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A NetFlow flow is a unidirectional sequence of packets that arrive on a single interface, and have the same values for key fields.
NetFlow is useful for the following:
Accounting/Billing—NetFlow data provides fine grained metering for highly flexible and detailed resource utilization accounting.
Network Planning and Analysis—NetFlow data provides key information for strategic network planning.
Network Monitoring—NetFlow data enables near real-time network monitoring capabilities.
To perform these configuration tasks, your Cisco IOS XR software system administrator must assign you to a user group associated with a task group that includes the corresponding command task IDs. If you need assistance with your task group assignment, contact your system administrator.
Consider these restrictions when configuring NetFlow in Cisco IOS XR software:
 Tip |
Do not use the management interface to export the NetFlow packets. |
NetFlow can be configured only in the ingress direction.
Netflow v9, IPFIX, and IPFIX 315 support a maximum of two sampler maps.
A source interface must always be configured. If you do not configure a source interface, the exporter will remain in a disabled state.
Only export format Version 9 and IPFIX is supported.
A valid record map name must always be configured for every flow monitor map.
NetFlow is not supported on Bridge Virtual Interface (BVI).
NetFlow on sub-interface routed via BVI is not supported.
Destination-based Netflow accounting is not supported, only IPv4, IPv6 and MPLS record types are supported under monitor-map.
Output interface field is not updated in data and flow records when the traffic is routed through ACL based forwarding (ABF).
Output interface field is not updated in data and flow records for the multicast traffic.
Output interface, source and destination prefix lengths fields are not set in data and flow records for GRE transit traffic.
In-line modification of NetFlow configuration is not supported.
For Netflow IPFIX315, configure the hw-module profile netflow ipfix315 command.
If IPFIX315 is enabled on a line card then all the ports on that line card should have IPFIX315 configured.
For hw-module profile qos hqos-enable , NetFlow does not give the output interface for cases like L2 bridging, xconnect, IPFIX, and so on.
L4 header port numbers are supported only for TCP and UDP.
NetFlow does not give the output interface for traffic terminating on GRE tunnel.
If full packet capture is disabled, then NetFlow captures only IPv4 and IPv6 packets. To enable packet flow for IPv4, IPv6, and L2VPN psuedo wire packets, enable the hw-module profile netflow fpc-enable location command and perform a reload.
If full packet capture is disabled, then NetFlow captures only IPv4 and IPv6 packets. To enable packet flow for IPv4, IPv6, and L2VPN psuedo wire packets, enable the hw-module profile netflow fpc-enable location command and perform a reload.
A flow is exported as part of a NetFlow export User Datagram Protocol (UDP) datagram under these circumstances:
The flow has been inactive or active for too long.
The flow cache is getting full.
One of the counters (packets and or bytes) has wrapped.
The user forces the flow to export.
NetFlow export UDP datagrams are sent to an external flow collector device that provides NetFlow export data filtering and aggregation. The export of data consists of expired flows and control information.
The NetFlow infrastructure is based on the configuration and use of these maps:
Exporter map
Monitor map
Sampler map
These maps are described in the sections that follow.
An exporter map contains user network specification and transport layer details for the NetFlow export packet. The flow exporter-map command allows you to configure collector and version attributes. You can configure these collector information:
Export destination IP address
DSCP value for export packet
Source interface
UDP port number (This is where the collector is listening for NetFlow packets.)
Transport protocol for export packets
 Note |
In Cisco IOS XR Software, UDP is the only supported transport protocol for export packets. |
Note |
NetFlow export packets use the IP address that is assigned to the source interface. If the source interface does not have an IP address assigned to it, the exporter will be inactive. |
You can also configure these export version attributes:
Template timeout
Template data timeout
Template options timeout
Interface table timeout
Sampler table timeout
Note |
A single flow monitor map can support up to eight exporters. |
A monitor map contains name references to the flow record map and flow exporter map. Monitor maps are applied to an interface. You can configure these monitor map attributes:
Number of entries in the flow cache
Type of cache (permanent or normal). Permanent caches do not have their entries removed from the cache unless they are explicitly cleared by the user
Active flow timeout
Inactive flow timeout
Update timeout
Default timeouts
Record type of packets sampled and collected
Note |
The record name specifies the type of packets that NetFlow samples as they pass through the router. Currently, MPLS, IPv4, and IPv6 packet sampling is supported. |
Note |
The active flow and inactive flow timeouts are associated with a normal cache type. The update timeout is associated with the permanent cache type. |
|
Feature Name |
Release Information |
Description |
|---|---|---|
|
Enhanced NetFlow Sampling Rate of 1:2048 (2K) |
Release 7.4.1 |
You can configure a sampling rate of 1:2048 on NC57 line card when the line card is configured in the native mode. Previously, the line card supported configuring Netflow sampling rate of 1:4096(4K), 1:8192(8K), and 1:16384(16K) The command random 1 out-of is modified to support the new sampling rate. |
The sampler map specifies the rate at which packets (one out of n packets) are sampled. The sampler map configuration is typically geared for high-speed interfaces to optimize CPU utilization. To achieve this, start by setting the sampling rate after evaluating your network parameters such as traffic rate, number of total flows, cache size, active and inactive timers.
