Cisco Flexible NetFlow Configuration Guide, Cisco IOS XE Release Americas Headquarters

Cisco Flexible NetFlow Configuration Guide, Cisco IOS XE Release Americas Headquarters
Cisco Flexible NetFlow Configuration Guide, Cisco IOS XE Release
3SE (Catalyst 3850 Switches)
First Published: January 29, 2013
Last Modified: November 07, 2014
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Text Part Number: OL-28354-02
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CONTENTS
Preface
Preface vii
Document Conventions vii
Related Documentation ix
Obtaining Documentation and Submitting a Service Request ix
CHAPTER 1
Using the Command-Line Interface 1
Information About Using the Command-Line Interface 1
Command Modes 1
Understanding Abbreviated Commands 3
No and Default Forms of Commands 3
CLI Error Messages 4
Configuration Logging 4
Using the Help System 4
How to Use the CLI to Configure Features 6
Configuring the Command History 6
Changing the Command History Buffer Size 6
Recalling Commands 6
Disabling the Command History Feature 7
Enabling and Disabling Editing Features 7
Editing Commands Through Keystrokes 8
Editing Command Lines That Wrap 9
Searching and Filtering Output of show and more Commands 10
Accessing the CLI on a Switch Stack 11
Accessing the CLI Through a Console Connection or Through Telnet 11
CHAPTER 2
Configuring Flexible NetFlow 13
Finding Feature Information 13
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Contents
Prerequisites 14
Prerequisites for Flexible NetFlow 14
Prerequisites for Wireless Flexible NetFlow 15
Restrictions 15
Restrictions for Flexible NetFlow 15
Restrictions for Wireless Flexible NetFlow 17
Information About NetFlow 18
Flexible NetFlow Overview 18
Wireless Flexible NetFlow Overview 18
Flow Records 19
Flexible NetFlow Match Parameters 20
Flexible NetFlow Collect Parameters 22
Exporters 23
Export Formats 23
Monitors 24
Samplers 24
Supported Flexible NetFlow Fields 24
Default Settings 29
How to Configure Flexible NetFlow 29
Creating a Flow Record 29
Creating a Flow Exporter 32
Creating a Flow Monitor 35
Creating a Sampler 36
Applying a Flow to an Interface 38
Configuring a Bridged NetFlow on a VLAN 39
Configuring Layer 2 NetFlow 40
Configuring WLAN to Apply Flow Monitor in Data Link Input/Output Direction 42
Configuring WLAN to Apply Flow Monitor in IPV4 and IPv6 Input/Output Direction 43
Monitoring Flexible NetFlow 44
Configuration Examples for Flexible NetFlow 45
Example: Configuring a Flow 45
Example: Configuring IPv4 Flexible NetFlow in WLAN (Ingress Direction) 45
Example: Configuring IPv6 and Transport Flag Flexible NetFlow in WLAN (Egress
Direction) 46
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Contents
Example: Configuring IPv6 Flexible NetFlow in WLAN (Both Ingress and Egress
Directions) 47
Additional References 47
Feature Information for Flexible NetFlow 49
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Contents
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Preface
• Document Conventions, page vii
• Related Documentation, page ix
• Obtaining Documentation and Submitting a Service Request, page ix
Document Conventions
This document uses the following conventions:
Convention
Description
^ or Ctrl
Both the ^ symbol and Ctrl represent the Control (Ctrl) key on a keyboard. For
example, the key combination ^D or Ctrl-D means that you hold down the Control
key while you press the D key. (Keys are indicated in capital letters but are not
case sensitive.)
bold font
Commands and keywords and user-entered text appear in bold font.
Italic font
Document titles, new or emphasized terms, and arguments for which you supply
values are in italic font.
Courier
font
Bold Courier
Terminal sessions and information the system displays appear in courier font.
font
Bold Courier
font indicates text that the user must enter.
[x]
Elements in square brackets are optional.
...
An ellipsis (three consecutive nonbolded periods without spaces) after a syntax
element indicates that the element can be repeated.
|
A vertical line, called a pipe, indicates a choice within a set of keywords or
arguments.
[x | y]
Optional alternative keywords are grouped in brackets and separated by vertical
bars.
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Preface
Document Conventions
Convention
Description
{x | y}
Required alternative keywords are grouped in braces and separated by vertical
bars.
[x {y | z}]
Nested set of square brackets or braces indicate optional or required choices
within optional or required elements. Braces and a vertical bar within square
brackets indicate a required choice within an optional element.
string
A nonquoted set of characters. Do not use quotation marks around the string or
the string will include the quotation marks.
<>
Nonprinting characters such as passwords are in angle brackets.
[]
Default responses to system prompts are in square brackets.
!, #
An exclamation point (!) or a pound sign (#) at the beginning of a line of code
indicates a comment line.
Reader Alert Conventions
This document may use the following conventions for reader alerts:
Note
Tip
Caution
Timesaver
Warning
Means reader take note. Notes contain helpful suggestions or references to material not covered in the
manual.
Means the following information will help you solve a problem.
Means reader be careful. In this situation, you might do something that could result in equipment damage
or loss of data.
Means the described action saves time. You can save time by performing the action described in the
paragraph.
IMPORTANT SAFETY INSTRUCTIONS
This warning symbol means danger. You are in a situation that could cause bodily injury. Before you
work on any equipment, be aware of the hazards involved with electrical circuitry and be familiar with
standard practices for preventing accidents. Use the statement number provided at the end of each warning
to locate its translation in the translated safety warnings that accompanied this device. Statement 1071
SAVE THESE INSTRUCTIONS
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Preface
Related Documentation
Related Documentation
Note
Before installing or upgrading the switch, refer to the switch release notes.
• Cisco Catalyst 3850 Switch documentation, located at:
http://www.cisco.com/go/cat3850_docs
• Cisco SFP, SFP+, and QSFP+ modules documentation, including compatibility matrixes, located at:
http://www.cisco.com/en/US/products/hw/modules/ps5455/tsd_products_support_series_home.html
• Cisco Validated Designs documents, located at:
http://www.cisco.com/go/designzone
• Error Message Decoder, located at:
https://www.cisco.com/cgi-bin/Support/Errordecoder/index.cgi
Obtaining Documentation and Submitting a Service Request
For information on obtaining documentation, submitting a service request, and gathering additional information,
see the monthly What's New in Cisco Product Documentation, which also lists all new and revised Cisco
technical documentation, at:
http://www.cisco.com/c/en/us/td/docs/general/whatsnew/whatsnew.html
Subscribe to the What's New in Cisco Product Documentation as a Really Simple Syndication (RSS) feed
and set content to be delivered directly to your desktop using a reader application. The RSS feeds are a free
service and Cisco currently supports RSS version 2.0.
