Cisco Systems 3560X Manual De Usuario
42-91
Catalyst 3750-X and 3560-X Switch Software Configuration Guide
OL-21521-01
Chapter 42 Configuring IP Unicast Routing
Configuring Protocol-Independent Features
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. Equal-cost
routes are supported across switches in a stack.
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. Equal-cost
routes are supported across switches in a stack.
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.
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:
paths installed in a routing table from the default:
Use the no maximum-paths router configuration command to restore the default value.
Step 7
show cef linecard
[detail]
or
show cef linecard
[slot-number] [detail]
Display CEF-related interface information on a Catalyst
3560-X switch, or
3560-X switch, or
Display CEF-related interface information on a Catalyst
3750-X switch by stack member for all switches in the stack or
for the specified switch.
3750-X switch by stack member for all switches in the stack or
for the specified switch.
(Optional) For slot-number, enter the stack member switch
number.
number.
Step 8
show cef interface
[interface-id]
Display detailed CEF information for all interfaces or the
specified interface.
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
Command
Purpose
Step 1
configure terminal
Enter global configuration mode.
Step 2
router
{bgp | rip | ospf | eigrp}
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 for most IP routing
protocols, but only 1 for BGP.
table. The range is from 1 to 16; the default is 4 for most IP routing
protocols, but only 1 for BGP.
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.