The maximum supported sampling rate is 1:1, where every packet is processed.
The minimum supported sampling rate is 1:65,536, indicating that only one out of every 65,536 packets is processed.
Consider these points before applying sampler map:
Remove the existing Netflow configurations before applying a new sampler map on an already existing netflow interface configuration.
Sub-interfaces and physical interfaces under a port must have the same sampler map configuration.
Note |
While caching netflow traffic over bundle interface, a deviation in flow monitor cache entries is observed. The deviation is not always consistent, and the acceptable limit is up to 15% |
Consider these points before applying sampler map:
You must remove the existing netflow configuration before applying a new sampler map on an already existing netflow interface configuration.
Sub-interfaces and physical interfaces under a port must have the same sampler map configuration.
The In-line modification of Netflow configuration enables to add or remove flow attributes of a flow entity that is already applied to an interface.
A flow entity can be a monitor map, exporter map or a sampler map.
Netflow does not support in-line modification of all its configuration items. This table lists flow entries and flow attributes that are in-line modifiable.
Note |
In-line modification of flow items clears the cache counters. As a result there could be flow accounting mismatch. |
Note |
The In-line modification of Netflow configuration is supported on Cisco IOS XR 64 bit software. |
|
Flow Entity |
Flow Attribute |
||
|---|---|---|---|
|
Monitor map
|
cache timeout active seconds |
||
|
cache timeout inactive seconds |
|||
|
cache timeout update seconds |
|||
|
cache timeout rate-limit seconds |
|||
|
exporter |
|||
|
cache entries |
|||
|
cache permanent |
|||
|
option outphysint | bgstrings
|
|||
|
Exporter Map
|
source <source interface> |
||
|
destination <destinaiton address> |
|||
|
dscp <dscp_value> |
|||
|
version v9 | ipfix |
|||
|
Sampler Map |
sampling interval |
In-line modification of the record ipv4 flow attribute is not supported.
Consider a netflow configuration as shown below applied on Bundle interface.
RP/0/RP1/CPU0:router#show running-config interface bundle-ether 8888
Thu Oct 26 14:17:17.459 UTC
interface Bundle-Ether8888
ipv4 address 192.168.108.1 255.255.255.252
ipv6 address 192:168:108::1/126
flow ipv6 monitor MONITOR-8k sampler SAMPLER-8k ingress
!
RP/0/RP1/CPU0:router#show running-config flow monitor-map MONITOR-8k
Thu Oct 26 14:17:32.581 UTC
flow monitor-map MONITOR-8k
record ipv6
exporter NF-2
cache timeout update 30
!
The Netflow configuration includes:
flow monitor map—MONITOR-8k: The flow monitor map do not have cache entries configured. Cache entries are the number of entries in the flow cache.
exporter map—NF-2
sampler map—SAMPLE-8k
The cache entries attribute is in-line modifiable. Let us configure the cache entries, while the flow monitor map is in use:
RP/0/RP1/CPU0:router#config
RP/0/RP1/CPU0:router(config)#flow monitor-map MONITOR-8k
RP/0/RP1/CPU0:router(config-fmm)#cache entries 8000
RP/0/RP1/CPU0:router(config-fmm)#commit
Thu Oct 26 14:18:24.625 UTC
RP/0/RP1/CPU0:Oct 26 14:18:24.879 : config[67366]: %MGBL-CONFIG-6-DB_COMMIT : Configuration committed by user '<username>'.
Use 'show configuration commit changes 1000000556' to view the changes. /*configuration commit is successfull. */
The above configuration changes are committed successfully.
To verify if the monitor map has chache entries of 8000 configured, use the show flow monitor-map command for MONITOR-8k map:
RP/0/RSP0/CPU0:router# show flow monitor-map MONITOR-8k
Flow Monitor Map : MONITOR-8k
-------------------------------------------------
Id: 1
RecordMapName: ipv6
ExportMapName: NF-2
CacheAgingMode: Permanent
CacheMaxEntries: 8000
CacheActiveTout: N/A
CacheInactiveTout: N/A
CacheUpdateTout: 30 secondsNetFlow version 9 is a template-based version. The templates provide an extensible design to the record format. This feature allows enhancements to NetFlow services without requiring concurrent changes to the basic flow-record format. An options template is a special type of template record that is used to communicate the format of data related to the NetFlow process. Rather than supplying information about IP flows, the options are used to supply metadata about the NetFlow process itself. The sampler options template and the interface options template are different forms of options templates. These two tables are exported by the NetFlow process. The NetFlow process will also export the VRF table.