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Preface
Obtaining Documentation and Submitting a Service Request
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CHAPTER
1
Using the Command-Line Interface
• Information About Using the Command-Line Interface, page 1
• How to Use the CLI to Configure Features, page 6
Information About Using the Command-Line Interface
Command Modes
The Cisco IOS user interface is divided into many different modes. The commands available to you depend
on which mode you are currently in. Enter a question mark (?) at the system prompt to obtain a list of commands
available for each command mode.
You can start a CLI session through a console connection, through Telnet, an SSH, or by using the browser.
When you start a session, you begin in user mode, often called user EXEC mode. Only a limited subset of
the commands are available in user EXEC mode. For example, most of the user EXEC commands are one-time
commands, such as show commands, which show the current configuration status, and clear commands,
which clear counters or interfaces. The user EXEC commands are not saved when the switch reboots.
To have access to all commands, you must enter privileged EXEC mode. Normally, you must enter a password
to enter privileged EXEC mode. From this mode, you can enter any privileged EXEC command or enter
global configuration mode.
Using the configuration modes (global, interface, and line), you can make changes to the running configuration.
If you save the configuration, these commands are stored and used when the switch reboots. To access the
various configuration modes, you must start at global configuration mode. From global configuration mode,
you can enter interface configuration mode and line configuration mode .
This table describes the main command modes, how to access each one, the prompt you see in that mode, and
how to exit the mode.
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Using the Command-Line Interface
Command Modes
Table 1: Command Mode Summary
Mode
Access Method
User EXEC
Begin a session
using Telnet, SSH,
or console.
Prompt
Switch>
Exit Method
About This Mode
Enter logout or Use this mode to
quit.
• Change
terminal
settings.
• Perform basic
tests.
• Display system
information.
Privileged EXEC
While in user
EXEC mode, enter
the enable
command.
Global
configuration
While in privileged
EXEC mode, enter
the configure
command.
VLAN
configuration
While in global
configuration
mode, enter the
vlan vlan-id
command.
Interface
configuration
While in global
configuration
mode, enter the
interface command
(with a specific
interface).
Switch#
Switch(config)#
Switch(config-vlan)#
Switch(config-if)#
Enter disable
to exit.
Use this mode to
verify commands
that you have
entered. Use a
password to protect
access to this mode.
To exit to
privileged
EXEC mode,
enter exit or
end, or press
Ctrl-Z.
Use this mode to
configure parameters
that apply to the
entire switch.
To exit to
global
configuration
mode, enter the
exit command.
Use this mode to
configure VLAN
parameters. When
VTP mode is
transparent, you can
create
To return to
extended-range
privileged
VLANs (VLAN IDs
EXEC mode,
greater than 1005)
press Ctrl-Z or
and save
enter end.
configurations in the
switch startup
configuration file.
Use this mode to
configure parameters
for the Ethernet
ports.
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Understanding Abbreviated Commands
Mode
Access Method
Prompt
Exit Method
About This Mode
To exit to
global
configuration
mode, enter
exit.
To return to
privileged
EXEC mode,
press Ctrl-Z or
enter end.
Line configuration While in global
configuration
mode, specify a line
with the line vty or
line console
command.
Switch(config-line)#
To exit to
global
configuration
mode, enter
exit.
Use this mode to
configure parameters
for the terminal line.
To return to
privileged
EXEC mode,
press Ctrl-Z or
enter end.
Understanding Abbreviated Commands
You need to enter only enough characters for the switch to recognize the command as unique.
This example shows how to enter the show configuration privileged EXEC command in an abbreviated form:
Switch# show conf
No and Default Forms of Commands
Almost every configuration command also has a no form. In general, use the no form to disable a feature or
function or reverse the action of a command. For example, the no shutdown interface configuration command
reverses the shutdown of an interface. Use the command without the keyword no to reenable a disabled feature
or to enable a feature that is disabled by default.
Configuration commands can also have a default form. The default form of a command returns the command
setting to its default. Most commands are disabled by default, so the default form is the same as the no form.
However, some commands are enabled by default and have variables set to certain default values. In these
cases, the default command enables the command and sets variables to their default values.
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Using the Command-Line Interface
CLI Error Messages
CLI Error Messages
This table lists some error messages that you might encounter while using the CLI to configure your switch.
Table 2: Common CLI Error Messages
Error Message
Meaning
How to Get Help
% Ambiguous command: "show
con"
You did not enter enough
characters for your switch to
recognize the command.
Reenter the command followed by
a question mark (?) without any
space between the command and
the question mark.
The possible keywords that you can
enter with the command appear.
% Incomplete command.
You did not enter all of the
Reenter the command followed by
keywords or values required by this a question mark (?) with a space
command.
between the command and the
question mark.
The possible keywords that you can
enter with the command appear.
% Invalid input detected at
‘^’ marker.
You entered the command
Enter a question mark (?) to display
incorrectly. The caret (^) marks the all of the commands that are
point of the error.
available in this command mode.
The possible keywords that you can
enter with the command appear.
Configuration Logging
You can log and view changes to the switch configuration. You can use the Configuration Change Logging
and Notification feature to track changes on a per-session and per-user basis. The logger tracks each
configuration command that is applied, the user who entered the command, the time that the command was
entered, and the parser return code for the command. This feature includes a mechanism for asynchronous
notification to registered applications whenever the configuration changes. You can choose to have the
notifications sent to the syslog.
Note
Only CLI or HTTP changes are logged.
Using the Help System
You can enter a question mark (?) at the system prompt to display a list of commands available for each
command mode. You can also obtain a list of associated keywords and arguments for any command.
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Using the Help System
SUMMARY STEPS
1. help
2. abbreviated-command-entry ?
3. abbreviated-command-entry <Tab>
4. ?
5. command ?
6. command keyword ?
