Review Cisco's "NetFlow Performance Analysis" whitepaper to see how turning on NetFlow will affect the performance of your router or switch.

Enable Cisco Express Forwarding:

router(config)# ip cef

In the configuration terminal on the router, issue the following to start NetFlow Export.

It is necessary to enable NetFlow on all interfaces through which traffic you are interested in will flow. Now, verify that the router is generating flow stats - try 'show ip cache flow'. Note that for routers with distributed switching (GSR's, 75XX's) the Rendezvous Point CLI will only show flows that made it up to the RP. To see flows on the individual linecards use the 'attach' or 'if-con' command and issue the 'show ip cache flow' on each LC.

Enable export of these flows with the global commands. 'ip flow-export source' can be set to any interface, but one which is the least likely to enter a 'down' state is preferable. Netflow will not be exported if the specified source is down. For this reason, we suggest the Loopback interface, or a stable Ethernet interface:

router(config)# ip flow-export version 5
router(config)# ip flow-export destination <ip-address> <port>
router(config)# ip flow-export source FastEthernet0

Use the IP address of your NetFlow Collector and configured listening port.

If your router uses BGP protocol, you can configure AS to be included in exports with command:

router(config)# ip flow-export version 5 [peer-as | origin-as]

The following commands break up flows into shorter segments.

router(config)# ip flow-cache timeout active 1
router(config)# ip flow-cache timeout inactive 15

Use the commands below to enable NetFlow on each physical interface (i.e. not VLANs and Tunnels, as they are auto included) you are interested in collecting a flow from. This will normally be an Ethernet or WAN interface. You may also need to set the speed of the interface in kilobits per second. It is especially important to set the speed for frame relay or ATM virtual circuits.

interface <interface>
ip route-cache flow
bandwidth

Now write your configuration with the 'write' or 'copy run start' commands. When in enabled mode, you can see current NetFlow configuration and state with the following commands:

router# show ip flow export
router# show ip cache flow
router# show ip cache verbose flow

Configure the switch the same as an IOS device, but instead of the command

ip route-cache flow

...use the command

ip route-cache flow infer-fields

This series requires a Supervisor Engine IV with a NetFlow Services daughter card to support NDE.

Bandwidth needs to be set explicitly at the VLAN:

ip route-cache flow infer-fields
ip flow ingress infer-fields

Juniper supports flow exports by sampling packet headers with the routing engine and aggregating them into flows. Packet sampling is acheived by defining a firewall filter to accept and sample all traffic, applying that rule to an interface, and then configuring the sampling forwarding option.

interfaces {
 ge-0/1/0 {
	unit 0 {
	   family inet {
		  filter {
			 input all;
			 output all;
		  }
		  address <network>/<mask>  (<- This is in binary notation)
	   }
	}
 }
}
			
firewall {
 filter all {
	term all {
	   then {
		  sample;
		  accept;
	   }
	}
 }
}
			
forwarding-options {
 sampling {
	input {
	   family inet {
		  rate 100;
	   }
	}
	output {
	   cflowd  {
		  port <port>;
		  version <version_number>;
	   }
	}
 }
}
					

For more information on configuring Juniper routers, refer to: http://www.juniper.net.

The following commands are used to configure Netflow Export on Enterasys routers:

netflow set interval 5
netflow set ports all-ports
netflow set collector <ip-address>
netflow enable

For more information, please refer to our "How to Enable NetFlow on an Enterasys SSR" guide or the Enterasys documentation and support at http://www.enterasys.com.

To enable the flow statistics feature on a switch, use the following command:

enable flowstats

The flow statistics feature is disabled by default.

To disable the flow statistics feature on a switch, use the following command:

disable flowstats

To enable the flow statistics function on the specified port, use the following command:

enable flowstats ports <portlist>

The flow statistics function is disabled by default.

To disable the flow statistics function on the specified port, use the following command:

disable flowstats ports <portlist>

A single port can distribute statistics across multiple groups of flow-collector devices. This NetFlow distribution capability makes it possible to create a collection architecture that scales to accommodate high volumes of exported data. It also offers a health-checking function that improves the reliability of the collection architecture by ensuring that only responsive flow-collector devices are included in active export distribution lists. The distribution algorithm also ensures that all the ingress flow records for a given flow are exported to the same collector.

NetFlow distribution is enabled by configuring export distribution groups that identify the addresses of multiple flow-collector devices. You can configure up to 32 export distribution groups on a BlackDiamond 6800 series switch, and each group can contain as many as eight flow-collector devices.

To configure the export groups and flow-collector devices to which NetFlow datagrams are exported, use the following command:

config flowstats export <group#> [add | delete] [<ipaddress> | <hostname>] port <udp_port>

The group# parameter is an integer in the range from 1 through 32 that identifies the specific group for which the destination is being configured.

You can use the add and delete keywords to add or delete flow-collector destinations.

To export NetFlow datagrams to a group, you must configure at least one flow-collector destination. By default, no flow-collector destinations are configured. To configure a flow-collector destination, use either an IP address and UDP port number pair or a hostname and UDP port number pair to identify the flow-collector device to which NetFlow export datagrams are to be transmitted. You can configure up to eight flow-collector destinations for each group. When multiple flow-collectors are configured as members of the same group, the exported NetFlow datagrams are distributed across the available destinations.

To configure the IP address that is to be used as the source IP address for NetFlow datagrams to be exported, use the following command:

config flowstats source <ipaddress>

By default, flow records are exported with the VLAN interface address that has a route to the configured flow-collector device. Depending on how it is configured, a flow-collector device can use the source IP address of received NetFlow datagrams to identify the switch that sent the information.

