set precedence
To set the precedence value in the IP header, use the
set precedence
command in policy map class
configuration mode. To leave the precedence value unchanged, use the
no
form of this command.
set precedence [tunnel] value
no set precedence [tunnel] value
Syntax Description
(Optional) Sets the IP precedence on the outer IP header.
tunnel
Number or name that sets the precedence bits in the IP header. Range is from 0 to 7. Reserved
keywords can be specified instead of numeric values.
Table 3: IP Precedence Values and Names,
on page 22
describes the reserved keywords.
value
Command Default
No default behavior or values
Command Modes
Policy map class configuration
Command History
Modification
Release
This command was introduced.
Release 6.0
Usage Guidelines
Precedence can be set using a number or corresponding name. After IP Precedence bits are set, other QoS
services can then operate on the bit settings.
The
set precedence
command is supported only in the ingress direction. Unconditional precedence marking
is supported.
The network gives priority (or some type of expedited handling) to the marked traffic. IP precedence can be
set at the edge of the network (or administrative domain) and have queueing act on it thereafter.
The mapping from keywords such as 0 (routine) and 1 (priority) to a precedence value is useful only in some
instances. That is, the use of the precedence bit is evolving. You can define the meaning of a precedence value
by enabling other features that use the value. In the case of high-end Internet QoS, IP precedences can be used
to establish classes of service that do not necessarily correspond numerically to better or worse handling in
the network.
Task ID
Operations
Task
ID
read,
write
qos
Examples
This example shows how to set the IP precedence to 5 (critical) for packets that match the access
control list named customer1:
RP/0/RP0/CPU0:router(config)#
class-map class1
RP/0/RP0/CPU0:router(config-cmap)#
match access-group ipv4 customer1
RP/0/RP0/CPU0:router(config-cmap)#
exit
Modular QoS Command Reference for Cisco NCS 5500 Series and Cisco NCS 540 Series Routers
35
QoS Classification Commands
set precedence