DETAILED STEPS
Step 1
Command or Action
Purpose
help
Obtains a brief description of the help system in any
command mode.
Example:
Switch# help
Step 2
abbreviated-command-entry ?
Obtains a list of commands that begin with a particular
character string.
Example:
Switch# di?
dir disable disconnect
Step 3
abbreviated-command-entry <Tab>
Completes a partial command name.
Example:
Switch# sh conf<tab>
Switch# show configuration
Step 4
Lists all commands available for a particular command
mode.
?
Example:
Switch> ?
Step 5
command ?
Lists the associated keywords for a command.
Example:
Switch> show ?
Step 6
command keyword ?
Lists the associated arguments for a keyword.
Example:
Switch(config)# cdp holdtime ?
<10-255> Length of time (in sec) that receiver
must keep this packet
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How to Use the CLI to Configure Features
How to Use the CLI to Configure Features
Configuring the Command History
The software provides a history or record of commands that you have entered. The command history feature
is particularly useful for recalling long or complex commands or entries, including access lists. You can
customize this feature to suit your needs.
Changing the Command History Buffer Size
By default, the switch records ten command lines in its history buffer. You can alter this number for a current
terminal session or for all sessions on a particular line. This procedure is optional.
SUMMARY STEPS
1. terminal history [size number-of-lines]
DETAILED STEPS
Step 1
Command or Action
Purpose
terminal history [size number-of-lines]
Changes the number of command lines that the switch records during
the current terminal session in privileged EXEC mode. You can
configure the size from 0 to 256.
Example:
Switch# terminal history size 200
Recalling Commands
To recall commands from the history buffer, perform one of the actions listed in this table. These actions are
optional.
Note
The arrow keys function only on ANSI-compatible terminals such as VT100s.
SUMMARY STEPS
1. Ctrl-P or use the up arrow key
2. Ctrl-N or use the down arrow key
3. show history
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Enabling and Disabling Editing Features
DETAILED STEPS
Command or Action
Purpose
Step 1
Ctrl-P or use the up arrow key
Recalls commands in the history buffer, beginning with the most recent command.
Repeat the key sequence to recall successively older commands.
Step 2
Ctrl-N or use the down arrow key Returns to more recent commands in the history buffer after recalling commands
with Ctrl-P or the up arrow key. Repeat the key sequence to recall successively
more recent commands.
Step 3
show history
Lists the last several commands that you just entered in privileged EXEC mode.
The number of commands that appear is controlled by the setting of the terminal
history global configuration command and the history line configuration
command.
Example:
Switch# show history
Disabling the Command History Feature
The command history feature is automatically enabled. You can disable it for the current terminal session or
for the command line. This procedure is optional.
SUMMARY STEPS
1. terminal no history
DETAILED STEPS
Step 1
Command or Action
Purpose
terminal no history
Disables the feature during the current terminal session in
privileged EXEC mode.
Example:
Switch# terminal no history
Enabling and Disabling Editing Features
Although enhanced editing mode is automatically enabled, you can disable it and reenable it.
SUMMARY STEPS
1. terminal editing
2. terminal no editing
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Enabling and Disabling Editing Features
DETAILED STEPS
Step 1
Command or Action
Purpose
terminal editing
Reenables the enhanced editing mode for the current terminal
session in privileged EXEC mode.
Example:
Switch# terminal editing
Step 2
terminal no editing
Disables the enhanced editing mode for the current terminal
session in privileged EXEC mode.
Example:
Switch# terminal no editing
Editing Commands Through Keystrokes
The keystrokes help you to edit the command lines. These keystrokes are optional.
Note
The arrow keys function only on ANSI-compatible terminals such as VT100s.
Table 3: Editing Commands
Editing Commands
Description
Ctrl-B or use the left arrow key
Moves the cursor back one character.
Ctrl-F or use the right arrow key
Moves the cursor forward one character.
Ctrl-A
Moves the cursor to the beginning of the command
line.
Ctrl-E
Moves the cursor to the end of the command line.
Esc B
Moves the cursor back one word.
Esc F
Moves the cursor forward one word.
Ctrl-T
Transposes the character to the left of the cursor with
the character located at the cursor.
Delete or Backspace key
Erases the character to the left of the cursor.
Ctrl-D
Deletes the character at the cursor.
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Enabling and Disabling Editing Features
Ctrl-K
Deletes all characters from the cursor to the end of
the command line.
Ctrl-U or Ctrl-X
Deletes all characters from the cursor to the beginning
of the command line.
Ctrl-W
Deletes the word to the left of the cursor.
Esc D
Deletes from the cursor to the end of the word.
Esc C
Capitalizes at the cursor.
Esc L
Changes the word at the cursor to lowercase.
Esc U
Capitalizes letters from the cursor to the end of the
word.
Ctrl-V or Esc Q
Designates a particular keystroke as an executable
command, perhaps as a shortcut.
Return key
Scrolls down a line or screen on displays that are
longer than the terminal screen can display.
Note
The More prompt is used for any output that
has more lines than can be displayed on the
terminal screen, including show command
output. You can use the Return and Space
bar keystrokes whenever you see the More
prompt.
Space bar
Scrolls down one screen.
Ctrl-L or Ctrl-R
Redisplays the current command line if the switch
suddenly sends a message to your screen.
Editing Command Lines That Wrap
You can use a wraparound feature for commands that extend beyond a single line on the screen. When the
cursor reaches the right margin, the command line shifts ten spaces to the left. You cannot see the first ten
characters of the line, but you can scroll back and check the syntax at the beginning of the command. The
keystroke actions are optional.
To scroll back to the beginning of the command entry, press Ctrl-B or the left arrow key repeatedly. You can
also press Ctrl-A to immediately move to the beginning of the line.
Note
The arrow keys function only on ANSI-compatible terminals such as VT100s.
The following example shows how to wrap a command line that extends beyond a single line on the screen.
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Searching and Filtering Output of show and more Commands
SUMMARY STEPS
1. access-list
2. Ctrl-A
3. Return key
DETAILED STEPS
Step 1
Command or Action
Purpose
access-list
Displays the global configuration command entry that extends beyond
one line.
Example:
When the cursor first reaches the end of the line, the line is shifted ten
spaces to the left and redisplayed. The dollar sign ($) shows that the
line has been scrolled to the left. Each time the cursor reaches the end
of the line, the line is again shifted ten spaces to the left.
