7-5
Cisco 10000 Series Router Quality of Service Configuration Guide
OL-7433-09
Chapter 7 Marking Traffic
IP Precedence Marking
set ip precedence Command
To set the precedence value in a packet header, use the set ip precedence command in policy-map class
configuration mode. To remove the precedence value, use the no form of this command. By default, this
command is disabled.
set ip precedence prec-value
no set ip precedence prec-value
Syntax Description
set ip precedence Command History
Usage Guidelines for the set ip precedence Command
Bit Settings
After the precedence bits are set, other quality of service (QoS) features such as weighted fair queuing
(WFQ) and weighted random early detection (WRED) can then operate on the bit settings.
Precedence Value
The network can give priority (or some type of expedited handling) to marked traffic through the
application of weighted fair queuing (WFQ) or weighted random early detection (WRED) at points
downstream in the network. Typically, you set the precedence value at the edge of the network (or
administrative domain); data then is queued according to the specified precedence. WFQ can speed up
handling for certain precedence traffic at congestion points. WRED can ensure that certain precedence
traffic has lower loss rates than other traffic during times of congestion.
In Cisco IOS Release 12.3(7)XI, the router accepts the set precedence command without specifying the
ip keyword. However, you must specify the set
ip precedence command to set the precedence value in
a packet header.
ip Specifies that the match is for IPv4 packets only. You must specify this
keyword.
precedence prec-value Sets the precedence value. Valid values are from 0 to 7.
Cisco IOS Release Description
Release 12.0(17)SL The set ip precedence command was introduced on the PRE1.
Release 12.2(16)BX This command was introduced on the PRE2.
Release 12.2(28)SB This command was integrated in Cisco IOS Release 12.2(28)SB for the
PRE2.
Release 12.2(31)SB2 This command was introduced on the PRE3.
Release 12.2(33)SB This command was introduced on the PRE4.
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