Configuring Layer 4 Load Balancing; Verifying The Cef Database And Measuring Flows - Cisco CRS-1 - Carrier Routing System Router Troubleshooting Manual

Troubleshooting Layer 3 or Layer 4 Load Balancing

Configuring Layer 4 Load Balancing

By default, the load balancing algorithm uses Layer 3 information only. This section describes how to
configure load balancing to use both Layer 3 and Layer 4 information. Use the setting that is appropriate
for your own system. Layer 4 distributes loads more evenly over the interfaces because it considers more
packet parameters when defining unique flows.
SUMMARY STEPS
1.
2.
3.
DETAILED STEPS
Command or Action
Step 1
configure
Example:
RP/0/RP0/CPU0:router# configure
Step 2
RP/0/RP0/CPU0:Router(config)# cef
load-balancing fields [L3 |L4]
Example:
RP/0/RP0/CPU0:router(config)# cef
load-balancing fields L4
Step 3
end

Verifying the CEF Database and Measuring Flows

Cisco Express Forwarding uses the path information in the Cisco Express Forwarding (CEF) database
to balance traffic over multiple links. For this reason, confirming proper CEF load balancing begins with
confirming the contents of the CEF database.
SUMMARY STEPS
1.
2.
3.
Cisco IOS XR Troubleshooting Guide for the Cisco CRS-1 Router
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configure
cef load-balancing fields L4
end
show cef ipv4 [prefix [mask]] | interface-type interface-path-id] [detail] [location node-id]
show cef [ipv4 | ipv6] exact-route source-address destination-address [protocol type]
[source-port source-port] [destination-port destination-port] [ingress-interface type
interface-path-id] [policy-class value] [detail | location node-id]
show interfaces [type interface-path-id | all | local | location node-id] [accounting | brief | detail |
summary]
Chapter 13
Purpose
Enters global configuration mode.
Configures the fields of the IP header that the hash
algorithm uses when balancing flows across parallel links.
Ends the configuration process. Enter yes at the prompt to
commit the changes.
Troubleshooting Load Balancing
OL-21483-02