Configuring Flexible NetFlow

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.

Prerequisites for Flexible NetFlow

The following are prerequisites for your Flexible NetFlow configuration:

  • You must configure a source interface. If you do not configure a source interface, the exporter will remain in a disabled state.

  • You must configure a valid record name for every flow monitor.

  • You must enable IPv6 routing to export the flow records to an IPv6 destination server.

  • You must configure IPFIX export protocol for the flow exporter to export netflow records in IPFIX format.

  • You are familiar with the Flexible NetFlow key fields as they are defined in the following commands in the Cisco IOS Flexible NetFlow Command Reference :

    • match datalink—Datalink (layer2) fields

    • match flow—Flow identifying fields

    • match interface—Interface fields

    • match ipv4—IPv4 fields

    • match ipv6—IPv6 fields

    • match transport—Transport layer fields

    • match wireless—Wireless fields

  • You are familiar with the Flexible NetFlow non key fields as they are defined in the following commands in the Cisco IOS Flexible NetFlow Command Reference :

    • collect counter—Counter fields

    • collect flow—Flow identifying fields

    • collect interface—Interface fields

    • collect timestamp—Timestamp fields

    • collect transport—Transport layer fields

    • collect wireless—Wireless fields

IPv4 Traffic

  • The networking device must be configured for IPv4 routing.

  • One of the following must be enabled on your router and on any interfaces on which you want to enable Flexible NetFlow: Cisco Express Forwarding or distributed Cisco Express Forwarding.

IPv6 Traffic

  • The networking device must be configured for IPv6 routing.

  • One of the following must be enabled on your router and on any interfaces on which you want to enable Flexible NetFlow: Cisco Express Forwarding IPv6 or distributed Cisco Express Forwarding.

Restrictions for Flexible NetFlow

The following are restrictions for Flexible NetFlow:

  • Traditional NetFlow (TNF) accounting is not supported.

  • Flexible NetFlow version 9 and version 10 export formats are supported. However, if you have not configured the export protocol, version 9 export format is applied by default.

  • Microflow policing feature shares the NetFlow hardware resource with FNF.

  • Only one flow monitor per interface and per direction is supported .

  • Layer 2, IPv4, and IPv6 traffic types are supported. Multiple flow monitors of different traffic types can be applied for a given interface and direction. Multiple flow monitors of same traffic type cannot be applied for a given interface and direction.

  • Layer 2, VLAN, WLAN and Layer 3 interfaces are supported, but the switch does not support SVI and tunnels.

  • The following NetFlow table sizes are supported:

    Trim Level

    Ingress NetFlow Table

    Egress NetFlow Table

    LAN Base

    Not supported

    Not supported

    IP Base

    8 K

    16 K

    IP Services

    8 K

    16 K

  • Depending on the switch type, a switch will have one or two forwarding ASICs. The capacities listed in the above table are on a per-ASIC basis.

  • The switch can support either one or two ASICs. Each ASIC has 8K ingress and 16 K egress entries, whereas each TCAM can handle up to 6K ingress and 12K egress entries.

  • The NetFlow tables are on separate compartments and cannot be combined. Depending on which ASIC processed the packet, the flows will be created in the table in the corresponding ASIC.

  • NetFlow hardware implementation supports four hardware samplers. You can select a sampler rate from 1 out of 2 to 1 out of 1024. Only random sampling mode is supported.

  • NetFlow hardware uses hash tables internally. Hash collisions can occur in the hardware. Therefore, in spite of the internal overflow Content Addressable Memory (CAM), the actual NetFlow table utilization could be about 80 percent.

  • Depending on the fields that are used for the flow, a single flow could take two consecutive entries. IPv6 flows also take two entries. In these situations, the effective usage of NetFlow entries is half the table size, which is separate from the above hash collision limitation.

  • The switch supports up to 15 flow monitors.

  • SSID-based NetFlow accounting is supported. SSID is treated in a manner similar to an interface. However, certain fields are not supported such as user ID .

  • The NetFlow software implementation supports distributed NetFlow export, so the flows are exported from the same switch in which the flow was created.

  • Ingress flows are present in the ASIC that first received the packets for the flow. Egress flows are present in the ASIC from which the packets actually left the switch set up.

  • The reported value for the bytes count field (called “bytes long”) is Layer-2-packet-size—18 bytes. For classic Ethernet traffic (802.3), this will be accurate. For all other Ethernet types, this field will not be accurate. Use the "bytes layer2” field, which always reports the accurate Layer 2 packet size. For information about supported Flexible NetFlow fields, see Supported Flexible NetFlow Fields.

  • Configuration of IPFIX exporter on an AVC flow monitor is not supported.

  • Flexible NetFlow export is not supported on the Ethernet management port, Gi0/0.

  • When a flow record has only Source Group Tag (SGT) and Destination Group Tag (DGT) fields (or only either of the two) and if both the values are not applicable, then a flow will still be created with zero values for SGT and DGT. The flow records are expected to include source and destination IP addresses, along with SGT and DGT fields.

  • The flow monitor with flow record, that contains the CTS field, cannot be attached on the WLAN (SSID).

  • When QoS marked packet is received on an interface which has NetFlow configured on the egress direction, the QoS value of the packet will be captured by the collector. However, when the packet is received on an interface which has NetFlow configured on the ingress direction, the QoS value of the packet will not be captured by the collector.

Information About Flexible Netflow

Flexible NetFlow Overview

Flexible NetFlow uses flows to provide statistics for accounting, network monitoring, and network planning.

A flow is a unidirectional stream of packets that arrives on a source interface and has the same values for the keys. A key is an identified value for a field within the packet. You create a flow using a flow record to define the unique keys for your flow.

The switch supports the Flexible NetFlow feature that enables enhanced network anomalies and security detection. Flexible NetFlow allows you to define an optimal flow record for a particular application by selecting the keys from a large collection of predefined fields.

All key values must match for the packet to count in a given flow. A flow might gather other fields of interest, depending on the export record version that you configure. Flows are stored in the Flexible NetFlow cache.

You can export the data that Flexible NetFlow gathers for your flow by using an exporter and export this data to a remote system such as a Flexible NetFlow collector. The Flexible NetFlow collector can use an IPv4 or IPv6 address.

You define the size of the data that you want to collect for a flow using a monitor. The monitor combines the flow record and exporter with the Flexible NetFlow cache information.

Wireless Flexible NetFlow Overview

The wireless Flexible NetFlow infrastructure supports the following:

  • Flexible NetFlow Version 9.0
  • User-based rate limiting
  • Microflow policing
  • Voice and video flow monitoring
  • Reflexive access control list (ACL)

Microflow Policing and User-Based Rate Limiting

Microflow policing associates a 2-color 1-rate policer and related drop statistics to each flow present in the NetFlow table. When the flow mask comprises all packet fields, this functionality is known as microflow policing. When the flow mask comprises either source or destination only, this functionality is known as user-based rate limiting.

Voice and Video Flow Monitoring

Voice and video flows are full flow mask-based entries. The ASIC provides the flexibility to program the policer parameters, share policers across multiple flows and rewrite the IP address and Layer 4 port numbers of these flows.