Switch(config)# access-list 101 permit tcp
10.15.22.25 255.255.255.0 10.15.22.35
Switch(config)# $ 101 permit tcp
10.15.22.25 255.255.255.0 10.15.22.35
255.25
Switch(config)# $t tcp 10.15.22.25
255.255.255.0 131.108.1.20 255.255.255.0
eq
Switch(config)# $15.22.25 255.255.255.0
10.15.22.35 255.255.255.0 eq 45
Step 2
Ctrl-A
Checks the complete syntax.
Example:
The dollar sign ($) appears at the end of the line to show that the line
has been scrolled to the right.
Switch(config)# access-list 101 permit tcp
10.15.22.25 255.255.255.0 10.15.2$
Step 3
Return key
Execute the commands.
The software assumes that you have a terminal screen that is 80 columns
wide. If you have a different width, use the terminal width privileged
EXEC command to set the width of your terminal.
Use line wrapping with the command history feature to recall and
modify previous complex command entries.
Searching and Filtering Output of show and more Commands
You can search and filter the output for show and more commands. This is useful when you need to sort
through large amounts of output or if you want to exclude output that you do not need to see. Using these
commands is optional.
SUMMARY STEPS
1. {show | more} command | {begin | include | exclude} regular-expression
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Accessing the CLI on a Switch Stack
DETAILED STEPS
Step 1
Command or Action
Purpose
{show | more} command | {begin | include | exclude}
regular-expression
Searches and filters the output.
Example:
Switch# show interfaces | include protocol
Vlan1 is up, line protocol is up
Vlan10 is up, line protocol is down
GigabitEthernet1/0/1 is up, line protocol is down
GigabitEthernet1/0/2 is up, line protocol is up
Expressions are case sensitive. For example, if you enter
| exclude output, the lines that contain output are not
displayed, but the lines that contain output appear.
Accessing the CLI on a Switch Stack
You can access the CLI through a console connection, through Telnet, a SSH, or by using the browser.
You manage the switch stack and the stack member interfaces through the active switch. You cannot manage
stack members on an individual switch basis. You can connect to the active switch through the console port
or the Ethernet management port of one or more stack members. Be careful with using multiple CLI sessions
on the active switch. Commands that you enter in one session are not displayed in the other sessions. Therefore,
it is possible to lose track of the session from which you entered commands.
Note
We recommend using one CLI session when managing the switch stack.
If you want to configure a specific stack member port, you must include the stack member number in the CLI
command interface notation.
Accessing the CLI Through a Console Connection or Through Telnet
Before you can access the CLI, you must connect a terminal or a PC to the switch console or connect a PC to
the Ethernet management port and then power on the switch, as described in the hardware installation guide
that shipped with your switch.
If your switch is already configured, you can access the CLI through a local console connection or through a
remote Telnet session, but your switch must first be configured for this type of access.
You can use one of these methods to establish a connection with the switch:
• Connect the switch console port to a management station or dial-up modem, or connect the Ethernet
management port to a PC. For information about connecting to the console or Ethernet management
port, see the switch hardware installation guide.
• Use any Telnet TCP/IP or encrypted Secure Shell (SSH) package from a remote management station.
The switch must have network connectivity with the Telnet or SSH client, and the switch must have an
enable secret password configured.
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Accessing the CLI Through a Console Connection or Through Telnet
• The switch supports up to 16 simultaneous Telnet sessions. Changes made by one Telnet user are
reflected in all other Telnet sessions.
• The switch supports up to five simultaneous secure SSH sessions.
After you connect through the console port, through the Ethernet management port, through a Telnet
session or through an SSH session, the user EXEC prompt appears on the management station.
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2
Configuring Flexible NetFlow
• Finding Feature Information, page 13
• Prerequisites, page 14
• Restrictions, page 15
• Restrictions for Flexible NetFlow, page 15
• Restrictions for Wireless Flexible NetFlow, page 17
• Information About NetFlow, page 18
• How to Configure Flexible NetFlow, page 29
• Monitoring Flexible NetFlow, page 44
• Configuration Examples for Flexible NetFlow, page 45
• Additional References, page 47
• Feature Information for Flexible NetFlow, page 49
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 http://www.cisco.com/go/cfn. An account on Cisco.com is not
required.
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Configuring Flexible NetFlow
Prerequisites
Prerequisites
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
◦match flow cts—CTS 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 device and on any interfaces on which you want to enable
Flexible NetFlow: Cisco Express Forwarding or distributed Cisco Express Forwarding.
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Prerequisites for Wireless Flexible NetFlow
IPv6 Traffic
• The networking device must be configured for IPv6 routing.
• One of the following must be enabled on your device and on any interfaces on which you want to enable
Flexible NetFlow: Cisco Express Forwarding IPv6 or distributed Cisco Express Forwarding.
Prerequisites for Wireless Flexible NetFlow
The following are the prerequisites for wireless Flexible NetFlow:
• Ensure that the networking device is running a Cisco release that supports wireless Flexible NetFlow.
• Ensure that the target is connected to a WLAN.
• The networking device must be configured to support protocol types such as IP, IPv6, and datalink.
• Valid flow record and monitor are required before generating the flow.
Restrictions
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; however, the switch can apply a flow monitor to
only one of these types at a time for a given direction and interface.
• 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
8K
16 K
IP Services
8K
16 K
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Configuring Flexible NetFlow
Restrictions for Flexible NetFlow
• 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.
• With the microflow policing feature (which is enabled only for wireless implementation), NetFlow can
and should be used only in full flow mode i.e. NetFlow policing cannot be used. For wireless traffic,
applying a sampler is not permitted, as it hinders microflow QoS.
• Only full flow accounting is supported for wireless traffic.
• 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 63 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, on page
24.
• 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.
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Restrictions for Wireless Flexible NetFlow
Restrictions for Wireless Flexible NetFlow
• Supports up to 24 K NetFlow per ASIC.
• Supports one policy per direction (input and output) per WLAN, which is at the most two monitors per
WLAN.
• Supports only Flexible NetFlow v9 export format.
• The wireless client QoS policy feature shares the NetFlow hardware resource with Flexible NetFlow.
• Use NetFlow only in full flow mode with the QoS policy feature.
