Flexible Netflow Layer 2 Fields
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Flexible Netflow--Layer 2 Fields

Last Updated: November 16, 2012

The Flexible Netflow Layer 2 Fields feature enables collecting statistics for Layer 2 fields such as MAC addresses and virtual LAN (VLAN) IDs from traffic.

Finding Feature Information

Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Information About Flexible Netflow Layer 2 Fields

Flexible Netflow--Layer 2 Fields Overview

The Flexible Netflow--Layer 2 Fields feature enables collecting statistics for Layer 2 fields such as MAC addresses and virtual LAN (VLAN) IDs from traffic.

How to Configure Flexible Netflow Layer 2 Fields

Configuring a Customized Flow Record

Perform this task to configure a customized flow record.

Customized flow records are used to analyze traffic data for a specific purpose. A customized flow record must have at least one match criterion for use as the key field and typically has at least one collect criterion for use as a nonkey field.

There are hundreds of possible permutations of customized flow records. This task shows the steps that are used to create one of the possible permutations. Modify the steps in this task as appropriate to create a customized flow record for your requirements.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    flow record record-name

4.    description description

5.    match {ipv4 | ipv6}{destination | source} address

6.    Repeat Step 5 as required to configure additional key fields for the record.

7.    collect interface {input | output}

8.    Repeat Step 7 as required to configure additional nonkey fields for the record.

9.    end

10.    show flow record record-name

11.    show running-config flow record record-name


DETAILED STEPS
 Command or ActionPurpose
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 record record-name


Example:

Device(config)# flow record FLOW-RECORD-1

 

Creates a flow record and enters Flexible NetFlow flow record configuration mode.

  • This command also allows you to modify an existing flow record.
 
Step 4
description description


Example:

Device(config-flow-record)# description Used for basic traffic analysis

 

(Optional) Creates a description for the flow record.

 
Step 5
match {ipv4 | ipv6}{destination | source} address


Example:

Device(config-flow-record)# match ipv4 destination address

 

Configures a key field for the flow record.

Note    This example configures the IPv4 destination address as a key field for the record. For information about the other key fields available for the match ipv4 command, and the other match commands that are available to configure key fields, refer to the Cisco IOS Flexible NetFlow Command Reference .
 
Step 6
Repeat Step 5 as required to configure additional key fields for the record.  

--

 
Step 7
collect interface {input | output}


Example:

Device(config-flow-record)# collect interface input

 

Configures the input interface as a nonkey field for the record.

Note    This example configures the input interface as a nonkey field for the record. For information on the other collect commands that are available to configure nonkey fields, refer to the Cisco IOS Flexible NetFlow Command Reference.
 
Step 8
Repeat Step 7 as required to configure additional nonkey fields for the record.  

--

 
Step 9
end


Example:

Device(config-flow-record)# end

 

Exits Flexible NetFlow flow record configuration mode and returns to privileged EXEC mode.

 
Step 10
show flow record record-name


Example:

Device# show flow record FLOW_RECORD-1

 

(Optional) Displays the current status of the specified flow record.

 
Step 11
show running-config flow record record-name


Example:

Device# show running-config flow record FLOW_RECORD-1

 

(Optional) Displays the configuration of the specified flow record.

 

Creating a Customized Flow Monitor

Perform this required task to create a customized 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.

An advanced user can create a customized format using the flow record command.

Before You Begin

If you want to use a customized record instead of using one of the Flexible NetFlow predefined records, you must create the customized record before you can perform this task.

If you want to add a flow exporter to the flow monitor for data export, you must create the exporter before you can complete this task.


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. For information about the ip flow monitor command, refer to the Cisco IOS Flexible NetFlow Command Reference.


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.    cache {entries number | timeout {active | inactive | update} seconds | type {immediate | normal | permanent}}

7.    Repeat Step 6 as required to finish modifying the cache parameters for this flow monitor.

8.    statistics packet protocol

9.    statistics packet size

10.    exporter exporter-name

11.    end

12.    show flow monitor [[name] monitor-name [cache [format {csv | record | table}]] [statistics]]

13.    show running-config flow monitor monitor-name


DETAILED STEPS
 Command or ActionPurpose
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 ipv4 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 FLOW-RECORD-1

 

Specifies the record for the flow monitor.

 
Step 6
cache {entries number | timeout {active | inactive | update} seconds | type {immediate | normal | permanent}}


Example:

Device(config-flow-monitor)# cache type normal

 

(Optional) Modifies the flow monitor cache parameters such as timeout values, number of cache entries, and the cache type.

  • The values for the keywords associated with the timeout keyword have no effect when the cache type is set to immediate.
 
Step 7
Repeat Step 6 as required to finish modifying the cache parameters for this flow monitor.  

--

 
Step 8
statistics packet protocol


Example:

Device(config-flow-monitor)# statistics packet protocol

 

(Optional) Enables the collection of protocol distribution statistics for Flexible NetFlow monitors.