Note

For dynamic entries, the NetFlow engine will use the policer parameters that are derived for the flow based on the policy (ACL/QoS-based policies). Dynamic entries cannot share policer across multiple flows.

Reflexive ACL

Reflexive ACLs allow IP packets to be filtered based on upper-layer session information. The ACLs allow outbound traffic and limit inbound traffic in response to the sessions that originate inside the trusted network. The reflexive ACLs are transparent to the filtering mechanism until a data packet that matches the reflexive entry activates it. At this time, a temporary ACL entry is created and added to the IP-named access lists. The information obtained from the data packet to generate the reflexive ACL entry is permit/deny bit, the source IP address and port, the destination IP address, port, and the protocol type. During reflexive ACL entry evaluation, if the protocol type is either TCP or UDP, then the port information must match exactly. For other protocols, there is no port information to match. After this ACL is installed, the firewall is then opened for the reply packets to pass through. At this time, a potential hacker could have access to the network behind the firewall. To narrow this window, an idle timeout period can be defined. However, in the case of TCP, if two FIN bits or an RST is detected, the ACL entry can be removed.

Related Tasks
Configuring WLAN to Apply Flow Monitor in IPV4 and IPv6 Input/Output Direction
Related References
Example: Configuring IPv4 Flexible NetFlow in WLAN (Ingress Direction)
Example: Configuring IPv6 and Transport Flag Flexible NetFlow in WLAN (Egress Direction)
Example: Configuring IPv6 Flexible NetFlow in WLAN (Both Ingress and Egress Directions)

Benefits of Flexible NetFlow

Flexible NetFlow allows the flow to be user defined. The benefits of Flexible NetFlow include:

  • High-capacity flow recognition, including scalability and aggregation of flow information.

  • Enhanced flow infrastructure for security monitoring and dDoS detection and identification.

  • New information from packets to adapt flow information to a particular service or operation in the network. The flow information available will be customizable by Flexible NetFlow users.

  • Extensive use of Cisco’s flexible and extensible NetFlow Version 9 and version 10 export formats. With version 10 export format, support for variable length field for the wireless client's SSID is available.

  • A comprehensive IP accounting feature that can be used to replace many accounting features, such as IP accounting, Border Gateway Protocol (BGP) Policy Accounting, and persistent caches.

  • Support for ingress and egress NetFlow accounting.

  • Support for full flow accounting and sampled NetFlow accounting.

Flexible NetFlow allows you to understand network behavior with more efficiency, with specific flow information tailored for various services used in the network. The following are some example applications for a Flexible NetFlow feature:

  • Flexible NetFlow enhances Cisco NetFlow as a security monitoring tool. For instance, new flow keys can be defined for packet length or MAC address, allowing users to search for a specific type of attack in the network.

  • Flexible NetFlow allows you to quickly identify how much application traffic is being sent between hosts by specifically tracking TCP or UDP applications by the class of service (CoS) in the packets.

  • The accounting of traffic entering a Multiprotocol Label Switching (MPLS) or IP core network and its destination for each next hop per class of service. This capability allows the building of an edge-to-edge traffic matrix.

The figure below is an example of how Flexible NetFlow might be deployed in a network.

Figure 1. Typical Deployment for Flexible NetFlow

Flexible NetFlow Components

Flexible NetFlow consists of components that can be used together in several variations to perform traffic analysis and data export. The user-defined flow records and the component structure of Flexible NetFlow facilitates the creation of various configurations for traffic analysis and data export on a networking device with a minimum number of configuration commands. Each flow monitor can have a unique combination of flow record, flow exporter, and cache type. If you change a parameter such as the destination IP address for a flow exporter, it is automatically changed for all the flow monitors that use the flow exporter. The same flow monitor can be used in conjunction with different flow samplers to sample the same type of network traffic at different rates on different interfaces. The following sections provide more information on Flexible NetFlow components:

Flow Records

In Flexible NetFlow a combination of key and nonkey fields is called a record. Flexible NetFlow records are assigned to Flexible NetFlow flow monitors to define the cache that is used for storing flow data. Flexible NetFlow includes several predefined records that can help you get started using Flexible NetFlow.

A flow record defines the keys that Flexible NetFlow uses to identify packets in the flow, as well as other fields of interest that Flexible NetFlow gathers for the flow. You can define a flow record with any combination of keys and fields of interest. The switch supports a rich set of keys. A flow record also defines the types of counters gathered per flow. You can configure 64-bit packet or byte counters. The switch enables the following match fields as the defaults when you create a flow record:

  • match datalink—Layer 2 attributes

  • match flow direction — Specifies a match to the fields identifying the direction of flow.

  • match interface—Interface attributes

  • match ipv4—IPv4 attributes

  • match ipv6—IPv6 attributes

  • match transport—Transport layer fields

  • match wireless—Wireless fields

Related Tasks
Creating a Flow Record

NetFlow Predefined Records

Flexible NetFlow includes several predefined records that you can use to start monitoring traffic in your network. The predefined records are available to help you quickly deploy Flexible NetFlow and are easier to use than user-defined flow records. You can choose from a list of already defined records that may meet the needs for network monitoring. As Flexible NetFlow evolves, popular user-defined flow records will be made available as predefined records to make them easier to implement.

The predefined records ensure backward compatibility with your existing NetFlow collector configurations for the data that is exported. Each of the predefined records has a unique combination of key and nonkey fields that offer you the built-in ability to monitor various types of traffic in your network without customizing Flexible NetFlow on your router.

Two of the predefined records (NetFlow original and NetFlow IPv4/IPv6 original output), which are functionally equivalent, emulate original (ingress) NetFlow and the Egress NetFlow Accounting feature in original NetFlow, respectively. Some of the other Flexible NetFlow predefined records are based on the aggregation cache schemes available in original NetFlow. The Flexible NetFlow predefined records that are based on the aggregation cache schemes available in original NetFlow do not perform aggregation. Instead each flow is tracked separately by the predefined records.

User-Defined Records

Flexible NetFlow enables you to define your own records for a Flexible NetFlow flow monitor cache by specifying the key and nonkey fields to customize the data collection to your specific requirements. When you define your own records for a Flexible NetFlow flow monitor cache, they are referred to as user-defined records. The values in nonkey fields are added to flows to provide additional information about the traffic in the flows. A change in the value of a nonkey field does not create a new flow. In most cases the values for nonkey fields are taken from only the first packet in the flow. Flexible NetFlow enables you to capture counter values such as the number of bytes and packets in a flow as nonkey fields.

Flexible NetFlow adds a new Version 9 export format field type for the header and packet section types. Flexible NetFlow will communicate to the NetFlow collector the configured section sizes in the corresponding Version 9 export template fields. The payload sections will have a corresponding length field that can be used to collect the actual size of the collected section.

Flexible NetFlow Match Parameters

The following table describes Flexible NetFlow match parameters. You must configure at least one of the following match parameters for the flow records.

Table 1 Match Parameters

Command

Purpose

match datalink {dot1q | ethertype | mac | vlan }

Specifies a match to datalink or Layer 2 fields. The following command options are available:

  • dot1q—Matches to the dot1q field.

  • ethertype—Matches to the ethertype of the packet.

  • mac—Matches the source or destination MAC fields.