• Supports only one flow monitor per interface, per direction.
• Supports Layer 2, IPv4, and IPv6 traffic types. Allows you to apply flow monitor to only one of these
types at a time for a given direction and interface.
• Supports only full flow accounting.
• NetFlow tables cannot be combined because they are on separate compartments. Depending on which
ASIC processed the packet, the flows will be created in the table in the corresponding ASIC.
• Hash collisions occur in the Flexible NetFlow hardware. In spite of the internal overflow CAM, the
actual NetFlow table utilization is about 80 percent.
• Depending on the fields that are used for the flow, a single flow takes two consecutive entries. IPv6
flows also take two entries. So, the effective usage of NetFlow entries is half the table size. This is apart
from the hash collision limitation.
• Supports up to 63 flow monitors. QoS policy uses a separate set of flow monitors.
• The Flexible NetFlow software implementation supports distributed NetFlow export. The flows are
exported from the same switch in which the flow was created.
• Ingress flows are present in the ASIC that received the packets first for the flow. Egress flows are present
in the ASIC from which the packets actually left the switch setup.
• The reported value for the bytes count field (IN_BYTES) is (layer-2-packet-size - 18 bytes). This field
will be accurate only for classic Ethernet traffic. Use the bytes layer2 field, which will always report the
accurate Layer 2 packet size.
• The controller supports three ASICs.
• Supports SSID-based NetFlow accounting.
• For IOS XE release 3E, it is not recommended to use IPFIX IPv4 exporting on the Cisco 5700 Series
Wireless LAN Controller.
• For IOS XE release 3E, following are the limitations on WLAN configurations of egress wireless traffic:
1 If all or some of the WLANs have egress flow monitor configured, then there is no egress microflow
QoS on any WLAN.
2 If all or some of the WLANs have egress microflow QoS defined, then there is no egress flow monitor
configured on any WLAN.
• For IOS XE release 3E, there is support for one WLAN that has egress netflow and egress WQoS enabled
simultaneously.
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Information About NetFlow
Information About NetFlow
NetFlow is a Cisco technology that provides statistics on packets flowing through the switch. NetFlow is the
standard for acquiring IP operational data from IP networks. NetFlow provides data to enable network and
security monitoring, network planning, traffic analysis, and IP accounting. Flexible NetFlow improves on
original NetFlow by adding the capability to customize the traffic analysis parameters for your specific
requirements. Flexible NetFlow facilitates the creation of more complex configurations for traffic analysis
and data export through the use of reusable configuration components.
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 and 10
• 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
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Flow Records
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.
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.
Note
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 Topics
Configuring WLAN to Apply Flow Monitor in IPV4 and IPv6 Input/Output Direction, on page 43
Example: Configuring IPv4 Flexible NetFlow in WLAN (Ingress Direction), on page 45
Example: Configuring IPv6 and Transport Flag Flexible NetFlow in WLAN (Egress Direction), on page
46
Example: Configuring IPv6 Flexible NetFlow in WLAN (Both Ingress and Egress Directions), on page
47
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
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Flow Records
• match wireless—Wireless fields
• match flow cts—CTS fields
Note
The flow monitor with flow record, that contains the CTS field, cannot be attached on the WLAN (SSID).
Related Topics
Creating a Flow Record, on page 29
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 4: 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.
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Flow Records
Command
Purpose
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 | Specifies a match to the Transport Layer fields. The
following command options are available:
source-port}
• 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.
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Flow Records
Command
Purpose
match flow cts {source | destination} group-tag
Specifies a match to the CTS fields support in FNF
record. The following command options are available:
• source —Matches to the source of CTS entering
the domain.
• destination —Matches to the destination of the
CTS leaving the domain.
Flexible NetFlow Collect Parameters
The following table describes the Flexible NetFlow collect parameters.
Table 5: 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.
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Exporters
Exporters
An exporter contains network layer and transport layer details for the Flexible NetFlow export packet.The
following table lists the configuration options for an exporter.
Table 6: Flexible NetFlow Exporter Configuration Options
Exporter Configuration
Description
default
Sets a command to its default values.
description
Provides a description for the flow exporter.
destination
Export destination.
dscp
Optional DSCP value.
exit
Exits from the flow exporter configuration mode.
export-protocol
Export protocol version.
no
Negates the command or its default.
option
Selects option for exporting.
source
Originating interface for the net flow.
template
Flow exporter template configuration.
transport
Transport protocol.
ttl
Optional TTL or hop limit.
• Active timeout—The flow continues to have the packets for the past m seconds since the flow was
created.
• Inactive timeout—The flow does not have any packets for the past n seconds.
Related Topics
Creating a Flow Exporter, on page 32
Export Formats
The switch supports only NetFlow Version 9 export formats. NetFlow Version 9 export format provides the
following features and functionality:
• Variable field specification format
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Configuring Flexible NetFlow
Monitors
• Support for IPv4 destination address export
• More efficient network utilization
Note
For information about the Version 9 export format, see RFC 3954.
Monitors
A monitor references the flow record and flow exporter. You apply a monitor to an interface on the switch .
Note the following when applying a flow monitor to an interface:
• 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.
• 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.
Related Topics
Creating a Flow Monitor, on page 35
Samplers
If you are using sampled mode, you use the sampler to specify the rate at which packets are sampled.
Related Topics
Creating a Sampler, on page 36
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.
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Supported Flexible NetFlow Fields
Field
Layer 2
In
Layer 2
Out
IPv4 In IP v4 Out
Yes
—
Yes
IPv6 In IPv6 Out
Notes
Key or
Collect
Fields
Interface
input
—
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
Flow
direction
Yes
Yes
Yes
Yes
Yes
Yes
Ethertype
Yes
Yes
—
—
—
—
VLAN
input
Yes
—
Yes
—
Yes
—
Notes
Key Fields
Supported
only for a
switch port.
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Supported Flexible NetFlow Fields
Field
Layer 2 In
Layer 2 Out IPv4 In
IP v4 Out
IPv6 In
IPv6 Out
Notes
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
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Supported Flexible NetFlow Fields
Field
Layer 2 In
Layer 2 Out IPv4 In
IP v4 Out
IPv6 In
IPv6 Out
Notes
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
—
—
—
—
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
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.