The sampler options template consists of sampler tables. Similarly, the interface option templates consist of interface tables. By enabling the options for sampler table and interface table, it becomes easier for the collector to determine the information on data flow.
| Field Name | Value |
|---|---|
|
FlowSamplerID |
This ID is assigned to the sampler. It is used by the collector to retrieve information about the sampler for a data flow record. |
|
FlowSamplerMode |
This field indicates the mode in which the sampling has been performed. |
|
FlowSamplerRandomInterval |
This field indicates the rate at which the sampling is performed. |
|
SamplerName |
This field indicates the name of the sampler. |
The interface table consists of information on interfaces that are being monitored for data flow. By using this information, the collector determines the names of interfaces associated with the data flow. The interface table consists of the following information:
| Field Name | Value |
|---|---|
|
ingressInterface |
This field indicates the SNMP index assigned to the interface. By matching this value to the Ingress interface in the data flow record, the collector is able to retrieve the name of the interface. |
|
interfaceDescription |
This field indicates the name of the interface. |
The VRF table consists of mapping of VRF IDs to the VRF names. By using this information, the collector determines the name of the required VRF. The VRF table consists of the following information:
| Field Name | Value |
|---|---|
|
ingressVRFID |
The identifier of the VRF with the name in the VRF-Name field. |
|
VRF-Name |
The VRF name which has the VRFID value ingressVRFID. The value "default" indicates that the interface is not assigned explicitly to a VRF. |
The data records contain ingressVRFID as an extra field in each record. The values of these fields are used to lookup the VRF Table to find the VRF names. A value 0 in these fields indicates that the VRF is unknown.
The VRF table is exported at intervals specified by the optional timeout keyword that can be configured manually. The default value is 1800 seconds.
|
Feature Name |
Release Information |
Feature Description |
|---|---|---|
|
Flow Filter on Cisco NC57 Line Cards |
Release 7.2.2 |
With this feature, you can collect user-defined and ACL-filtered NetFlow data that is available in the NetFlow cache and export it to an external interface for processing. Flow filter can be configured on interfaces in ingress direction. This feature introduces the option filtered command. |
NetFlow provides highly granular per-flow traffic statistics in a Cisco router. The router accumulates NetFlow statistics of all the flows in a NetFlow cache and exports them to an external device for further processing. But in some cases, you might want to gather NetFlow data on only a subset of these flows. The flow filter feature provides the capability to gather NetFlow data on only a specific user-defined subset of flow.
The flow filter feature is configured on interfaces in ingress or egress direction. The flow filter feature uses ACL and QoS bits to filter the NetFlow data; the match criteria is based on five tuple and DSCP bits. The filtered Netflow data is sampled (not all interface flows are sampled) and exported to a collector.
When both security ACL and Netflow filtering ACL are configured on an interface, the security ACL takes precedence over Netflow filtering ACL.
The Flow Filter supports:
NetFlow v9 and IPFIX export formats.
Yang data model for dynamic provisioning.
These are the restrictions for the flow filter feature:
Supported on physical interface, physical subinterface, bundle interface, and bundle subinterface
Not supported on satellite access interface, ICL interface and clusters.
MPLS netflow filtering is not supported.
Consider SP-PE use case where SP (Service Provide) cloud is connected to the PE (Provider Edge) router through gigabit ethernet.
Configuring NetFlow on PE router involves:
Configuring ACL based filter criteria for NetFlow
Configuring Monitor map with filter netflow object
Configuring Sampler map
Configuring Exporter map
Applying the NetFlow flow filter ACL configuration and Monitor map to an interface
ipv4 access-list nf_ex
10 permit ipv4 192.168.1.1/24 any capture
flow monitor-map fmm1
record ipv4
option filtered
exporter fem1
cache entries 10000
cache timeout active 1800
cache timeout inactive 15
exit
sampler-map fsm1
random 1 out-of 65535
exit
flow exporter-map fem1
destination 10.1.1.1
source Loopback 0
transport udp 1024
dscp 10
exit
version v9
template data timeout 600
options interface-table
exit
interface 10GE0/0/0/1
ipv4 access-group nf_ex_ing
flow ipv4 monitor fmm1 sampler fsm1 ingress
exit
Use the show flow monitor command to verify the flow filter configuration successfully applied on the PE router:
RP/0/RP0/CPU0:router# show flow monitor-map netflow_monitor_map_fl_4
Flow Monitor Map : netflow_monitor_map_fl_4
-------------------------------------------------
Id: 28
RecordMapName: ipv4-raw
ExportMapName: netflow_exporter_map_fl_4
CacheAgingMode: Normal
CacheMaxEntries: 65535
CacheActiveTout: 1800 seconds
CacheInactiveTout: 700 seconds
CacheUpdateTout: N/A
CacheRateLimit: 2000
Options: filtered
HwCacheExists: False
HwCacheInactTout: 50
Flow Monitor : fmm1
---------------------------------------------
Flow definition: ipv4-raw
Cache configuration:
Type: Normal
Cache size: 65535 entries
Inactive timeout: 15 seconds
Active timeout: 1800 seconds
Update timeout: N/A
Rate limit: 2000 entries per second
Options: filtered
Internet Protocol Flow Information Export (IPFIX) has been standardized by the Internet Engineering Task Force (IETF) as an export protocol for transmitting NetFlow packets. Building upon NetFlow version 9, IPFIX introduces efficient flow data formatting through templates, ensuring scalability and adaptability to diverse network environments. Utilizing UDP as the transport protocol, IPFIX facilitates the seamless transfer of NetFlow information from exporters to collectors. With native support for IPv6 flow records, the inclusion of optional data fields, and the ability to send data to multiple collectors, IPFIX proves to be a versatile and powerful solution for network administrators, enabling comprehensive traffic analysis, monitoring, and enhanced visibility into network behavior.
