Configuring The Number Of Equal-Cost Routing Paths - Cisco WS-C3020 Software Configuration Manual

Chapter 34 Configuring IP Unicast Routing
Beginning in privileged EXEC mode, follow these steps to enable CEF globally and on an interface for
software-forwarded traffic if it has been disabled:
Command
Step 1
configure terminal
Step 2 ip cef
Step 3 interface interface-id
Step 4 ip route-cache cef
Step 5
end
Step 6 show ip cef
Step 7 show cef linecard[detail]
Step 8
show cef interface [interface-id]
Step 9
show adjacency
Step 10 copy running-config startup-config

Configuring the Number of Equal-Cost Routing Paths

When a router has two or more routes to the same network with the same metrics, these routes can be
thought of as having an equal cost. The term parallel path is another way to see occurrences of equal-cost
routes in a routing table. If a router has two or more equal-cost paths to a network, it can use them
concurrently. Parallel paths provide redundancy in case of a circuit failure and also enable a router to
load balance packets over the available paths for more efficient use of available bandwidth.
Even though the router automatically learns about and configures equal-cost routes, you can control the
maximum number of parallel paths supported by an IP routing protocol in its routing table. Although the
switch software allows a maximum of 32 equal-cost routes, the switch hardware will never use more than
16 paths per route.
Beginning in privileged EXEC mode, follow these steps to change the maximum number of parallel
paths installed in a routing table from the default:
Command
Step 1 configure terminal
Step 2 router rip
Step 3
maximum-paths maximum
Step 4
end
Step 5 show ip protocols
Step 6 copy running-config startup-config
Use the no maximum-paths router configuration command to restore the default value.
OL-8915-03
Purpose
Enter global configuration mode.
Enable CEF operation.
Enter interface configuration mode, and specify the Layer 3
interface to configure.
Enable CEF on the interface for software-forwarded traffic.
Return to privileged EXEC mode.
Display the CEF status on all interfaces.
Display CEF-related interface information
Display detailed CEF information for all interfaces or the
specified interface.
Display CEF adjacency table information.
(Optional) Save your entries in the configuration file.
Purpose
Enter global configuration mode.
Enter router configuration mode.
Set the maximum number of parallel paths for the protocol routing
table. The range is from 1 to 16; the default is 4.
Return to privileged EXEC mode.
Verify the setting in the Maximum path field.
(Optional) Save your entries in the configuration file.
Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide
Configuring Protocol-Independent Features
34-29