  • vlan—Matches to the VLAN that the packet is located on (input or output).

match flow direction

Specifies a match to the flow identifying fields.

match interface {input | output}

Specifies a match to the interface fields. The following command options are available:

  • input—Matches to the input interface.

  • output—Matches to the output interface.

match ipv4 {destination | protocol | source | tos | ttl | version}

Specifies a match to the IPv4 fields. The following command options are available:

  • destination—Matches to the IPv4 destination address-based fields.

  • protocol—Matches to the IPv4 protocols.

  • source—Matches to the IPv4 source address based fields.

  • tos—Matches to the IPv4 Type of Service fields.

  • ttl—Matches to the IPv4 Time To Live fields.

  • version—Matches to the IP version from the IPv4 header.

match ipv6 {destination | hop-limit | protocol | source | traffic-class | version }

Specifies a match to the IPv6 fields. The following command options are available:

  • destination—Matches to the IPv6 destination address-based fields.

  • hop-limit—Matches to the IPv6 hop limit fields.

  • protocol—Matches to the IPv6 payload protocol fields.

  • source—Matches to the IPv6 source address based fields.

  • traffic-class—Matches to the IPv6 traffic class.

  • version—Matches to the IP version from the IPv6 header.

match transport {destination-port | igmp | icmp | source-port}

Specifies a match to the Transport Layer fields. The following command options are available:

  • destination-port—Matches to the transport destination port.

  • icmp—Matches to ICMP fields, including ICMP IPv4 and IPv6 fields.

  • igmp—Matches to IGMP fields.

  • source-port—Matches to the transport source port.

match wireless ssid

Specifies a match to the Service Set IDentifier (SSID) field, which identifies the 802.11 (Wi-Fi) network used.

Flexible NetFlow Collect Parameters

The following table describes the Flexible NetFlow collect parameters.

Table 2 Collect Parameters

Command

Purpose

collect counter { bytes { layer2 { long } | long } | packets { long } }

Collects the counter fields total bytes and total packets.

collect interface {input | output}

Collects the fields from the input or output interface.

collect timestamp absolute {first | last}

Collects the fields for the absolute time the first packet was seen or the absolute time the most recent packet was last seen (in milliseconds).

collect transport tcp flags

Collects the following transport TCP flags:

  • ack—TCP acknowledgement flag

  • cwr—TCP congestion window reduced flag

  • ece—TCP ECN echo flag

  • fin—TCP finish flag

  • psh—TCP push flag

  • rst—TCP reset flag

  • syn—TCP synchronize flag

  • urg—TCP urgent flag

Note   

On the switch, you cannot specify which TCP flag to collect. You can only specify to collect transport TCP flags. All TCP flags will be collected with this command.

collect wireless ap mac address

Collects the MAC addresses of the access points that the wireless client is associated with.

Flow Exporters

Flow exporters export the data in the flow monitor cache to a remote system, such as a server running NetFlow collector, for analysis and storage. Flow exporters are created as separate entities in the configuration. Flow exporters are assigned to flow monitors to provide data export capability for the flow monitors. You can create several flow exporters and assign them to one or more flow monitors to provide several export destinations. You can create one flow exporter and apply it to several flow monitors.

NetFlow Data Export Format Version 10 (IPFIX)

Internet Protocol Flow Information Export (IPFIX) or version 10 is an Export Protocol that collects and exports predefined or user defined flow records. IPFIX is an IETF standard based on NetFlow version 9. The IPFIX format maintains the same principles of separate templates and records as NetFlow version 9. It supports variable length field for SSID of the wireless clients. For IPFIX exporting protocol, the default destination port is 4739, DSCP value is 0, and TTL is 255.

NetFlow Data Export Format Version 9

The basic output of NetFlow is a flow record. Several different formats for flow records have evolved as NetFlow has matured. The most recent evolution of the NetFlow export format is known as Version 9. The distinguishing feature of the NetFlow Version 9 export format is that it is template-based. Templates provide an extensible design to the record format, a feature that should allow future enhancements to NetFlow services without requiring concurrent changes to the basic flow-record format. Using templates provides several key benefits:

  • Third-party business partners who produce applications that provide collector or display services for NetFlow do not have to recompile their applications each time a new NetFlow feature is added. Instead, they should be able to use an external data file that documents the known template formats.

  • New features can be added to NetFlow quickly without breaking current implementations.

  • NetFlow is “future-proofed” against new or developing protocols because the Version 9 format can be adapted to provide support for them.

NetFlow Version 9 export format provides the following features and functionality:

  • Variable field specification format

  • Support for IPv4 or IPv6 destination address export

  • More efficient network utilization

The Version 9 export format consists of a packet header followed by one or more template flow or data flow sets. A template flow set provides a description of the fields that will be present in future data flow sets. These data flow sets may occur later within the same export packet or in subsequent export packets. Template flow and data flow sets can be intermingled within a single export packet, as illustrated in the figure below.

Figure 2. Version 9 Export Packet

NetFlow Version 9 will periodically export the template data so the NetFlow collector will understand what data is to be sent and also export the data flow set for the template. The key advantage to Flexible NetFlow is that the user configures a flow record, which is effectively converted to a Version 9 template and then forwarded to the collector. The figure below is a detailed example of the NetFlow Version 9 export format, including the header, template flow, and data flow sets.


Note

The NetFlow Version 5 export format is a fixed export format that would provide limited information for Flexible NetFlow data. This is why Flexible NetFlow uses the Version 9 export format.

Figure 3. Detailed Example of the NetFlow Version 9 Export Format

For more information on the Version 9 export format, refer to the white paper titled Cisco IOS NetFlow Version 9 Flow-Record Format, available at this URL: http:/​/​www.cisco.com/​en/​US/​tech/​tk648/​tk362/​technologies_​white_​paper09186a00800a3db9.shtml.

Flow Monitors

Flow monitors are the Flexible NetFlow component that is applied to interfaces to perform network traffic monitoring.

Flow monitors consist of a user-defined record, an optional flow exporter, and a cache that is automatically created at the time the flow monitor is applied to the first interface.

Flow monitors consist of a user-defined or predefined record, an optional flow exporter, and a cache that is automatically created at the time the flow monitor is applied to the first interface.

Flow data is collected from the network traffic and added to the flow monitor cache during the monitoring process based on the key and nonkey fields in the flow record.

Flexible NetFlow can be used to perform different types of analysis on the same traffic. In the figure below, packet 1 is analyzed using a record designed for standard traffic analysis on the input interface and a record designed for security analysis on the output interface.

Figure 4. Example of Using Two Flow Monitors to Analyze the Same Traffic



The figure below shows a more complex example of how you can apply different types of flow monitors with custom records.

Figure 5. Complex Example of Using Multiple Types of Flow Monitors with Custom Records



Normal

The default cache type is “normal”. In this mode, the entries in the cache are aged out according to the timeout active and timeout inactive settings. When a cache entry is aged out, it is removed from the cache and exported via any exporters configured.

Flow Samplers

Flow samplers are created as separate components in a router’s configuration. Flow samplers are used to reduce the load on the device that is running Flexible NetFlow by limiting the number of packets that are selected for analysis.