These IPFIX features are not supported:
Variable-length information element in the IPFIX template
Stream Control Transmission Protocol (SCTP) as the transport protocol
You cannot modify an exporter version of an exporter map that is already applied to an interface. To modify the exporter version, first remove the exporter configuration applied on the interface, later modify the version and apply the configuration to the interface.
An interface can have three different monitor-maps but all the monitor maps should have the same version for the exporters. There can be different exporters for the three monitor maps but they all need to have the same exporter version either v9 or IPFIX.
You can only have monitor-maps one of each record type attached to an interface, that is one monitor-map for IPv4 record, one monitor-map for IPv6 record and one for MPLS record. There can be different exporter maps for these three monitor-maps but all the exporter maps should have same exporter version configured, either v9 or IPFIX.
Multiple sampler-maps can be configured but only two sampler maps can be appled to an interface across the system.
Consider SP-PE use case where SP (Service Provider) cloud is connected to the PE (Provider Edge) router through TenGigabit ethernet.
Configuring NetFlow on PE router involves:
Configuring Exporter map with IPFIX as an exporter
Configuring Monitor map
Configuring Sampler map
Applying the Monitor map and Sampler map to an interface
flow exporter-map fem_ipfix
destination 10.1.1.1
source Loopback 0
transport udp 1025
exit
version ipfix
template data timeout 600
options sampler-table
exit
flow monitor-map fmm1
record ipv4
option filtered
exporter fem_ipfix
cache entries 10000
cache timeout active 1800
cache timeout inactive 15
exit
sampler-map fsm1
random 1 out-of 4000 /*Sampling rate supported is 1:4000*/
exit
configure
interface 10GE0/0/0/1
flow ipv4 monitor fmm1 sampler fsm1 ingress
exit
Use the show flow flow-exporter map command to verify the exporter version configured is IPFIX:
RP/0/RP0/CPU0:router# show flow exporter-map fem_ipfix
Flow Exporter Map : fem_ipfix
-------------------------------------------------
Id : 3
Packet-Length : 1468
DestinationIpAddr : 10.1.1.1
VRFName : default
SourceIfName : Loopback1
SourceIpAddr : 4.4.0.1
DSCP : 40
TransportProtocol : UDP
TransportDestPort : 9001
Export Version: IPFIX
Common Template Timeout : 1800 seconds
Options Template Timeout : 1800 seconds
Data Template Timeout : 1800 seconds
Interface-Table Export Timeout : 0 seconds
Sampler-Table Export Timeout : 0 seconds
VRF-Table Export Timeout : 0 seconds
Exported packets in an IPFIX packet structure are in the form of template set or data set. The first data template is sent when the configuration is activated on the interface.
With constant stream, the flowset data does not change, so data is decoded. Data template is updated in the case of timeout
on the template. To change the timeout options in the flow exporter, use the template options timeout command:
RP/0/RP0/CPU0:router(config)#flow exporter-map ipfix_exp1
RP/0/RP0/CPU0:router(config-fem)#version ipfix
RP/0/RP0/CPU0:router(config-fem-ver)#template options
RP/0/RP0/CPU0:TU-PE3(config-fem-ver)#template options timeout
RP/0/RP0/CPU0:TU-PE3(config-fem-ver)#template options timeout 30
RP/0/RP0/CPU0:router# show flow exporter-map ipfix_exp1
version ipfix
template data timeout 30
!
dscp 40
transport udp 9001
source Loopback0
destination 10.127.59.86Internet Protocol Flow Information Export (IPFIX) is an IETF standard export protocol (RFC 7011) for sending IP flow information. Cisco NCS 5500 Router supports IPFIX 315 format to export flow information. IPFIX 315 format facilitates sending ‘n’ octets frame information starting from ethernet header till transport header of the traffic flow over the network. IPFIX 315 supports sending variable size packet record with variable payload information such as IPv4, IPv6, MPLS, and Nested packets like OuterIP-GRE-InnerIP and so on. The process includes sampling and exporting the traffic flow information. Along with the ethernet frame information, IPFIX 315 format exports information of incoming and outgoing interface of the sampled packet.
Use hw-module profile netflow ipfix315 location < linecard location > command to enable IPFIX 315.
The information of the packets flowing through a device is used for variety of purpose including network monitoring, capacity planning, traffic management, and so on,
Note |
Cisco NCS 5500 Router does not support Netflow version 9 format to export flow information. |
You must configure a sampling map to sample the traffic flow information. The sampler map specifies the rate at which packets (one out of n packets) are sampled. The minimun sampling rate is 1 out of 32,000 packets. Not all packets flowing through a device are exported; packets selected as per sampling rate are considered for exporting.
You must configure a sampling map to sample the traffic flow information. The sampler map specifies the rate at which packets (one out of n packets) are sampled.
The size of exported packet is untill and including L4 header.
The below figure IPFIX 315 Export Packet Format shows exported packet information.
