Configuring a Flow Monitor

Samplers are applied to an interface in conjunction with a flow monitor. You must create a flow monitor to configure the types of traffic that you want to analyze before you can enable sampling. Perform this required task to configure a flow monitor.

Each flow monitor has a separate cache assigned to it. Each flow monitor requires a record to define the contents and layout of its cache entries. The record format can be one of the predefined record formats, or an advanced user may create his or her own record format using the collect and match commands in Flexible NetFlow flow record configuration mode.

Note	You must use the no ip flow monitor command to remove a flow monitor from all of the interfaces to which you have applied it before you can modify the parameters for the record command on the flow monitor.

SUMMARY STEPS

1.    enable


2.    configure terminal


3.    flow monitor monitor-name


4.    description description


5.    record {record-name | netflow-original | netflow {ipv4 | ipv6} record [peer]}


6.    end

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Device> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Device# configure terminal	Enters global configuration mode.
Step 3	flow monitor monitor-name Example: Device(config)# flow monitor FLOW-MONITOR-1	Creates a flow monitor and enters Flexible NetFlow flow monitor configuration mode. This command also allows you to modify an existing flow monitor.
Step 4	description description Example: Device(config-flow-monitor)# description Used for basic traffic analysis	(Optional) Creates a description for the flow monitor.
Step 5	record {record-name | netflow-original | netflow {ipv4 | ipv6} record [peer]} Example: Device(config-flow-monitor)# record netflow ipv4 original-input	Specifies the record for the flow monitor.
Step 6	end Example: Device(config-flow-monitor)# end	Exits Flexible NetFlow flow monitor configuration mode and returns to privileged EXEC mode.

Perform this required task to configure and enable a flow sampler.

SUMMARY STEPS

1.    enable


2.    configure terminal


3.    sampler sampler-name


4.    description description


5.    mode {random} 1 out-of window-size


6.    exit


7.    interface type number


8.    {ip | ipv6} flow monitor monitor-name [[sampler] sampler-name] {input | output}

9.    end


10.    show sampler sampler-name

DETAILED STEPS

	Command or Action	Purpose
Step 1	enable Example: Device> enable	Enables privileged EXEC mode. Enter your password if prompted.
Step 2	configure terminal Example: Device# configure terminal	Enters global configuration mode.
Step 3	sampler sampler-name Example: Device(config)# sampler SAMPLER-1	Creates a sampler and enters sampler configuration mode. This command also allows you to modify an existing sampler.
Step 4	description description Example: Device(config-sampler)# description Sample at 50%	(Optional) Creates a description for the flow sampler.
Step 5	mode {random} 1 out-of window-size Example: Device(config-sampler)# mode random 1 out-of 2	Specifies the sampler mode and the flow sampler window size. The range for the window-size argument is from .
Step 6	exit Example: Device(config-sampler)# exit	Exits sampler configuration mode and returns to global configuration mode.
Step 7	interface type number Example: Device(config)# interface GigabitEthernet 0/0/0	Specifies an interface and enters interface configuration mode.
Step 8	{ip | ipv6} flow monitor monitor-name [[sampler] sampler-name] {input | output} Example: Device(config-if)# ip flow monitor FLOW-MONITOR-1 sampler SAMPLER-1 input	Assigns the flow monitor and the flow sampler that you created to the interface to enable sampling.
Step 9	end Example: Device(config-if)# end	Exits interface configuration mode and returns to privileged EXEC mode.
Step 10	show sampler sampler-name Example: Device# show sampler SAMPLER-1	Displays the status and statistics of the flow sampler that you configured and enabled.

Displaying the Status and Statistics of the Flow Sampler Configuration

Device> enable
Device#

Device# show sampler SAMPLER-1
Sampler SAMPLER-1:
  ID:             2
  Description:    Sample at 50%
  Type:           random
  Rate:           1 out of 2
  Samples:        2482
  Requests:       4964
  Users (1):
    flow monitor FLOW-MONITOR-1 (ip,Et0/0,I  2482 out of 4964

Additional References

Feature Information for Flexible NetFlow Flow Sampling