Samplers use random sampling techniques (modes); that is, a randomly selected sampling position is used each time a sample is taken.

Flow sampling exchanges monitoring accuracy for router performance. When you apply a sampler to a flow monitor, the overhead load on the router of running the flow monitor is reduced because the number of packets that the flow monitor must analyze is reduced. The reduction in the number of packets that are analyzed by the flow monitor causes a corresponding reduction in the accuracy of the information stored in the flow monitor’s cache.

Samplers are combined with flow monitors when they are applied to an interface with the ip flow monitor command.

Supported Flexible NetFlow Fields

The following tables provide a consolidated list of supported fields in Flexible NetFlow (FNF) for various traffic types and traffic direction.

Note

If the packet has a VLAN field, then that length is not accounted for.

Field

Layer 2 In

Layer 2 Out

IPv4 In

IP v4 Out

IPv6 In

IPv6 Out

Notes

Key or Collect Fields

Interface input

Yes

—

Yes

—

Yes

—

If you apply a flow monitor in the input direction:

  • Use the match keyword and use the input interface as a key field.

  • Use the collect keyword and use the output interface as a collect field. This field will be present in the exported records but with a value of 0.

Interface output

—

Yes

—

Yes

—

Yes

If you apply a flow monitor in the output direction:

  • Use the match keyword and use the output interface as a key field.

  • Use the collect keyword and use the input interface as a collect field. This field will be present in the exported records but with a value of 0.

Field

Layer 2 In

Layer 2 Out

IPv4 In

IP v4 Out

IPv6 In

IPv6 Out

Notes

Key Fields

Flow direction

Yes

Yes

Yes

Yes

Yes

Yes

Ethertype

Yes

Yes

—

—

—

—

VLAN input

Yes

—

Yes

—

Yes

—

Supported only for a switch port.

VLAN output

—

Yes

—

Yes

—

Yes

Supported only for a switch port.

dot1q VLAN input

Yes

—

Yes

—

Yes

—

Supported only for a switch port.

dot1q VLAN output

—

Yes

—

Yes

—

Yes

Supported only for a switch port.

dot1q priority

Yes

Yes

Yes

Yes

Yes

Yes

Supported only for a switch port.

MAC source address input

Yes

Yes

Yes

Yes

Yes

Yes

MAC source address output

—

—

—

—

—

—

MAC destination address input

Yes

—

Yes

—

Yes

—

MAC destination address output

—

Yes

—

Yes

—

Yes

IPv4 version

—

—

Yes

Yes

Yes

Yes

IPv4 TOS

—

—

Yes

Yes

Yes

Yes

IPv4 protocol

—

—

Yes

Yes

Yes

Yes

Must use if any of src/dest port, ICMP code/type, IGMP type or TCP flags are used.

IPv4 TTL

—

—

Yes

Yes

Yes

Yes

 

IPv4 source address

—

—

Yes

Yes

—

—

IPv4 destination address

—

—

Yes

Yes

—

—

ICMP IPv4 type

—

—

Yes

Yes

—

—

ICMP IPv4 code

—

—

Yes

Yes

—

—

IGMP type

—

—

Yes

Yes

—

—

Field

Layer 2 In

Layer 2 Out

IPv4 In

IP v4 Out

IPv6 In

IPv6 Out

Notes

Key Fields continued

IPv6 version

—

—

Yes

Yes

Yes

Yes

Same as IP version.

IPv6 protocol

—

—

Yes

Yes

Yes

Yes

Same as IP protocol. Must use if any of src/dest port, ICMP code/type, IGMP type or TCP flags are used.

IPv6 source address

—

—

—

—

Yes

Yes

IPv6 destination address

—

—

—

—

Yes

Yes

IPv6 traffic-class

—

—

Yes

Yes

Yes

Yes

Same as IP TOS.

IPv6 hop-limit

—

—

Yes

Yes

Yes

Yes

Same as IP TTL.

ICMP IPv6 type

—

—

—

—

Yes

Yes

ICMP IPv6 code

—

—

—

—

Yes

Yes

source-port

—

—

Yes

Yes

Yes

Yes

dest-port

—

—

Yes

Yes

Yes

Yes

Field

Layer 2 In

Layer 2 Out

IPv4 In

IP v4 Out

IPv6 In

IPv6 Out

Notes

Collect Fields

Bytes long

Yes

Yes

Yes

Yes

Yes

Yes

Packet size = (Ethernet frame size including FCS - 18 bytes)

Recommended:

Avoid this field and use Bytes layer2 long.

Packets long

Yes

Yes

Yes

Yes

Yes

Yes

Timestamp absolute first

Yes

Yes

Yes

Yes

Yes

Yes

Timestamp absolute last

Yes

Yes

Yes

Yes

Yes

Yes

TCP flags

Yes

Yes

Yes

Yes

Yes

Yes

Collects all flags.

Bytes layer2 long

Yes

Yes

Yes

Yes

Yes

Yes

Default Settings

The following table lists the Flexible NetFlow default settings for the switch.

Table 3 Default Flexible NetFlow Settings

Setting

Default

Flow active timeout

1800 seconds

Flow timeout inactive

15 seconds

How to Configure Flexible NetFlow

To configure Flexible NetFlow, follow these general steps:

  1. Create a flow record by specifying keys and non-key fields to the flow.

  2. Create an optional flow exporter by specifying the protocol and transport destination port, destination, and other parameters.

  3. Create a flow monitor based on the flow record and flow exporter.

  4. Create an optional sampler.

  5. Apply the flow monitor to a Layer 2 port, Layer 3 port, or VLAN.

  6. If applicable to your configuration, configure a WLAN to apply a flow monitor to.

Configuring a 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.    match flow cts {source | destination} group-tag

    8.    collect interface {input | output}

    9.    Repeat the above step as required to configure additional nonkey fields for the record.

    10.    end

    11.    show flow record record-name

    12.    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
     
    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 match flow cts {source | destination} group-tag


    Example: 
    Device(config-flow-record)# match flow cts source group-tag

Device(config-flow-record)# match flow cts destination group-tag
     
    Note   

    This example configures the CTS source group tag and destination group tag 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 .

    Note   
    • Ingress:

      • In an incoming packet, if a header is present, SGT will reflect the same value as the header. If no value is present, it will show zero.

      • The DGT value will not depend on the ingress port SGACL configuration.

    • Egress:

      • If either propagate SGT or CTS is disabled on the egress interface, then SGT will be zero.

      • In an outgoing packet, if SGACL configuration that corresponds to the (SGT, DGT) exists, DGT will be non-zero.

      • If SGACL is disabled on the egress port/VLAN or if global SGACL enforcement is disabled, then DGT will be zero

     
    Step 8 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 9 Repeat the above step as required to configure additional nonkey fields for the record.  

    —

     
    Step 10 end


    Example: 
    Device(config-flow-record)# end
     

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

     
    Step 11 show flow record record-name


    Example: 
    Device# show flow record FLOW_RECORD-1
     

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

     
    Step 12 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 Flow Exporter

    You can create a flow export to define the export parameters for a flow.


    Note

    Each flow exporter supports only one destination. If you want to export the data to multiple destinations, you must configure multiple flow exporters and assign them to the flow monitor.