A special cache type called Immediate Aging is used while exporting the packets. Immediate Aging ensures that the flows are exported as soon as they are added to the cache. Use the command cache immediate in flow monitor map configuration to enable Immediate Aging cache type.
Here are few key points to consider before implementing IPFIX 315:
Supported only in ingress direction.
Supported on main interface only. The traffic on all sub-interfaces under the main interface is exported.
Sampling rate for bundles is per member-link and not per bundle interface.
The outgoing interface information may not be correct incase of packets that are multicasted or broadcasted on multiple ports.
The incoming and outgoing interface will have information of main interface and not the sub-interface even if the packet is routed via sub-interface. Incase of bundles it will point to bundle main interface.
IPFIX 315 is not supported on BVI interface.
Sampling and exporting of the control packets is not supported.
When you configure ipfix315-enable, then you must configure all the ports on that LC with datalinkframesection flow.
When the HQoS profile is enabled, Netflow does not give correct Output Interface. DSP is unique for each sub-interface.
Netflow on the L2 interface assumes IPv4/IPv6/MPLS traffic, and if the traffic is purely L2 based, then the system ignores that traffic.
You must remove all v9 configurations before reloading an LC. Else, with the existing v9 configurations on LC reload, you might encounter a few configuration apply error. Or, flow might be seen on an interface even when apply on interface has failed.
Configuring IPFIX 315 involves:
Configuring Exporter map
Configuring Monitor map
Configuring Sampler map
Enabling IPFIX 315 on a line card
Applying the Monitor map and Sampler map to an interface
flow exporter-map ipfix_exp
version ipfix
!
dscp 40
transport udp 9001
source Loopback1
destination 100.10.1.159
!
Note |
For options command and its configurations in Exporter Map, see options. |
flow monitor-map ipfix_mon
record datalinksectiondump
exporter ipfix_exp
cache immediate
cache entries 1000000
cache timeout rate-limit 1000000
!
sampler-map ipfix_sm
random 1 out-of 32000
!
Note |
The default cache size is 65535, hence you can configure sampling rate as 1 out of 65535 packets. However the recommended sampling rate is 1 out of 32000 packets. |
(config)# hw-module profile netflow ipfix315-enable location 0/0/CPU0 You should reload the LC for the changes to take effect.
interface HundredGigE 0/0/0/18
flow datalinkframesection monitor ipfix_mon sampler ipfix_sm ingress
RP/0/RP0/CPU0#show flow platform producer statistics location 0/0/CPU0
Netflow Platform Producer Counters:
IPv4 Ingress Packets: 0
IPv4 Egress Packets: 0
IPv6 Ingress Packets: 0
IPv6 Egress Packets: 0
MPLS Ingress Packets: 0
MPLS Egress Packets: 0
IPFIX315 Ingress Packets: 630478
IPFIX315 Egress Packets: 0
Drops (no space): 0
Drops (other): 0
Unknown Ingress Packets: 0
Unknown Egress Packets: 0
Worker waiting: 2443
RP/0/RP0/CPU0#show flow monitor ipfix_mon cache location 0/0/CPU0
Cache summary for Flow Monitor ipfix_mon:
Cache size: 65535
Current entries: 0
Flows added: 50399
Flows not added: 0
Ager Polls: 2784
- Active timeout 0
- Inactive timeout 0
- Immediate 50399 /*cache type immediate*/
- TCP FIN flag 0
- Emergency aged 0
- Counter wrap aged 0
- Total 50399
Periodic export:
- Counter wrap 0
- TCP FIN flag 0
Flows exported 50399
Matching entries: 0
Above example shows that there were 50399 flows added to the cache and exported.
In Cisco IOS XR Software, NetFlow map configuration takes place in map-specific submodes. Cisco IOS XR Software supports these NetFlow map configuration submodes:
Note |
The Cisco IOS XR Software allows you to issue most commands available under submodes as one single command string from mode. For example, you can issue the record ipv4 command from the flow monitor map configuration submode as follows: |
RP/0/RP0/CPU0:router(config)# flow monitor-map fmm
RP/0/RP0/CPU0:router(config-fmm)# record ipv4
Alternatively, you can issue the same command from global configuration mode, as shown in the following example:
RP/0/RP0/CPU0:router(config)# flow monitor-map fmm record ipv4
When you issue the flow monitor-map map_name command in mode, the CLI prompt changes to “config-fmm,” indicating that you have entered the flow monitor map configuration submode.
In this sample output, the question mark (?) online help function displays all the commands available under the flow monitor map configuration submode:
RP/0/RP0/CPU0:router(config)# flow monitor-map fmm
RP/0/RP0/CPU0:router(config-fmm)# ?
cache Specify flow cache attributes
commit Commit the configuration changes to running
describe Describe a command without taking real actions
do Run an exec command
exit Exit from this submode
exporter Specify flow exporter map name
no Negate a command or set its defaults
record Specify a flow record map name
show Show contents of configuration
When you issue the flow exporter-map fem-name command in mode, the command-line interface (CLI) prompt changes to “config-fem,” indicating that you have entered the flow exporter map configuration submode.
