Flexible NetFlow—IPv4 Unicast Flows

The Flexible Netflow—IPv4 Unicast Flows feature enables Flexible NetFlow to monitor IPv4 traffic.

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Information About Flexible NetFlow IPv4 Unicast Flows

Flexible NetFlow—IPv4 Unicast Flows Overview

This feature enables Flexible NetFlow to monitor IPv4 traffic.

How to Configure Flexible NetFlow IPv4 Unicast Flows

Creating 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 {ip | 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 the above step 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 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 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 {ip | 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.

Step 6

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

—

Step 7

collect interface {input | output }

Example:

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.

Step 8

Repeat the above step 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.

Configuring the Flow Exporter

Perform this required task to configure the flow exporter.


Note

Each flow exporter supports only one destination.

You can export to a destination using either an IPv4 or IPv6 address.

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. flow exporter exporter-name
  4. description description
  5. destination {ip-address | hostname } [vrf vrf-name ]
  6. dscp dscp
  7. source interface-type interface-number
  8. output-features
  9. template data timeout seconds
  10. transport udp udp-port
  11. ttl seconds
  12. end
  13. show flow exporter exporter-name
  14. show running-config flow exporter exporter-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

flow exporter exporter-name

Example:


Device(config)# flow exporter EXPORTER-1

Creates the flow exporter and enters Flexible NetFlow flow exporter configuration mode.

  • This command also allows you to modify an existing flow exporter.

Step 4

description description

Example:


Device(config-flow-exporter)# description Exports to the datacenter

(Optional) Configures a description to the exporter that will appear in the configuration and the display of the show flow exporter command.

Step 5

destination {ip-address | hostname } [vrf vrf-name ]

Example:


Device(config-flow-exporter)# destination 172.16.10.2

Specifies the IP address or hostname of the destination system for the exporter.

Note 

You can export to a destination using either an IPv4 or IPv6 address.

Step 6

dscp dscp

Example:


Device(config-flow-exporter)# dscp 63

(Optional) Configures differentiated services code point (DSCP) parameters for datagrams sent by the exporter.

  • The range for the dscp argument is from 0 to 63. Default: 0.

Step 7

source interface-type interface-number

Example:


Device(config-flow-exporter)# source ethernet 0/0

(Optional) Specifies the local interface from which the exporter will use the IP address as the source IP address for exported datagrams.

Step 8

output-features

Example:


Device(config-flow-exporter)# output-features

(Optional) Enables sending export packets using quality of service (QoS) and encryption.

Step 9

template data timeout seconds

Example:


Device(config-flow-exporter)# template data timeout 120

(Optional) Configures resending of templates based on a timeout.

  • The range for the seconds argument is 1 to 86400 (86400 seconds = 24 hours).

Step 10

transport udp udp-port

Example:


Device(config-flow-exporter)# transport udp 650

Specifies the UDP port on which the destination system is listening for exported datagrams.

  • The range for the udp-port argument is from 1 to 65536.

Step 11

ttl seconds

Example:


Device(config-flow-exporter)# ttl 15

(Optional) Configures the time-to-live (TTL) value for datagrams sent by the exporter.

  • The range for the seconds argument is from 1 to 255.

Step 12

end

Example:


Device(config-flow-exporter)# end

Exits flow exporter configuration mode and returns to privileged EXEC mode.

Step 13

show flow exporter exporter-name

Example:


Device# show flow exporter FLOW_EXPORTER-1

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

Step 14

show running-config flow exporter exporter-name

Example:


Device# show running-config flow exporter FLOW_EXPORTER-1

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

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. These record formats can be one of the predefined formats or a user-defined format. 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.

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 | {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 Action Purpose
Step 1

enable

Example:


> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:


# configure terminal

Enters global configuration mode.

Step 3

flow monitor monitor-name

Example:


(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:


(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:


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

Specifies the record for the flow monitor.

Step 6

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

Example:

(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:

    
(config-flow-monitor)# statistics packet protocol

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

    Step 9

    statistics packet size

    Example:

    
(config-flow-monitor)# statistics packet size

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

    Step 10

    exporter exporter-name

    Example:

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

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

    Step 11

    end

    Example:

    
(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:

    
# 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:

    
# 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 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

    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.

    Configuring and Enabling Flexible NetFlow with Data Export

    You must create a flow monitor to configure the types of traffic for which you want to export the cache data. You must enable the flow monitor by applying it to at least one interface to start exporting data. To configure and enable Flexible NetFlow with data export, perform this required task.