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

    SUMMARY STEPS

      1.    configure terminal

      2.    flow exporter name

      3.    description string

      4.    destination {ipv4-address|ipv6-address}

      5.    dscp value

      6.    source { source type }

      7.    transport udp number

      8.    ttl seconds

      9.    export-protocol {netflow-v9 | ipfix}

      10.    end

      11.    show flow exporter [name record-name]

      12.    copy running-config startup-config


    DETAILED STEPS
       Command or ActionPurpose
      Step 1configure terminal


      Example: 
      
Switch# configure terminal
       

      Enters the global configuration mode.

       
      Step 2flow exporter name


      Example: 
      Switch(config)# flow exporter ExportTest
       

      Creates a flow exporter and enters flow exporter configuration mode. You can also use this command to modify an existing flow exporter.

       

      Step 3description string


      Example: 
      Switch(config-flow-exporter)# description ExportV9
       

      (Optional) Describes this flow record as a maximum 63-character string.

       

      Step 4destination {ipv4-address|ipv6-address}


      Example: 
      Switch(config-flow-exporter)# destination 192.0.2.1 (IPv4 destination)

Switch(config-flow-exporter)# destination 2001:0:0:24::10 (IPv6 destination)
       

      Sets the IPv4/IPv6 destination address or hostname for this exporter.

       

      Step 5 dscp value


      Example: 
      Switch(config-flow-exporter)# dscp 0
       

      (Optional) Specifies the differentiated services codepoint value. The range is from 0 to 63. The default is 0.

       

      Step 6source { source type }


      Example: 
      Switch(config-flow-exporter)# source gigabitEthernet1/0/1
       

      (Optional) Specifies the interface to use to reach the NetFlow collector at the configured destination. The following interfaces can be configured as source:

      • Auto Template—Auto-Template interface

      • Capwap—CAPWAP tunnel interface

      • GigabitEthernet—Gigabit Ethernet IEEE 802

      • GroupVI—Group virtual interface

      • Internal Interface—Internal interface

      • Loopback—Loopback interface

      • Null—Null interface

      • Port-channel—Ethernet Channel of interface

      • TenGigabitEthernet—10-Gigabit Ethernet

      • Tunnel—Tunnel interface

      • Vlan—Catalyst VLANs

       

      Step 7transport udp number


      Example: 
      Switch(config-flow-exporter)# transport udp 200
       

      (Optional) Specifies the UDP port to use to reach the NetFlow collector. The range is from 0 to 65535. For IPFIX exporting protocol, the default destination port is 4739.

       
      Step 8ttl seconds


      Example: 
      Switch(config-flow-exporter)# ttl 210
       

      (Optional) Configures the time-to-live (TTL) value for datagrams sent by the exporter. The range is from 1 to 255 seconds. The default is 255.

       
      Step 9 export-protocol {netflow-v9 | ipfix}


      Example: 
      Switch(config-flow-exporter)# export-protocol netflow-v9
       

      Specifies the version of the NetFlow export protocol used by the exporter.

      • Default: netflow-v9.

       
      Step 10end


      Example: 
      
Switch(config-flow-record)#  end
       

      Returns to privileged EXEC mode.

       
      Step 11show flow exporter [name record-name]


      Example: 
      Switch show flow exporter ExportTest
       

      (Optional) Displays information about NetFlow flow exporters.

       

      Step 12copy running-config startup-config


      Example: 
      
Switch# copy running-config 
startup-config
       

      (Optional) Saves your entries in the configuration file.

       
      What to Do Next

      Define a flow monitor based on the flow record and flow exporter.

      Related Concepts
      Exporters
      Related References
      Example: Configuring a Flow
      Example: Monitoring IPv4 ingress traffic
      Example: Monitoring IPv4 egress traffic

      Creating a 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, 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 {timeout {active | inactive} seconds | type { normal }

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

        8.    exporter exporter-name

        9.    end

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

        11.    show running-config flow monitor monitor-name

        12.    copy running-config startup-config


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 enable


        Example: 
        Switch> enable
         

        Enables privileged EXEC mode.

        • Enter your password if prompted.

         
        Step 2 configure terminal


        Example: 
        Switch# configure terminal
         

        Enters global configuration mode.

         
        Step 3 flow monitor monitor-name


        Example: 
        Switch(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: 
        Switch(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: 
        Switch(config-flow-monitor)# record FLOW-RECORD-1
         

        Specifies the record for the flow monitor.

         
        Step 6 cache {timeout {active | inactive} seconds | type { normal }


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

        Associates a flow cache with the specified flow monitor.

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

        —

         
        Step 8 exporter exporter-name


        Example: 
        Switch(config-flow-monitor)# exporter EXPORTER-1
         

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

         
        Step 9 end


        Example: 
        Switch(config-flow-monitor)# end
         

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

         
        Step 10 show flow monitor [[name] monitor-name [cache [format {csv | record | table}]] ]


        Example: 
        Switch# show flow monitor FLOW-MONITOR-2 cache
         

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

        Note    To sort by CTS flow source or destination tags, enter the show flow monitor monitor-name cache sort flow cts {source | destination} group-tag format {csv | record | table} command.
         
        Step 11 show running-config flow monitor monitor-name


        Example: 
        Switch# show running-config flow monitor FLOW_MONITOR-1
         

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

         
        Step 12copy running-config startup-config


        Example: 
        
Switch# copy running-config 
startup-config
         

        (Optional) Saves your entries in the configuration file.

         

        Creating a Flow Sampler

        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 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 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 0 to 1024.

           
          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.

           

          Applying a Flow to an Interface

          You can apply a flow monitor and an optional sampler to an interface.

          SUMMARY STEPS

            1.    configure terminal

            2.    interface type

            3.    {ip flow monitor | ipv6 flow monitor}name [|sampler name] { input}

            4.    end

            5.    show flow interface [interface-type number]

            6.    copy running-config startup-config


          DETAILED STEPS
             Command or ActionPurpose
            Step 1configure terminal


            Example: 
            
Switch# configure terminal
             

            Enters the global configuration mode.

             
            Step 2interface type


            Example: 
            Switch(config)# interface GigabitEthernet1/0/1
             

            Enters interface configuration mode and configures an interface.

            Command parameters for the interface configuration include:

            • GigabitEthernet—GigabitEthernet IEEE 802

            • Loopback—Loopback interface

            • TenGigabitEthernet—10- Gigabit Ethernet

            • Vlan—Catalyst VLANs

            • Range—Interface range

            • WLAN—WLAN interface

             

            Step 3{ip flow monitor | ipv6 flow monitor}name [|sampler name] { input}


            Example: 
            Switch(config-if)# ip flow monitor MonitorTest input
             

            Associate an IPv4 or an IPv6 flow monitor, and an optional sampler to the interface for input or output packets.

             

            Step 4end


            Example: 
            
Switch(config-flow-monitor)#  end
             

            Returns to privileged EXEC mode.

             
            Step 5show flow interface [interface-type number]


            Example: 
            Switch# show flow interface
             

            (Optional) Displays information about NetFlow on an interface.

             

            Step 6copy running-config startup-config


            Example: 
            
Switch# copy running-config 
startup-config
             

            (Optional) Saves your entries in the configuration file.