In this sample output, the question mark (?) online help function displays all the commands available under the flow exporter map configuration submode:
RP/0/RP0/CPU0:router(config)# flow exporter-map fem
RP/0/RP0/CPU0:router(config-fem)# ?
clear Clear the uncommitted configuration
clear Clear the configuration
commit Commit the configuration changes to running
describe Describe a command without taking real actions
destination Export destination configuration
do Run an exec command
dscp Specify DSCP value for export packets
exit Exit from this submode
no Negate a command or set its defaults
pwd Commands used to reach current submode
root Exit to the global configuration mode
router-id router-id or agent-id configuration
show Show contents of configuration
source Source interface
transport Specify the transport protocol for export packets
version Specify export version parametersNote |
If you enter the version command, you enter the flow exporter map version configuration submode. |
Note |
A single flow monitor map can support up to eight exporters. |
When you issue the version v9 command in the flow exporter map configuration submode, the CLI prompt changes to “config-fem-ver,” indicating that you have entered the flow exporter map version configuration submode.
In this sample output, the question mark (?) online help function displays all the commands available under the flow exporter map version configuration submode:
RP/0/RP0/CPU0:router(config-fem)# version v9
RP/0/RP0/CPU0:router(config-fem-ver)# ?
commit Commit the configuration changes to running
describe Describe a command without taking real actions
do Run an exec command
exit Exit from this submode
no Negate a command or set its defaults
options Specify export of options template
show Show contents of configuration
template Specify template export parameters
When you issue the sampler-map map_name command in mode, the CLI prompt changes to “config-sm,” indicating that you have entered the sampler map configuration submode.
In this sample output, the question mark (?) online help function displays all the commands available under the sampler map configuration submode:
RP/0/RP0/CPU0:router(config)# sampler-map fmm
RP/0/RP0/CPU0:router(config-sm)# ?
clear Clear the uncommitted configuration
clear Clear the configuration
commit Commit the configuration changes to running
describe Describe a command without taking real actions
do Run an exec command
exit Exit from this submode
no Negate a command or set its defaults
pwd Commands used to reach current submode
random Use random mode for sampling packets
root Exit to the global configuration mode
show Show contents of configuration
Use the bgp attribute-download command to enable NetFlow BGP routing attribute collection. The routing attributes are then exported. When no routing attributes are collected, zeroes (0) are exported.
When BGP attribute download is enabled, BGP downloads the attribute information for prefixes (community, extended community, and as-path) to the Routing Information Base (RIB) and Forwarding Information Base (FIB). This enables FIB to associate the prefixes with attributes and send the NetFlow statistics along with the associated attributes.
Cisco IOS XR Software supports the NetFlow collection of MPLS packets. It also supports the NetFlow collection of MPLS packets carrying IPv4, IPv6, or both IPv4 and IPv6 payloads.
In Cisco IOS XR Software, at a time, you can have only one MPLS flow monitor running on an interface. If you apply an additional MPLS flow monitor to the interface, the new flow monitor overwrites the existing one.
You can configure the MPLS flow monitor to collect IPv4 fields, IPv6 fields, or IPv4-IPv6 fields. IPv4-IPv6 configuration collects both IPv4 and IPv6 addresses using one MPLS flow monitor. IPv4 configuration collects only IPv4 addresses. IPv6 configuration collects only IPv6 addresses.
The MPLS flow monitor supports up to 1,000,000 cache entries. NetFlow entries include these types of fields:
IPv4 fields
IPv6 fields
MPLS with IPv4 fields
MPLS with IPv6 fields
The maximum number of bytes per NetFlow cache entry is as follows:
IPv4–88 bytes per entry
IPv6–108 bytes per entry
MPLS with IPv4 fields–108 bytes per entry
MPLS with IPv6 fields–128 bytes per entry
Note |
The different types of NetFlow entries are stored in separate caches. Consequently, the number of NetFlow entries on a line card can significantly impact the amount of available memory on the line card. Also, even though the sampling rate for IPv6 is the same as the sampling rate for IPv4, the CPU utilization for IPv6 is higher due to the longer keys used by the IPv6 fields. |
|
Feature Name |
Release Information |
Feature Description |
|---|---|---|
| MPLS top label type 4 for BGP Labeled Unicast traffic | Release 7.4.1 |
This feature is an enhancement to how Netflow MPLS records are verified. This feature allows the user to analyze the traffic types by providing more visibility on the granularity of the information. This feature helps you to monitor the traffic data. This feature introduces the new MPLS label type BGP. This label type is a field in the MPLS label that identifies the control protocol which allocates the top-of-stack label. MPLS label types enable verification of Netflow MPLS records. |
The collection of IPv6 flows in MPLS packets is an option. The CPU uses 128 bytes for each IPv6 field. IPv6 flows may contain these types of information:
Source IP address
Destination IP address
Traffic class value
Layer 4 protocol number
Layer 4 source port number
Layer 4 destination port number
Flow ID
Header option mask
To collect the IPv6 fields in MPLS packets, you must activate the MPLS record type, ipv6-fields by running the record mpls ipv6-fields command. You can also specify the number of labels to be used for aggregation with this command.
