Cisco Systems WSC4500X16SFP Manual De Usuario

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Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
Chapter 38      Configuring NetFlow
Configuring NetFlow Statistics Collection
Configuring the Minimum Mask of a Source-Prefix Aggregation Scheme
To configure the minimum mask of a source-prefix aggregation scheme, perform this task:
Monitoring and Maintaining Minimum Masks for Aggregation Schemes
To view the configured value of the minimum mask, use the following commands for each aggregation 
scheme, as needed:
Configuring NetFlow Aging Parameters
You can control when flows are purged from the software flow cache (and, if configured, reported 
through NDE) with the configuration aging parameters, Active and Inactive, of the ip flow-cache 
timeout
 command.
Active Aging specifies the period of time in which a flow should be removed from the software flow 
cache after the flow is created. Generally, this parameter is used to periodically notify external collection 
devices about active flows. This parameter operates independently of existing traffic on the flow. Active 
timeout settings tend to be on the order of minutes (default is 30min).
Inactive Aging specifies how long to wait before removing a flow after the last packet is seen. The 
Inactive parameter clears the flow cache of “stale” flows thereby preventing new flows from starving 
(due to lack of resources). Inactive timeout settings tend to be on the order of seconds (default is 15sec).
Command
Purpose
Step 1
Router(config)# ip flow-aggregation cache source-prefix
Configures the source-prefix aggregation 
cache.
Step 2
Router(config-flow-cache)# mask source minimum 
value
Specifies the minimum value for the source 
mask.
Command
Purpose
Router# show ip cache flow aggregation prefix
Displays the configured value of the 
minimum mask in the prefix aggregation 
scheme.
Router# show ip cache flow aggregation 
destination-prefix
Displays the configured value of the 
minimum mask in the destination-prefix 
aggregation scheme.
Router# show ip cache flow aggregation 
source-prefix
Displays the configured value of the 
minimum mask in the source-prefix 
aggregation scheme.