IPv4
destination
address
Key Fields
continued
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Supported Flexible NetFlow Fields
Field
Layer 2 Out IPv4 In
IP v4 Out
IPv6 In
IPv6 Out
IPv6 source —
address
—
—
—
Yes
Yes
—
—
—
—
Yes
Yes
IPv6
—
traffic-class
—
Yes
Yes
Yes
Yes
Same as IP
TOS.
—
—
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
Yes
Yes
Yes
Yes
Yes
Packet size
= (Ethernet
frame size
including
FCS - 18
bytes)
IPv6
destination
address
IPv6
hop-limit
Layer 2 In
Notes
Collect
Fields
Bytes long
Yes
Recommended:
Avoid this
field and
use Bytes
layer2 long.
Packets
long
Yes
Yes
Yes
Yes
Yes
Yes
Timestamp Yes
absolute
first
Yes
Yes
Yes
Yes
Yes
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Default Settings
Field
Layer 2 In
Layer 2 Out IPv4 In
IP v4 Out
IPv6 In
IPv6 Out
Timestamp Yes
absolute
last
Yes
Yes
Yes
Yes
Yes
TCP flags
Yes
Yes
Yes
Yes
Yes
Yes
Bytes
Yes
layer2 long
Yes
Yes
Yes
Yes
Yes
Notes
Collects all
flags.
Default Settings
The following table lists the Flexible NetFlow default settings for the switch.
Table 7: 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.
Creating a Flow Record
You can create a flow record and add keys to match on and fields to collect in the flow.
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Configuring Flexible NetFlow
Creating a Flow Record
SUMMARY STEPS
1. configure terminal
2. flow record name
3. description string
4. match type
5. collect type
6. end
7. show flow record [name record-name]
8. copy running-config startup-config
DETAILED STEPS
Step 1
Command or Action
Purpose
configure terminal
Enters the global configuration mode.
Example:
Switch# configure terminal
Step 2
flow record name
Creates a flow record and enters flow record configuration
mode.
Example:
Switch(config)# flow record test
Switch(config-flow-record)#
Step 3
description string
(Optional) Describes this flow record as a maximum
63-character string.
Example:
Switch(config-flow-record)# description
Ipv4Flow
Step 4
match type
Specifies a match key.
Example:
Switch(config-flow-record)# match ipv4 source
address
Switch(config-flow-record)# match ipv4
destination address
Switch(config-flow-record)# match flow
direction
Step 5
collect type
Specifies the collection field.
Example:
Switch(config-flow-record)# collect counter
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Creating a Flow Record
Command or Action
Purpose
bytes layer2 long
Note
Switch(config-flow-record)# collect counter
bytes long
Switch(config-flow-record)# collect timestamp
absolute first
Switch(config-flow-record)# collect transport
tcp flags
Switch(config-flow-record)# collect interface output
When a flow monitor has the collect interface output
as the collect field in the flow record, then the output
interface is detected based on the destination address
in the switch. Hence, for the different flow monitors,
the following are required to be configured:
• For ipv4 flow monitor, configure "match ip
destination address"
• For ipv6 flow monitor, configure "match ipv6
destination address"
• For datalink flow monitor, configure "match
datalink mac output"
The collect interface output field will return a value
of NULL when a flow gets created for any of the
following addresses:
• L3 broadcast
• L2 broadcast
• L3 Multicast
• L2 Multicast
• L2 unknown destination.
Step 6
Returns to privileged EXEC mode.
end
Example:
Switch(config-flow-record)#
Step 7
end
show flow record [name record-name]
(Optional) Displays information about NetFlow flow records.
Example:
Switch show flow record test
Step 8
copy running-config startup-config
(Optional) Saves your entries in the configuration file.
Example:
Switch# copy running-config
startup-config
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Configuring Flexible NetFlow
Creating a Flow Exporter
What to Do Next
Define an optional flow exporter by specifying the export format, protocol, destination, and other parameters.
Related Topics
Flow Records, on page 19
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
Step 1
Command or Action
Purpose
configure terminal
Enters the global configuration mode.
Example:
Switch# configure terminal
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Creating a Flow Exporter
Step 2
Command or Action
Purpose
flow exporter name
Creates a flow exporter and enters flow exporter configuration
mode. You can also use this command to modify an existing flow
exporter.
Example:
Switch(config)# flow exporter ExportTest
Step 3
description string
(Optional) Describes this flow record as a maximum 63-character
string.
Example:
Switch(config-flow-exporter)# description
ExportV9
Step 4
destination {ipv4-address|ipv6-address}
Sets the IPv4/IPv6 destination address or hostname for this
exporter.
Example:
Switch(config-flow-exporter)# destination
192.0.2.1 (IPv4 destination)
Switch(config-flow-exporter)# destination
2001:0:0:24::10 (IPv6 destination)
Step 5
dscp value
(Optional) Specifies the differentiated services codepoint value.
The range is from 0 to 63. The default is 0.
Example:
Switch(config-flow-exporter)# dscp 0
Step 6
source { source type }
(Optional) Specifies the interface to use to reach the NetFlow
collector at the configured destination. The following interfaces
can be configured as source:
Example:
Switch(config-flow-exporter)# source
gigabitEthernet1/0/1
• 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
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Configuring Flexible NetFlow
Creating a Flow Exporter
Step 7
Command or Action
Purpose
transport udp number
(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.
Example:
Switch(config-flow-exporter)# transport
udp 200
Step 8
ttl seconds
(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.
Example:
Switch(config-flow-exporter)# ttl 210
Step 9
export-protocol {netflow-v9 | ipfix}
Example:
Specifies the version of the NetFlow export protocol used by the
exporter.
• Default: netflow-v9.
Switch(config-flow-exporter)#
export-protocol netflow-v9
Step 10
Returns to privileged EXEC mode.
end
Example:
Switch(config-flow-record)#
Step 11
end
show flow exporter [name record-name]
(Optional) Displays information about NetFlow flow exporters.
Example:
Switch show flow exporter ExportTest
Step 12
copy running-config startup-config
(Optional) Saves your entries in the configuration file.
Example:
Switch# copy running-config
startup-config
What to Do Next
Define a flow monitor based on the flow record and flow exporter.