MPLS packets sampled by the netflow monitor export the label type based on the topmost label type in the netflow cache record. When the topmost record is an explicit NULL, the succeeding label type is accounted.
The Top label type 4 for BGP Labeled Unicast traffic feature is an enhancement to how netflow MPLS records are verified. MPLS label type value 4, which indicates any label associated with BGP or BGP routing, is supported starting from Release 7.4.1. Earlier to this release, the label type was exported as 0, indicating unknown.
This feature provides the user with additional support for analysis of traffic types by providing more visibilty on the granularity of information. This feature provides clearer perspective on data monitoring.
|
Value |
Description |
Supported available |
|---|---|---|
|
0 |
Unknown: The MPLS label type is not known |
Yes |
|
1 |
TE-MIDPT: Any TE tunnel mid-point or tail label |
No |
|
2 |
Pseudowire: Any PWE3 or Cisco AToM-based label |
No |
|
3 |
VPN: Any label associated with VPN |
No |
|
4 |
BGP: Any label associated with BGP or BGP routing |
Yes |
|
5 |
LDP: Any label associated with dynamically assigned labels using LDP |
Yes |
|
6-255 |
Unassigned |
No |
This feature captures the exact packet size of the ingress Netflow packet.
Earlier, when a L2VPN packet with a destination MAC address starting with the number 6 is received, the packet gets wrongly decoded as IPv6 packet; the packet size consequently gets reported inaccurately to the collector.
This section describes how to configure Netflow full packet capture feature on the line card location 0/1/cpu0:
Note |
You should reload the line card for the changes to take effect. |
RP/0/RP0/CPU0:router(config)# hw-module profile netflow fpc-enable location 0/1/cpu0
RP/0/RP0/CPU0:router(config)# exit
RP/0/RP0/CPU0:router # system admin
RP/0/RP0/CPU0:router(sysadmin)# hw-module reload location 0/1/cpu0
RP/0/RP0/CPU0:router(sysadmin)# commit
RP/0/RP0/CPU0:router(sysadmin)# end
config
hw-module profile netflow fpc-enable location 0/1/cpu0
!
sysadmin
hw-module reload location 0/1/cpu0
! The steps that follow provide a general overview of NetFlow configuration:
Note |
We recommend that you not use the default ethernet VLAN (VLAN-1) in any of your network configurations. Traffic tagged with VLAN-1 may cause conflicts with other configurations. |
|
Step 1 |
Create and configure an exporter map. |
||
|
Step 2 |
Create and configure a monitor map and a sampler map.
|
||
|
Step 3 |
Apply the monitor map and sampler map to an interface. These steps are described in detail in these sections: |
Configure an exporter map and apply it to the monitor map with the flow monitor-map map_name exporter map_name command. You can configure the exporter map prior to configuring the monitor map, or you can configure the monitor map first and then configure and apply an exporter map later on.
Note |
Cisco IOS XR Software supports the configuration of a single collector only in the exporter map. |
The steps that follow describe how to create and configure an exporter map and enable exporting of the sampler table or the interface table.
|
Step 1 |
configure Example:Enters global configuration mode. |
|
Step 2 |
flow exporter-map map_name Example:Creates an exporter map, configures the exporter map name, and enters flow exporter map configuration mode. |
|
Step 3 |
destination hostname_or_IP_address [ vrf vrf-name] Example:Configures the export destination for the flow exporter map. The destination can be a hostname, a VRF, or an IPv4/IPv6 address. |
|
Step 4 |
dscp dscp_value Example:(Optional) Specifies the differentiated services codepoint (DSCP) value for export packets. Replace the dscp_value argument with a value in the range from 0 through 63. |
|
Step 5 |
source type interface-path-id Example:Specifies a source interface, in the format type interface-path-id . |
|
Step 6 |
transport udp port Example:(Optional) Specifies the destination port for UDP packets. Replace port with the destination UDP port value, in the range from 1024 through 65535. |
|
Step 7 |
version v9 Example:(Optional) Enters flow exporter map version configuration submode. |
|
Step 8 |
options {interface-table | sampler-table | vrf-table} [timeout seconds] Example:(Optional) Configures the export timeout value for the sampler table. Replace seconds with the export timeout value, in the range from 1 through 604800 seconds. Default is 1800 seconds. |
|
Step 9 |
template [data | options] timeout seconds Example:(Optional) Configures the export period for data packets. Replace seconds with the export timeout value, in the range from 1 through 604800 seconds. |
|
Step 10 |
commit |
|
Step 11 |
exit Example:Exits flow exporter map version configuration submode. |
|
Step 12 |
exit Example:Enters XR EXEC mode. |
|
Step 13 |
show flow exporter-map map_name Example:Displays exporter map data. |
This example shows how to create a new flow exporter map called “fem1,” which uses the version 9 (V9) export format for NetFlow export packets. The data template flow-set is inserted into the V9 export packets once every 10 minutes, and the options interface table flow-set is inserted into the V9 export packet. The export packets are sent to the flow collector destination 10.1.1.1, where the source address is identical to the interface IP address of Loopback 0. The UDP destination port is 1024, and the DSCP value is 10:
RP/0/RP0/CPU0:router(config)# flow exporter-map fem1
RP/0/RP0/CPU0:router(config-fem)# destination 10.1.1.1
RP/0/RP0/CPU0:router(config-fem)# source Loopback 0
RP/0/RP0/CPU0:router(config-fem)# transport udp 1024
RP/0/RP0/CPU0:router(config-fem)# dscp 10
RP/0/RP0/CPU0:router(config-fem)# exit
RP/0/RP0/CPU0:router(config-fem)# version v9
RP/0/RP0/CPU0:router(config-fem-ver)# template data timeout 600
RP/0/RP0/CPU0:router(config-fem-ver)# options interface-table
RP/0/RP0/CPU0:router(config-fem-ver)# exit
|
Step 1 |
configure Example:Enters global configuration mode. |
||
|
Step 2 |
sampler-map map_name Example:Creates a sampler map and enters sampler map configuration mode. |
||
|
Step 3 |
random 1 out-of sampling_interval Example:Configures the sampling interval to use random mode for sampling packets. Replace the sampling_interval argument with a number, in the range from 1 through 65535 units.
