Information Technology Reference
In-Depth Information
Comparison of Switching Mechanisms
Table 2-3 compares the different switching methods available in Cisco routers.
Table 2-3
Comparison of Switching Path Support in Cisco Routers for Transit Packets
Configurations
to Enable the
Switching Path
Low to
Medium
Range
*
Switching
Path
Cisco 7200/
7100 series
Cisco 7500
series
Cisco 12000
series
Process
switching
no ip route-cache
under an interface
Ye s
Ye s
Ye s
N o
Fast switching
ip route-cache
under
an interface
Yes (the
default)
**
Yes (the
default)
Ye s
N o
Optimum
switching
***
ip route-cache
optimum
under an
interface
No
Yes
Yes
No
Distributed
optimum
switching
ip route-cache
distributed
under a
VIP interface
No
No
Yes, with
VIPs
No
Ye s
****
NetFlow
switching
ip route-cache flow
under an interface
Ye s
Ye s
Ye s
CEF
ip route-cache cef
under an interface
ip cef
in global
configuration
Ye s
Yes
Yes (the
default for IP)
No
dCEF
ip cef distributed
in
global configuration
No
No
Yes, with
VIPs
Yes (the default);
cannot be
disabled globally
*
Includes all other router platforms not specifically listed here.
**
The default switching path for a platform may vary between different IOS releases and is dependent on the hardware support
and the type of protocol to be switched.
***
Optimum switching and distributed optimum switching are no longer supported for IOS releases beginning with Release 12.0.
****
For collecting traffic statistics only; not for packet switching.
Several commands display which path the interface uses and how the traffic is being
switched:
•
show ip interface
•
show interface statistics
•
show cef interface
•
show interface switching
