Cisco WS-C3020 - Configuring the Number of Equal-Cost Routing Paths

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Cisco Catalyst Blade Switch 3020 for HP Software Configuration Guide
OL-8915-03
Chapter 34 Configuring IP Unicast Routing
Configuring Protocol-Independent Features
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:
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:
Use the no maximum-paths router configuration command to restore the default value.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
ip cef Enable CEF operation.
Step 3
interface interface-id Enter interface configuration mode, and specify the Layer 3
interface to configure.
Step 4
ip route-cache cef Enable CEF on the interface for software-forwarded traffic.
Step 5
end Return to privileged EXEC mode.
Step 6
show ip cef Display the CEF status on all interfaces.
Step 7
show cef linecard[detail] Display CEF-related interface information
Step 8
show cef interface [interface-id] Display detailed CEF information for all interfaces or the
specified interface.
Step 9
show adjacency Display CEF adjacency table information.
Step 10
copy running-config startup-config (Optional) Save your entries in the configuration file.
Command Purpose
Step 1
configure terminal Enter global configuration mode.
Step 2
router rip Enter router configuration mode.
Step 3
maximum-paths maximum Set the maximum number of parallel paths for the protocol routing
table. The range is from 1 to 16; the default is 4.
Step 4
end Return to privileged EXEC mode.
Step 5
show ip protocols Verify the setting in the Maximum path field.
Step 6
copy running-config startup-config (Optional) Save your entries in the configuration file.