Related Topics
Exporters, on page 23
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Configuring Flexible NetFlow
Creating a Flow Monitor
Creating a Flow Monitor
You can create a flow monitor and associate it with a flow record and a flow exporter.
SUMMARY STEPS
1. configure terminal
2. flow monitor name
3. description string
4. exporter name
5. record name
6. cache { timeout {active | inactive} seconds | type normal }
7. end
8. show flow monitor [name record-name]
9. copy running-config startup-config
DETAILED STEPS
Step 1
Command or Action
Purpose
configure terminal
Enters the global configuration mode.
Example:
Switch# configure terminal
Step 2
flow monitor name
Creates a flow monitor and enters flow monitor
configuration mode.
Example:
Switch(config)# flow monitor MonitorTest
Switch (config-flow-monitor)#
Step 3
description string
(Optional) Describes this flow record as a maximum
63-character string.
Example:
Switch(config-flow-monitor)# description Ipv4Monitor
Step 4
exporter name
Associates a flow exporter with this flow monitor.
Example:
Switch(config-flow-monitor)# exporter ExportTest
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Configuring Flexible NetFlow
Creating a Sampler
Step 5
Command or Action
Purpose
record name
Associates a flow record with the specified flow
monitor.
Example:
Switch(config-flow-monitor)# record test
Step 6
cache { timeout {active | inactive} seconds | type normal Associates a flow cache with the specified flow
monitor.
}
Example:
Switch(config-flow-monitor)# cache timeout active
15000
Step 7
Returns to privileged EXEC mode.
end
Example:
Switch(config-flow-monitor)#
Step 8
end
show flow monitor [name record-name]
(Optional) Displays information about NetFlow flow
monitors.
Example:
Switch show flow monitor name MonitorTest
Step 9
copy running-config startup-config
(Optional) Saves your entries in the configuration
file.
Example:
Switch# copy running-config
startup-config
What to Do Next
Apply the flow monitor to a Layer 2 interface, Layer 3 interface, or VLAN.
Related Topics
Monitors, on page 24
Creating a Sampler
You can create a sampler to define the NetFlow sampling rate for a flow.
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Configuring Flexible NetFlow
Creating a Sampler
SUMMARY STEPS
1. configure terminal
2. sampler name
3. description string
4. mode {random}
5. end
6. show sampler [name]
7. copy running-config startup-config
DETAILED STEPS
Step 1
Command or Action
Purpose
configure terminal
Enters the global configuration mode.
Example:
Switch# configure terminal
Step 2
sampler name
Creates a sampler and enters flow sampler
configuration mode.
Example:
Switch(config)# sampler SampleTest
Switch(config-flow-sampler)#
Step 3
description string
(Optional) Describes this flow record as a maximum
63-character string.
Example:
Switch(config-flow-sampler)# description samples
Step 4
mode {random}
Defines the random sample mode.
Example:
Switch(config-flow-sampler)# mode random 1 out-of
1024
Step 5
Returns to privileged EXEC mode.
end
Example:
Switch(config-flow-sampler)#
Step 6
show sampler [name]
end
(Optional) Displays information about NetFlow
samplers.
Example:
Switch show sample SampleTest
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Configuring Flexible NetFlow
Applying a Flow to an Interface
Step 7
Command or Action
Purpose
copy running-config startup-config
(Optional) Saves your entries in the configuration file.
Example:
Switch# copy running-config
startup-config
What to Do Next
Apply the flow monitor to a source interface, subinterface, VLAN interface, or a VLAN.
Related Topics
Samplers, on page 24
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
Step 1
Command or Action
Purpose
configure terminal
Enters the global configuration mode.
Example:
Switch# configure terminal
Step 2
interface type
Enters interface configuration mode and configures an interface.
Command parameters for the interface configuration include:
Example:
• GigabitEthernet—GigabitEthernet IEEE 802
Switch(config)# interface
GigabitEthernet1/0/1
• Loopback—Loopback interface
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Configuring a Bridged NetFlow on a VLAN
Command or Action
Purpose
• 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}
Associate an IPv4 or an IPv6 flow monitor, and an optional
sampler to the interface for input or output packets.
Example:
Switch(config-if)# ip flow monitor
MonitorTest input
Step 4
Returns to privileged EXEC mode.
end
Example:
Switch(config-flow-monitor)#
Step 5
end
show flow interface [interface-type number]
(Optional) Displays information about NetFlow on an interface.
Example:
Switch# show flow interface
Step 6
copy running-config startup-config
(Optional) Saves your entries in the configuration file.
Example:
Switch# copy running-config
startup-config
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
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Configuring Flexible NetFlow
Configuring Layer 2 NetFlow
DETAILED STEPS
Step 1
Command or Action
Purpose
configure terminal
Enters the global configuration mode.
Example:
Switch# configure terminal
Step 2
vlan [configuration] vlan-id
Enters VLAN or VLAN configuration mode.
Example:
Switch(config)# vlan configuration 30
Switch(config-vlan-config)#
Step 3
ip flow monitor monitor name [sampler sampler name] {input Associates a flow monitor and an optional sampler
to the VLAN for input or output packets.
|output}
Example:
Switch(config-vlan-config)# ip flow monitor
MonitorTest input
Step 4
copy running-config startup-config
(Optional) Saves your entries in the configuration
file.
Example:
Switch# copy running-config
startup-config
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
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Configuring Layer 2 NetFlow
DETAILED STEPS
Step 1
Command or Action
Purpose
configure terminal
Enters the global configuration mode.
Example:
Switch# configure terminal
Step 2
flow record name
Enters flow record configuration mode.
Example:
Switch(config)# flow record L2_record
Switch(config-flow-record)#
Step 3
match datalink {dot1q |ethertype | mac | vlan}
Specifies the Layer 2 attribute as a key.
Example:
Switch(config-flow-record)# match datalink ethertype
Step 4
Returns to privileged EXEC mode.
end
Example:
Switch(config-flow-record)#
Step 5
end
show flow record [name ]
(Optional) Displays information about NetFlow
on an interface.
Example:
Switch# show flow record
Step 6
copy running-config startup-config
(Optional) Saves your entries in the configuration
file.
Example:
Switch# copy running-config
startup-config
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Configuring Flexible NetFlow
Configuring WLAN to Apply Flow Monitor in Data Link Input/Output Direction
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
Step 1
Command or Action
Purpose
configure terminal
Enters global configuration mode.