             

            Configuring a Bridged NetFlow on a VLAN

            You can apply a flow monitor and an optional sampler to a VLAN.

            SUMMARY STEPS

              1.    configure terminal

              2.    vlan [configuration] vlan-id

              3.    ip flow monitor monitor name [sampler sampler name] {input |output}

              4.    copy running-config startup-config


            DETAILED STEPS
               Command or ActionPurpose
              Step 1configure terminal


              Example: 
              
Switch# configure terminal
               

              Enters the global configuration mode.

               
              Step 2vlan [configuration] vlan-id


              Example: 
              Switch(config)# vlan configuration 30
Switch(config-vlan-config)#
               

              Enters VLAN or VLAN configuration mode.

               

              Step 3ip flow monitor monitor name [sampler sampler name] {input |output}


              Example: 
              Switch(config-vlan-config)# ip flow monitor MonitorTest input
               

              Associates a flow monitor and an optional sampler to the VLAN for input or output packets.

               

              Step 4copy running-config startup-config


              Example: 
              
Switch# copy running-config 
startup-config
               

              (Optional) Saves your entries in the configuration file.

               

              Configuring Layer 2 NetFlow

              You can define Layer 2 keys in Flexible NetFlow records that you can use to capture flows in Layer 2 interfaces.

              SUMMARY STEPS

                1.    configure terminal

                2.    flow record name

                3.    match datalink {dot1q |ethertype | mac | vlan}

                4.    end

                5.    show flow record [name ]

                6.    copy running-config startup-config


              DETAILED STEPS
                 Command or ActionPurpose
                Step 1configure terminal


                Example: 
                
Switch# configure terminal
                 

                Enters the global configuration mode.

                 
                Step 2flow record name


                Example:
                Switch(config)# flow record L2_record
Switch(config-flow-record)#
                                  		Enters flow record configuration mode.

                 

                Step 3match datalink {dot1q |ethertype | mac | vlan}


                Example:
                Switch(config-flow-record)# match datalink ethertype
                 

                Specifies the Layer 2 attribute as a key.

                 

                Step 4end


                Example:
                
Switch(config-flow-record)#  end
                 

                Returns to privileged EXEC mode.

                 

                Step 5show flow record [name ]


                Example:
                Switch# show flow record
                 

                (Optional) Displays information about NetFlow on an interface.

                 

                Step 6copy running-config startup-config


                Example:
                
Switch# copy running-config 
startup-config
                 

                (Optional) Saves your entries in the configuration file.

                 

                Configuring WLAN to Apply Flow Monitor in Data Link Input/Output Direction

                SUMMARY STEPS

                  1.    configure terminal

                  2.    wlan [wlan-name { wlan-id SSID_NetworkName | wlan_id} | wlan-name | shutdown}

                  3.    datalink flow monitor monitor-name {input | output}

                  4.    end

                  5.    show run wlan wlan-name


                DETAILED STEPS
                   Command or ActionPurpose
                  Step 1 configure terminal


                  Example: 
                  Switch# configure terminal
                   

                  Enters global configuration mode.

                   

                  Step 2 wlan [wlan-name { wlan-id SSID_NetworkName | wlan_id} | wlan-name | shutdown}


                  Example: 
                  Switch (config) # wlan wlan1
                   

                  Enters WLAN configuration submode.

                  wlan-id is the wireless LAN identifier. The range is 1 to 64.

                  SSID_NetworkName is the SSID which can contain 32 alphanumeric characters.

                  Note    If you have already configured this command, enter the wlan wlan-name command.

                   
                  Step 3 datalink flow monitor monitor-name {input | output}


                  Example: 
                  Switch (config-wlan) # datalink flow monitor flow-monitor-1 {input | output}
                   

                  Applies flow monitor to Layer 2 traffic in the direction of interest.

                   

                  Step 4 end


                  Example: 
                  Switch (config) # end
                   

                  Returns to privileged EXEC mode.

                   

                  Step 5 show run wlan wlan-name


                  Example: 
                  Switch # show wlan mywlan
                   

                  (Optional) Verifies your configuration.

                   

                  Configuring WLAN to Apply Flow Monitor in IPV4 and IPv6 Input/Output Direction

                  SUMMARY STEPS

                    1.    configure terminal

                    2.    wlan {wlan-name { wlan-id SSID_NetworkName | wlan_id} | wlan-name | shutdown}

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

                    4.    end

                    5.    show run wlan wlan-name


                  DETAILED STEPS
                     Command or ActionPurpose
                    Step 1 configure terminal


                    Example: 
                    Switch# configure terminal
                     

                    Enters global configuration mode

                     

                    Step 2 wlan {wlan-name { wlan-id SSID_NetworkName | wlan_id} | wlan-name | shutdown}


                    Example: 
                    Switch (config) # wlan wlan1
                     

                    Enters WLAN configuration submode.

                    wlan-id is the wireless LAN identifier. The range is 1 to 64.

                    SSID_NetworkName is the SSID which can contain 32 alphanumeric characters.

                    Note    If you have already configured this command, enter the wlan wlan-name command.

                     

                    Step 3{ip | ipv6} flow monitor monitor-name {input | output}


                    Example: 
                    Switch (config-wlan) # ip flow monitor flow-monitor-1 input
                     

                    Associates a flow monitor to the WLAN for input or output packets.

                     

                    Step 4 end


                    Example: 
                    Switch (config) # end
                     

                    Returns to privileged EXEC mode.

                     

                    Step 5 show run wlan wlan-name


                    Example: 
                    Switch # show wlan mywlan
                     

                    (Optional) Verifies your configuration.

                     

                    Related Concepts
                    Wireless Flexible NetFlow Overview
                    Related References
                    Example: Configuring IPv4 Flexible NetFlow in WLAN (Ingress Direction)
                    Example: Configuring IPv6 and Transport Flag Flexible NetFlow in WLAN (Egress Direction)
                    Example: Configuring IPv6 Flexible NetFlow in WLAN (Both Ingress and Egress Directions)

                    Monitoring Flexible NetFlow

                    The commands in the following table can be used to monitor Flexible NetFlow.

                    Table 4 Flexible NetFlow Monitoring Commands

                    Command

                    Purpose

                    show flow exporter [broker | export-ids | name | name | statistics | templates]

                    Displays information about NetFlow flow exporters and statistics.

                    show flow exporter [ name exporter-name]

                    Displays information about NetFlow flow exporters and statistics.

                    show flow interface

                    Displays information about NetFlow interfaces.

                    show flow monitor [ name exporter-name]

                    Displays information about NetFlow flow monitors and statistics.

                    show flow monitor statistics

                    Displays the statistics for the flow monitor

                    show flow monitor cache format {table | record | csv}

                    Displays the contents of the cache for the flow monitor, in the format specified.

                    show flow record [ name record-name]

                    Displays information about NetFlow flow records.

                    show flow ssid

                    Displays NetFlow monitor installation status for a WLAN.

                    show sampler [broker | name | name]

                    Displays information about NetFlow samplers.

                    show wlan wlan-name

                    Displays the WLAN configured on the device.