The following command example specifies that the IP address 192.168.100.1 is to be used as the source IP address for exported NetFlow datagrams.

config flowstats source 192.168.100.1

Flow records are exported on an age basis. If the age of the flow record is greater than the configured time-out, the record is exported.

To configure the time-out value for flow records on the specified port, use the following command:

config flowstats timeout <minutes> ports [<portlist> | any]

The time-out value is the number of minutes to use in deciding when to export flow records. The default time-out is 5 minutes.

The following command example specifies a 10-minute time-out for exported NetFlow datagrams on port 1 of the Ethernet module installed in slot 8 of the BlackDiamond switch.

config flowstats timeout 10 ports 8:1

To reset the flow statistics configuration parameters for a specified Ethernet port to their default values, use the following command:

unconfig flowstats ports <portlist>

To display status information for the flow statistics function, use the following command:

show flowstats {detail | group <group#> | ports <portlist>}

where:

If you enter the show flowstats command with none of the optional keywords or parameters, the command displays a summary of status information for all ports.

The summary status display for a port shows the values for all flow statistics configuration parameters for the port.

The summary status display for an export group includes the following information:

• Values for all configuration parameters
• Status of each export destination device

The detailed status display for an export group includes the summary information, plus the following management information:

• Counts of the number of times each flow collector destination has been taken out of service due to health-check (ping check) failures
• The source IP address configuration information

For more information, please refer to Extreme Networks documentation and support at http://www.extremenetworks.com

The Adtran NetVanta Router supports NetFlow v9. For more information, please refer to the Adtran Web Site.

(config)# ip flow-export destination <ip-addr> interface <int #>
(config)# ip flow-export enable

View more Steelhead commands.

Below are examples of how to enable Traffic-Flow on a router.

1. Enable Traffic-Flow on the router:

[admin@MikroTik] ip traffic-flow> set enabled=yes
[admin@MikroTik] ip traffic-flow> print
				enabled: yes
			 interfaces: all
		  cache-entries: 1k
	active-flow-timeout: 30m
  inactive-flow-timeout: 15s
[admin@MikroTik] ip traffic-flow>
				

2. Specify IP address and port of the host, which will receive Traffic-Flow packets:

[admin@MikroTik] ip traffic-flow target> 
add address=192.168.0.2:2055 \
\... version=9
[admin@MikroTik] ip traffic-flow target> print
Flags: X - disabled
 #   ADDRESS               VERSION
 0   192.168.0.2:2055      9
[admin@MikroTik] ip traffic-flow target>
				

View the PDF Guide, which references the commands to configure sflow on Extreme Switches.

For more Extreme commands, view the ExtremeWare Command Reference Guide.

For information on enabling sFlow on supported HP Procurves, view the ProCurve Networking FAQ.

For information on enabling sFlow on 2800 or 5300 series HP Procurve Switches, download this ZIP file and review the PDF inside for further instructions.

Enter your Scrutinizer server information:

sflow receiver 1 name address udp-port packet-size 1400 version 5 timeout 0

Receiver Name can be set to any one-word string you want (e.g. Scrutinizer). Port should be set to 2055 by default. Packet-size should be set to 1400, version should be 5, and timeout should be 0.

Next, configure a sampler on all desired interfaces:

sflow sampler 1 receiver 1 rate 1 sample-hdr-size 128

So, if you wanted to configure ports 18 and 35 to sample for a switch with a single blade and 48 ports, you would enter:

sflow sampler 1 1/18 receiver 1 rate 1 sample-hdr-size 128
sflow sampler 1 1/35 receiver 1 rate 1 sample-hdr-size 128

Finally, configure one poller to get sFlow counters:

sflow poller 1 receiver 1 interval 5

Write configuration to switch:

write memory

There are only 3 commands to enable sFlow on Foundry gear.

1. Enable it globally
1. (config)# sflow enable
2. Configure a destination
1. (config)# sflow destination x.x.x.x
3. Enable it on port(s)
1. (config)# interface eth 1 (or for multiple ports (config)# interface eth 1 to 48)
2. (config-if-1)# sflow forwarding

For more Foundry commands, view the Foundry Command Reference Guide.

The following commands configure a Force10 switch with IP address 1.1.2.2 to sample at 1-in-512 and send the sFlow packets to Scrutinizer with IP address 1.1.1.1 over UDP port 6343:
config> sflow collector 1.1.1.1 agent-addr 1.1.2.2 sflow sample 512
config> sflow polling 30 sflow enable

Then for each interface:
interface> sflow enable

To list the configuration settings use the command:
show sflow

For information on enabling sFlow on supported D-Link switches, please review the sFlow section of the DGS-36XX User Manual V2.00, as well as our D-Link sFlow Configuration Guide.

View the Netstream Configuration Commands.

NetFlow (AKA NetStream) is supported on the 5000 & 6000 routers via software upgrade and on the 8800 Switch via an NMM module.

To configure NetStream on a 3Com 5012 router, use the following sample configuration:

ip netstream export source interface <Interface>
ip netstream export host <IP address> <port number>

Then activate NetStream on each specific interface you want to obtain statistics from. For example, on the Serial0/0 interface, use the following command.

interface s0/0
ip netstream inbound

This will export inbound NetStream traffic statistics related to the Serial0/0 interface of the 3com router to the workstation running Scrutinizer.

This Configuration Guide shows how to enable IPFIX using Java Device Manager (JDM) or with the Command Line Interface. (See Chapter 4).

NOTE: The 5500 series only supports IP packet sampling resulting in lower than actual utilization trends.