Example:
Switch# configure terminal
Step 2
wlan [wlan-name { wlan-id SSID_NetworkName |
wlan_id} | wlan-name | shutdown}
Example:
Switch (config) # wlan wlan1
Step 3
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.
datalink flow monitor monitor-name {input | output} Applies flow monitor to Layer 2 traffic in the direction of
interest.
Example:
Switch (config-wlan) # datalink flow monitor
flow-monitor-1 {input | output}
Step 4
end
Returns to privileged EXEC mode.
Example:
Switch (config) # end
Step 5
show run wlan wlan-name
(Optional) Verifies your configuration.
Example:
Switch # show wlan mywlan
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Configuring Flexible NetFlow
Configuring WLAN to Apply Flow Monitor in IPV4 and IPv6 Input/Output Direction
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
Step 1
Command or Action
Purpose
configure terminal
Enters global configuration mode
Example:
Switch# configure terminal
Step 2
wlan {wlan-name { wlan-id SSID_NetworkName |
wlan_id} | wlan-name | shutdown}
wlan-id is the wireless LAN identifier. The range is 1 to 64.
SSID_NetworkName is the SSID which can contain 32
alphanumeric characters.
Example:
Switch (config) # wlan wlan1
Step 3
Enters WLAN configuration submode.
{ip | ipv6} flow monitor monitor-name {input |
output}
Note
If you have already configured this command, enter
the wlan wlan-name command.
Associates a flow monitor to the WLAN for input or output
packets.
Example:
Switch (config-wlan) # ip flow monitor
flow-monitor-1 input
Step 4
Returns to privileged EXEC mode.
end
Example:
Switch (config) # end
Step 5
show run wlan wlan-name
(Optional) Verifies your configuration.
Example:
Switch # show wlan mywlan
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Configuring Flexible NetFlow
Monitoring Flexible NetFlow
Related Topics
Wireless Flexible NetFlow Overview, on page 18
Example: Configuring IPv4 Flexible NetFlow in WLAN (Ingress Direction), on page 45
Example: Configuring IPv6 and Transport Flag Flexible NetFlow in WLAN (Egress Direction), on page
46
Example: Configuring IPv6 Flexible NetFlow in WLAN (Both Ingress and Egress Directions), on page
47
Monitoring Flexible NetFlow
The commands in the following table can be used to monitor Flexible NetFlow.
Table 8: 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.
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Configuration Examples for Flexible NetFlow
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)# match flow cts source group-tag
Switch(config-flow-record)# match flow cts destination group-tag
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
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
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
fr_v4
match ipv4 destination address
match ipv4 source address
match ipv4 protocol
match ipv4 tos
match ipv4 ttl
match ipv4 version
match wireless ssid
collect wireless ap mac address
collect counter packets long
collect counter bytes long
collect timestamp absolute first
collect timestamp absolute last
exit
Switch(config)# flow monitor fm_v4
Switch(config-flow-monitor)# record fr_v4
Switch(config-flow-record)# exit
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Configuring Flexible NetFlow
Example: Configuring IPv6 and Transport Flag Flexible NetFlow in WLAN (Egress Direction)
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 Topics
Configuring WLAN to Apply Flow Monitor in IPV4 and IPv6 Input/Output Direction, on page 43
Wireless Flexible NetFlow Overview, on page 18
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
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
Switch(config-flow-record)#
fr_v6
match ipv6 destination address
match ipv6 source address
match ipv6 hop-limit
match ipv6 protocol
match ipv6 traffic
match ipv6 version
match wireless ssid
collect wireless ap mac address
collect counter bytes long
collect transport tcp flags
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 Topics
Configuring WLAN to Apply Flow Monitor in IPV4 and IPv6 Input/Output Direction, on page 43
Wireless Flexible NetFlow Overview, on page 18
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Configuring Flexible NetFlow
Example: Configuring IPv6 Flexible NetFlow in WLAN (Both Ingress and Egress Directions)
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
Switch (config-flow-record)#
Switch (config-flow-record)#
Switch (config-flow-record)#
Switch (config-flow-record)#
Switch (config-flow-record)#
Switch (config-flow-record)#
Switch (config-flow-record)#
Switch (config-flow-record)#
Switch (config-flow-record)#
Switch (config-flow-record)#
fr_v6
match ipv6 destination address
match ipv6 source address
match ipv6 hop-limit
match ipv6 protocol
match ipv6 traffic
match ipv6 version
match wireless ssid
collect wireless ap mac address
collect counter packets long
exit
Switch (config)# flow monitor fm_v6
Switch (config-flow-monitor)# record fr_v6
Switch (config-flow-monitor)# exit
Switch
Switch
Switch
Switch
(config)# wlan
(config-wlan)#
(config-wlan)#
(config-wlan)#
wlan_1
ipv6 flow monitor fm_v6 in
ipv6 flow monitor fm_v6 out
end
Switch# show flow monitor fm_v6 cache
Related Topics
Configuring WLAN to Apply Flow Monitor in IPV4 and IPv6 Input/Output Direction, on page 43
Wireless Flexible NetFlow Overview, on page 18
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)
Cisco Flexible NetFlow Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches)
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Configuring Flexible NetFlow
Additional References
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 http://www.cisco.com/support
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.
Cisco Flexible NetFlow Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches)
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Configuring Flexible NetFlow
Feature Information for Flexible NetFlow
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
Cisco Flexible NetFlow Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches)
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Configuring Flexible NetFlow
Feature Information for Flexible NetFlow
Cisco Flexible NetFlow Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches)
50
OL-28354-02
INDEX
B
I
bridged NetFlow 39
interface configuration 38
C
L
collect parameters 22
Layer 2 NetFlow 40
D
M
default settings 29
match 19
datalink 19
flow 19
interface 19
ipv4 19
ipv6 19
transport 19
match parameters 20
monitoring 44
monitors 24
E
export formats 23
exporters 23
F
flow exporter 32
flow monitor 35
flow record 19, 29
S
sampler 24, 36
Cisco Flexible NetFlow Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches)
OL-28354-02
IN-1
Index
Cisco Flexible NetFlow Configuration Guide, Cisco IOS XE Release 3SE (Catalyst 3850 Switches)
IN-2
OL-28354-02
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