                    Configuration Examples for Flexible NetFlow

                    Example: Configuring a Flow

                    This example shows how to create a flow and apply it to an interface: 

                    
Switch# configure terminal 
Enter configuration commands, one per line. End with CNTL/Z.

Switch(config)# flow export export1
Switch(config-flow-exporter)# destination 10.0.101.254
Switch(config-flow-exporter)# transport udp 2055
Switch(config-flow-exporter)# exit
Switch(config)# flow record record1
Switch(config-flow-record)# match ipv4 source address
Switch(config-flow-record)# match ipv4 destination address
Switch(config-flow-record)# match ipv4 protocol
Switch(config-flow-record)# match transport source-port 
Switch(config-flow-record)# match transport destination-port
 
Switch(config-flow-record)# collect counter byte long
Switch(config-flow-record)# collect counter packet long
Switch(config-flow-record)# collect timestamp absolute first
Switch(config-flow-record)# collect timestamp absolute last 
Switch(config-flow-record)# exit
Switch(config)# flow monitor monitor1
Switch(config-flow-monitor)# record record1
Switch(config-flow-monitor)# exporter export1
Switch(config-flow-monitor)# exit
Switch(config)# interface tenGigabitEthernet 1/0/1
Switch(config-if)# ip flow monitor monitor1 input
Switch(config-if)# end
                    Related Concepts
                    Exporters
                    Monitors
                    Related Tasks
                    Creating a Flow Exporter
                    Creating a Flow Monitor

                    Example: Monitoring IPv4 ingress traffic

                    This example shows how to monitor IPv4 ingress traffic (int g1/0/11 sends traffic to int g1/0/36 and int g3/0/11). 

                    
Switch# configure terminal 
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# flow record  fr-1
Switch(config-flow-record)# match ipv4 source address
Switch(config-flow-record)# match ipv4 destination address
Switch(config-flow-record)# match interface input
Switch(config-flow-record)# collect counter bytes long
Switch(config-flow-record)# collect counter packets long
Switch(config-flow-record)# collect timestamp absolute first
Switch(config-flow-record)# collect timestamp absolute last 
Switch(config-flow-record)# collect counter bytes layer2 long
Switch(config-flow-record)# exit

Switch(config)# flow exporter fe-ipfix6
Switch(config-flow-exporter)# destination 2001:0:0:24::10
Switch(config-flow-exporter)# source Vlan106
Switch(config-flow-exporter)# transport udp 4739
Switch(config-flow-exporter)# export-protocol ipfix
Switch(config-flow-exporter)# template data timeout 240
Switch(config-flow-exporter)# exit

Switch(config)# flow exporter fe-ipfix
Switch(config-flow-exporter)# description IPFIX format collector 100.0.0.80
Switch(config-flow-exporter)# destination 100.0.0.80
Switch(config-flow-exporter)# dscp 30
Switch(config-flow-exporter)# ttl 210
Switch(config-flow-exporter)# transport udp 4739
Switch(config-flow-exporter)# export-protocol ipfix
Switch(config-flow-exporter)# template data timeout 240
Switch(config-flow-exporter)# exit

Switch(config)# flow exporter fe-1
Switch(config-flow-exporter)# destination 10.5.120.16
Switch(config-flow-exporter)# source Vlan105
Switch(config-flow-exporter)# dscp 32
Switch(config-flow-exporter)# ttl 200
Switch(config-flow-exporter)# transport udp 2055

Switch(config-flow-exporter)# template data timeout 240
Switch(config-flow-exporter)# exit

Switch(config)# flow monitor fm-1
Switch(config-flow-monitor)# exporter fe-ipfix6
Switch(config-flow-monitor)# exporter fe-ipfix
Switch(config-flow-monitor)# exporter fe-1
Switch(config-flow-monitor)# cache timeout inactive 60
Switch(config-flow-monitor)#  cache timeout active 180
Switch(config-flow-monitor)# record fr-1
Switch(config-flow-monitor)# end

Switch# show running-config interface g1/0/11
Switch# show running-config interface g1/0/36
Switch# show running-config interface g3/0/11
Switch# show flow monitor fm-1 cache format table
                    Related Concepts
                    Exporters
                    Monitors
                    Related Tasks
                    Creating a Flow Exporter
                    Creating a Flow Monitor

                    Example: Monitoring IPv4 egress traffic

                    
Switch# configure terminal 
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# flow record  fr-1 out
Switch(config-flow-record)# match ipv4 source address
Switch(config-flow-record)# match ipv4 destination address
Switch(config-flow-record)# match interface output
Switch(config-flow-record)# collect counter bytes long
Switch(config-flow-record)# collect counter packets long
Switch(config-flow-record)# collect timestamp absolute first
Switch(config-flow-record)# collect timestamp absolute last 
Switch(config-flow-record)# exit

Switch(config)# flow exporter fe-1
Switch(config-flow-exporter)# destination 10.5.120.16
Switch(config-flow-exporter)# source Vlan105
Switch(config-flow-exporter)# dscp 32
Switch(config-flow-exporter)# ttl 200
Switch(config-flow-exporter)# transport udp 2055
Switch(config-flow-exporter)# template data timeout 240
Switch(config-flow-exporter)# exit

Switch(config)# flow exporter fe-ipfix6
Switch(config-flow-exporter)# destination 2001:0:0:24::10
Switch(config-flow-exporter)# source Vlan106
Switch(config-flow-exporter)# transport udp 4739
Switch(config-flow-exporter)# export-protocol ipfix
Switch(config-flow-exporter)# template data timeout 240
Switch(config-flow-exporter)# exit

Switch(config)# flow exporter fe-ipfix
Switch(config-flow-exporter)# description IPFIX format collector 100.0.0.80
Switch(config-flow-exporter)# destination 100.0.0.80
Switch(config-flow-exporter)# dscp 30
Switch(config-flow-exporter)# ttl 210
Switch(config-flow-exporter)# transport udp 4739
Switch(config-flow-exporter)# export-protocol ipfix
Switch(config-flow-exporter)# template data timeout 240
Switch(config-flow-exporter)# exit

Switch(config)# flow monitor fm-1-output
Switch(config-flow-monitor)# exporter fe-1
Switch(config-flow-monitor)# exporter fe-ipfix6
Switch(config-flow-monitor)# exporter fe-ipfix
Switch(config-flow-monitor)# cache timeout inactive 50
Switch(config-flow-monitor)#  cache timeout active 120
Switch(config-flow-monitor)# record fr-1-out
Switch(config-flow-monitor)# end

Switch# show flow monitor fm-1-output cache format table
                    Related Concepts
                    Exporters
                    Monitors
                    Related Tasks
                    Creating a Flow Exporter
                    Creating a Flow Monitor

                    Example: Configuring IPv4 Flexible NetFlow in WLAN (Ingress Direction)

                    The following example shows how to configure IPv4 Flexible NetFlow on WLAN ingress direction: 