    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 remove a flow monitor from all of the interfaces to which you have applied it before you can modify the record format of the flow monitor.

    SUMMARY STEPS

    1. enable
    2. configure terminal
    3. flow monitor monitor-name
    4. record {record-name | netflow-original | netflow {ipv4 | ipv6 record [peer ] }]
    5. exporter exporter-name
    6. exit
    7. interface type number
    8. {ip | ipv6 } flow monitor monitor-name {input | output }
    9. end
    10. show flow monitor [[name ] monitor-name [cache [format {csv | record | table }]][statistics ]]

    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

    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 5

    exporter exporter-name

    Example:

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

    Specifies the name of an exporter that you created previously.

    Step 6

    exit

    Example:

    
Device(config-flow-monitor)# exit

    Exits Flexible NetFlow flow monitor 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 {input | output }

    Example:

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

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

    Step 9

    end

    Example:

    
Device(config-if)# end

    Exits interface configuration mode and returns to privileged EXEC mode.

    Step 10

    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. This will verify data export is enabled for the flow monitor cache.

    Configuration Examples for Flexible NetFlow IPv4 Unicast Flows

    Example: Configuring Multiple Export Destinations

    The following example shows how to configure multiple export destinations for Flexible NetFlow for IPv4 or IPv6 traffic.

    This sample starts in global configuration mode: 

    
!
flow exporter EXPORTER-1
 destination 172.16.10.2
 transport udp 90
 exit
!
flow exporter EXPORTER-2
 destination 172.16.10.3
 transport udp 90
 exit
!
flow record v4_r1
match ipv4 tos
match ipv4 protocol
match ipv4 source address
match ipv4 destination address
match transport source-port
match transport destination-port
collect counter bytes long
collect counter packets long
!
flow record v6_r1
match ipv6 traffic-class
match ipv6 protocol
match ipv6 source address
match ipv6 destination address
match transport source-port
match transport destination-port
collect counter bytes long
collect counter packets long
!

flow monitor FLOW-MONITOR-1
 record v4_r1
 exporter EXPORTER-2
 exporter EXPORTER-1
!
!
flow monitor FLOW-MONITOR-2
 record v6_r1
 exporter EXPORTER-2
 exporter EXPORTER-1
!
ip cef
!
interface GigabitEthernet1/0/0
 ip address 172.16.6.2 255.255.255.0
 ipv6 address 2001:DB8:2:ABCD::2/48
 ip flow monitor FLOW-MONITOR-1 input
 ipv6 flow monitor FLOW-MONITOR-2 input
!

    The following display output shows that the flow monitor is exporting data to the two exporters: 

    
Device# show flow monitor FLOW-MONITOR-1
Flow Monitor FLOW-MONITOR-1:
  Description:       User defined
  Flow Record:       v4_r1
  Flow Exporter:     EXPORTER-1
                     EXPORTER-2
  Cache:
    Type:              normal (Platform cache)
    Status:            allocated
    Size:              4096 entries / 311316 bytes
    Inactive Timeout:  15 secs
    Active Timeout:    1800 secs
    Update Timeout:    1800 secs

    Example: Configuring Flexible NetFlow Egress Accounting for IPv4 and IPv6 Traffic

    The following example shows how to configure Flexible NetFlow egress accounting for IPv4 and IPv6 traffic.

    This example starts in global configuration mode. 

    
!
flow record v4_r1
match ipv4 tos
match ipv4 protocol
match ipv4 source address
match ipv4 destination address
match transport source-port
match transport destination-port
collect counter bytes long
collect counter packets long
!
flow record v6_r1
match ipv6 traffic-class
match ipv6 protocol
match ipv6 source address
match ipv6 destination address
match transport source-port
match transport destination-port
collect counter bytes long
collect counter packets long
!
flow monitor FLOW-MONITOR-1
 record v4_r1
 exit
!
!
flow monitor FLOW-MONITOR-2
 record v6_r1
 exit
!
ip cef
ipv6 cef
!
interface GigabitEthernet0/0/0
 ip address 172.16.6.2 255.255.255.0
 ipv6 address 2001:DB8:2:ABCD::2/48
 ip flow monitor FLOW-MONITOR-1 output
 ipv6 flow monitor FLOW-MONITOR-2 output
!