Specifications

IP Switching Commands
ip cef
ISW-34
Cisco IOS IP Switching Command Reference
May 2008
ip cef
To enable Cisco Express Forwarding (CEF) on the route processor card, use the ip cef command in
global configuration mode. To disable CEF, use the no form of this command.
ip cef [distributed]
no ip cef [distributed]
Syntax Description
Defaults CEF is disabled by default, excluding these platforms:
CEF is enabled on the Cisco 7100 series router.
CEF is enabled on the Cisco 7200 series router.
CEF is enabled on the Cisco 7500 series Internet router.
Distributed CEF is enabled on the Cisco 6500 series router
Distributed CEF is enabled on the Cisco 12000 series Internet router.
Command Modes Global configuration
Command History
Usage Guidelines The ip cef command is not available on the Cisco 12000 series because that router series operates only
in dCEF mode.
CEF is advanced Layer 3 IP switching technology. CEF optimizes network performance and scalability
for networks with dynamic, topologically dispersed traffic patterns, such as those associated with
web-based applications and interactive sessions.
distributed (Optional) Enables distributed CEF (dCEF) operation. Distributes CEF
information to line cards. Line cards perform express forwarding.
Release Modification
11.1 CC This command was introduced.
12.2 The default for Cisco 7200 series routers was changed from disabled to
enabled.
12.2(11)T This command was integrated into Cisco IOS Release 12.2(11)T and
implemented on the following platforms: Cisco IAD2420 series,
Cisco
2600 series, Cisco 3620 routers, Cisco 3640 routers, Cisco 3660
routers, Cisco 3700 series routers, and Cisco MC3810 multiservice access
concentrators.
12.2(28)SB This command was integrated into Cisco IOS Release 12.2(28)SB.
12.2(33)SRA This command was integrated into Cisco IOS Release 12.2(33)SRA.
12.2SX This command is supported in the Cisco IOS Release 12.2SX train. Support
in a specific 12.2SX release of this train depends on your feature set,
platform, and platform hardware.