 
Step 9
statistics packet size


Example:

Device(config-flow-monitor)# statistics packet size

 

(Optional) Enables the collection of size distribution statistics for Flexible NetFlow monitors.

 
Step 10
exporter exporter-name


Example:

Device(config-flow-monitor)# exporter EXPORTER-1

 

(Optional) Specifies the name of an exporter that was created previously.

 
Step 11
end


Example:

Device(config-flow-monitor)# end

 

Exits Flexible NetFlow flow monitor configuration mode and returns to privileged EXEC mode.

 
Step 12
show flow monitor [[name] monitor-name [cache [format {csv | record | table}]] [statistics]]


Example:

Device# show flow monitor FLOW-MONITOR-2 cache

 

(Optional) Displays the status and statistics for a Flexible NetFlow flow monitor.

 
Step 13
show running-config flow monitor monitor-name


Example:

Device# show running-config flow monitor FLOW_MONITOR-1

 

(Optional) Displays the configuration of the specified flow monitor.

 

Applying a Flow Monitor to an Interface

Before it can be activated, a flow monitor must be applied to at least one interface. Perform this required task to activate a flow monitor.

SUMMARY STEPS

1.    enable

2.    configure terminal

3.    interface type number

4.    {ip | ipv6} flow monitor monitor-name {input | output}

5.    Repeat Steps 3 and 4 to activate a flow monitor on any other interfaces in the device over which you want to monitor traffic.

6.    end

7.    show flow interface type number

8.    show flow monitor name monitor-name cache format record


DETAILED STEPS
 Command or ActionPurpose
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
interface type number


Example:

Device(config)# interface GigabitEthernet 0/0/0

 

Specifies an interface and enters interface configuration mode.

 
Step 4
{ip | ipv6} flow monitor monitor-name {input | output}

Example:

Device(config-if)# ip flow monitor FLOW-MONITOR-1 input

 

Activates a flow monitor that was created previously by assigning it to the interface to analyze traffic.

 
Step 5
Repeat Steps 3 and 4 to activate a flow monitor on any other interfaces in the device over which you want to monitor traffic.  

--

 
Step 6
end


Example:

Device(config-if)# end

 

Exits interface configuration mode and returns to privileged EXEC mode.

 
Step 7
show flow interface type number


Example:

Device# show flow interface GigabitEthernet 0/0/0

 

Displays the status of Flexible NetFlow (enabled or disabled) on the specified interface.

 
Step 8
show flow monitor name monitor-name cache format record


Example:

Device# show flow monitor name FLOW_MONITOR-1 cache format record

 

Displays the status, statistics, and flow data in the cache for the specified flow monitor.

 

Configuration Examples for Flexible Netflow Layer 2 Fields

Example: Configuring Flexible NetFlow for Monitoring MAC and VLAN Statistics

The following example shows how to configure Flexible NetFlow for monitoring MAC and VLAN statistics.

This sample starts in global configuration mode: 

!
 flow record LAYER-2-FIELDS-1
 match ipv4 source address
 match ipv4 destination address
 match datalink dot1q vlan output
 match datalink mac source address input
 match datalink mac source address output
 match datalink mac destination address input
 match flow direction
!
 exit
!
!
flow monitor FLOW-MONITOR-4
 record LAYER-2-FIELDS-1
 exit
!
ip cef
!
interface GigabitEthernet0/0/1
 ip address 172.16.6.2 255.255.255.0
 ip flow monitor FLOW-MONITOR-1 input
!

Additional References

Related Documents

Related Topic

Document Title

Cisco IOS commands

Cisco IOS Master Command List, All Releases

Flexible NetFlow conceptual information and configuration tasks

Flexible NetFlow Configuration Guide

Flexible NetFlow commands

Cisco IOS Flexible NetFlow Command Reference

Standards/RFCs

Standard

Title

No new or modified standards/RFCs are supported by this feature.

--

MIBs

MIB

MIBs Link

None

To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs

Technical Assistance

Description

Link

The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password.

http://www.cisco.com/cisco/web/support/index.html

Feature Information for Flexible NetFlow--Layer 2 Fields

The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.

Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.

Table 1Feature Information for Flexible NetFlow--Layer 2 Fields

Feature Name

Releases

Feature Information

Flexible NetFlow--Layer 2 Fields

12.2(33)SRE

12.4(22)T

Cisco IOS XE Release 3.2SE

Enables collecting statistics for Layer 2 fields such as MAC addresses and virtual LAN (VLAN) IDs from traffic.

Support for this feature was added for Cisco 7200 and 7300 Network Processing Engine (NPE) series routers in Cisco IOS Release 12.2(33)SRE.

The following commands were introduced or modified:

collect datalink dot1q vlan , collect datalink mac, match datalink dot1q vlan, match datalink mac.

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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.

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