the commonly used DSCP values described in RFC 2475.
Table 6-1 Commonly Used DSCP Values
DSCP Value
|
Decimal Value
|
Meaning
|
Drop Probability
|
Equivalent IP Precedence Value
|
101 110
|
46
|
High Priority
Expedited Forwarding (EF)
|
N/A
|
101 - Critical
|
000 000
|
0
|
Best Effort
|
N/A
|
000 - Routine
|
001 010
|
10
|
AF11
|
Low
|
001 - Priority
|
001 100
|
12
|
AF12
|
Medium
|
001 - Priority
|
001 110
|
14
|
AF13
|
High
|
001 - Priority
|
010 010
|
18
|
AF21
|
Low
|
001 - Immediate
|
010 100
|
20
|
AF22
|
Medium
|
001 - Immediate
|
010 110
|
22
|
AF23
|
High
|
001 - Immediate
|
011 010
|
26
|
AF31
|
Low
|
011 - Flash
|
011 100
|
28
|
AF32
|
Medium
|
011 - Flash
|
011 110
|
30
|
AF33
|
High
|
011 - Flash
|
100 010
|
34
|
AF41
|
Low
|
100 - Flash Override
|
100 100
|
36
|
AF42
|
Medium
|
100 - Flash Override
|
100 110
|
38
|
AF43
|
High
|
100 - Flash Override
|
001 000
|
8
|
CS1
|
|
1
|
010 000
|
16
|
CS2
|
|
2
|
011 000
|
24
|
CS3
|
|
3
|
100 000
|
32
|
CS4
|
|
4
|
101 000
|
40
|
CS5
|
|
5
|
110 000
|
48
|
CS6
|
|
6
|
111 000
|
56
|
CS7
|
|
7
|
000 000
|
0
|
Default
|
|
|
101 110
|
46
|
EF
|
|
|
IP Precedence Values
Table 6-2 lists the RFC 791 precedence values from least to most important.
Table 6-2 Precedence Values
Value
|
Description
|
000 (0)
|
Routine or Best Effort
|
001 (1)
|
Priority
|
010 (2)
|
Immediate
|
011 (3)
|
Flash - mainly used for Voice Signaling or for Video.
|
100 (4)
|
Flash Override
|
101 (5)
|
Critical -mainly used for Voice RTP.
|
110 (6)
|
Internet
|
111 (7)
|
Network
|
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