                    
Switch# configure terminal
Switch(config)# flow record fr_v4
Switch(config-flow-record)#	match ipv4 destination address
Switch(config-flow-record)#	match ipv4 source address
Switch(config-flow-record)#	match ipv4 protocol
Switch(config-flow-record)#	match ipv4 tos
Switch(config-flow-record)#	match ipv4 ttl
Switch(config-flow-record)#	match ipv4 version
Switch(config-flow-record)#	match wireless ssid
Switch(config-flow-record)#	collect wireless ap mac address
Switch(config-flow-record)#	collect counter packets long
Switch(config-flow-record)#	collect counter bytes long
Switch(config-flow-record)#	collect timestamp absolute first
Switch(config-flow-record)#	collect timestamp absolute last
Switch(config-flow-record)# exit

Switch(config)# flow monitor fm_v4
Switch(config-flow-monitor)#	record fr_v4
Switch(config-flow-record)# exit

Switch(config)#	wlan wlan_1
Switch(config-wlan)#	ip flow monitor fm_v4 in
Switch(config-wlan)# end

Switch# show flow monitor fm_v4 cache
                    Related Concepts
                    Wireless Flexible NetFlow Overview
                    Related Tasks
                    Configuring WLAN to Apply Flow Monitor in IPV4 and IPv6 Input/Output Direction

                    Example: Configuring IPv6 and Transport Flag Flexible NetFlow in WLAN (Egress Direction)

                    The following example shows how to configure IPv6 and transport flag Flexible NetFlow on WLAN egress direction: 

                    
Switch# configure terminal
Switch(config)#	flow record fr_v6
Switch(config-flow-record)# match ipv6 destination address
Switch(config-flow-record)#	match ipv6 source address
Switch(config-flow-record)#	match ipv6 hop-limit
Switch(config-flow-record)#	match ipv6 protocol
Switch(config-flow-record)#	match ipv6 traffic
Switch(config-flow-record)#	match ipv6 version
Switch(config-flow-record)#	match wireless ssid
Switch(config-flow-record)#	collect wireless ap mac address
Switch(config-flow-record)#	collect counter bytes long
Switch(config-flow-record)#	collect transport tcp flags
Switch(config-flow-record)# exit

Switch(config)#	flow monitor fm_v6
Switch(config-flow-monitor)#	record fr_v6
Switch(config-flow-monitor)# exit

Switch(config)#	wlan wlan_1
Switch(config-wlan)#	ipv6 flow monitor fm_v6 out
Switch(config-wlan)# end

Switch# show flow monitor fm_v6 cache

                    Note

                    On the switch, you cannot specify which TCP flag to collect. You can only specify to collect transport TCP flags.

                    Related Concepts
                    Wireless Flexible NetFlow Overview
                    Related Tasks
                    Configuring WLAN to Apply Flow Monitor in IPV4 and IPv6 Input/Output Direction

                    Example: Configuring IPv6 Flexible NetFlow in WLAN (Both Ingress and Egress Directions)

                    The following example shows how to configure IPv6 Flexible NetFlow on WLAN in both directions: 

                    
Switch# configure terminal
Switch (config)# flow record fr_v6
Switch (config-flow-record)# match ipv6 destination address
Switch (config-flow-record)# match ipv6 source address
Switch (config-flow-record)# match ipv6 hop-limit
Switch (config-flow-record)# match ipv6 protocol
Switch (config-flow-record)# match ipv6 traffic
Switch (config-flow-record)# match ipv6 version
Switch (config-flow-record)#	match wireless ssid
Switch (config-flow-record)#	collect wireless ap mac address
Switch (config-flow-record)# collect counter packets long
Switch (config-flow-record)# exit

Switch (config)# flow monitor fm_v6
Switch (config-flow-monitor)# record fr_v6
Switch (config-flow-monitor)# exit

Switch (config)# wlan wlan_1
Switch (config-wlan)# ipv6 flow monitor fm_v6 in
Switch (config-wlan)# ipv6 flow monitor fm_v6 out
Switch (config-wlan)# end

Switch# show flow monitor fm_v6 cache
                    Related Concepts
                    Wireless Flexible NetFlow Overview
                    Related Tasks
                    Configuring WLAN to Apply Flow Monitor in IPV4 and IPv6 Input/Output Direction

                    Example: Monitoring wireless ingress traffic

                    
Switch# configure terminal 
Enter configuration commands, one per line. End with CNTL/Z.
Switch(config)# flow record fr-wlan-input
Switch(config-flow-record)# match datalink mac source address input
Switch(config-flow-record)# match datalink mac destination address input
Switch(config-flow-record)# match ipv4 source address
Switch(config-flow-record)# match ipv4 destination address
Switch(config-flow-record)# match wireless ssid
Switch(config-flow-record)# collect counter bytes long
Switch(config-flow-record)# collect counter packets long
Switch(config-flow-record)# collect timestamp absolute first
Switch(config-flow-record)# collect timestamp absolute last 
Switch(config-flow-record)# exit

Switch(config)# flow exporter fe-ipfix
Switch(config-flow-exporter)# description IPFIX format collector 100.0.0.80
Switch(config-flow-exporter)# destination 100.0.0.80
Switch(config-flow-exporter)# dscp 30
Switch(config-flow-exporter)# ttl 210
Switch(config-flow-exporter)# transport udp 4739
Switch(config-flow-exporter)# export-protocol ipfix
Switch(config-flow-exporter)# template data timeout 240
Switch(config-flow-exporter)# exit

Switch(config)# flow exporter fe-ipfix6
Switch(config-flow-exporter)# destination 2001:0:0:24::10
Switch(config-flow-exporter)# source Vlan106
Switch(config-flow-exporter)# transport udp 4739
Switch(config-flow-exporter)# export-protocol ipfix
Switch(config-flow-exporter)# template data timeout 240
Switch(config-flow-exporter)# exit

Switch(config)# flow monitor fm-wlan-input
Switch(config-flow-monitor)# exporter fe-ipfix
Switch(config-flow-monitor)# exporter fe-ipfix6
Switch(config-flow-monitor)# cache timeout inactive 30
Switch(config-flow-monitor)#  cache timeout active 180
Switch(config-flow-monitor)# record fr-wlan-input
Switch(config-flow-monitor)# end

Switch# show running-config wlan nfl_1
Switch# show flow monitor fm-wlan-input cache format table

                    Additional References

                    Related Documents

                    Related Topic Document Title

                    Flexible NetFlow CLI Commands

                    Cisco Flexible NetFlow Command Reference (Catalyst 3850 Switches)

                    Flexible NetFlow Command Reference, Cisco IOS XE Release 3SE (Cisco WLC 5700 Series)

                    Error Message Decoder

                    Description Link

                    To help you research and resolve system error messages in this release, use the Error Message Decoder tool.

                    https:/​/​www.cisco.com/​cgi-bin/​Support/​Errordecoder/​index.cgi

                    Standards and RFCs

                    Standard/RFC Title

                    RFC 3954

                    Cisco Systems NetFlow Services Export Version 9

                    MIBs

                    MIB MIBs Link

                    All supported MIBs for this release.

                    To locate and download MIBs for selected platforms, Cisco IOS 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 website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

                    To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

                    Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

                    http:/​/​www.cisco.com/​support

                    Feature Information for Flexible NetFlow

                    Release

                    Modification

                    Cisco IOS XE 3.2SE

                    This feature was introduced.

                    Cisco IOS XE 3.3SE

                    The following new commands were added:

                    • match wireless ssid

                    • collect wireless ap mac address