|
||
|
Step 4 |
commit |
||
|
Step 5 |
exit Example:Exits sampler map configuration mode and enters the XR Config mode. |
||
|
Step 6 |
exit Example:Exits the mode and enters XR EXEC mode. |
||
|
Step 7 |
show sampler-map map_name Example:Displays sampler map data. |
RP/0/RP0/CPU0:router# sampler-map fsm1
RP/0/RP0/CPU0:router(config-sm)# random 1 out-of 65535
RP/0/RP0/CPU0:router(config)# exit
|
Step 1 |
configure Example:Enters global configuration mode. |
||||
|
Step 2 |
flow monitor-map map_name Example:Creates a monitor map and configures a monitor map name and enters flow monitor map configuration submode. |
||||
|
Step 3 |
Do one of the following:
Example:Configures the flow record map name for IPv4, IPv6, or MPLS.
|
||||
|
Step 4 |
cache entries number Example:(Optional) Configures the number of entries in the flow cache. Replace the number argument with the number of flow entries allowed in the flow cache, in the range from 4096 through 1000000. The default number of cache entries is 65535. |
||||
|
Step 5 |
cache permanent Example:(Optional) Disables removal of entries from flow cache. |
||||
|
Step 6 |
cache timeout {active timeout_value | inactive timeout_value | update timeout_value} Example:(Optional) Configures the active, inactive, or update flow cache timeout value.
|
||||
|
Step 7 |
exporter map_name Example:Associates an exporter map with a monitor map.
|
||||
|
Step 8 |
commit |
||||
|
Step 9 |
exit Example:Exits flow monitor map configuration submode. |
||||
|
Step 10 |
exit Example:Exits XR Config mode. |
||||
|
Step 11 |
show flow monitor-map map_name Example:Displays flow monitor map data. |
RP/0/RP0/CPU0:router(config)# flow monitor-map fmm1
RP/0/RP0/CPU0:router(config-fmm)# record ipv4
RP/0/RP0/CPU0:router(config-fmm)# exporter fem1
RP/0/RP0/CPU0:router(config-fmm)# cache entries 10000
RP/0/RP0/CPU0:router(config-fmm)# cache timeout active 30
RP/0/RP0/CPU0:router(config-fmm)# cache timeout inactive 15
RP/0/RP0/CPU0:router(config-fmm)# exit
|
Step 1 |
configure |
||
|
Step 2 |
interface type number Example:Enters interface configuration mode. |
||
|
Step 3 |
flow [ipv4 | ipv6 | mpls] monitor monitor_map sampler sampler_map {ingress} Example:
Enter ipv4 to enable IPV4 NetFlow on the specified interface. Enter ipv6 to enable IPV6 NetFlow on the specified interface. Enter mpls to enable MPLS-aware NetFlow on the specified interface. |
||
|
Step 4 |
commit |
RP/0/RP0/CPU0:router(config)#interface HundredGigE 0/3/0/0
RP/0/RP0/CPU0:router(config-if)#flow ipv4 monitor fmm1 sampler fsm1 ingress
RP/0/RP0/CPU0:router(config-if)#exit
RP/0/RP0/CPU0:router(config)#interface HundredGigE 0/3/0/0
RP/0/RP0/CPU0:router(config-if)# flow mpls monitor MPLS-IPv6-fmm sampler FSM ingress
RP/0/RP0/CPU0:router(config-if)#exit|
Step 1 |
configure |
||
|
Step 2 |
interface type number Example:Enters interface configuration mode. |
||
|
Step 3 |
flow [ipv4 | ipv6 | mpls] monitor monitor_map sampler sampler_map {ingress} Example:
Enter ipv4 to enable IPV4 NetFlow on the specified interface. Enter ipv6 to enable IPV6 NetFlow on the specified interface. Enter mpls to enable MPLS-aware NetFlow on the specified interface. |
||
|
Step 4 |
commit |
RP/0/RP0/CPU0:router(config)#interface bundle-ethernet 1
RP/0/RP0/CPU0:router(config-if)#flow ipv4 monitor fmm1 sampler fsm1 ingress
RP/0/RP0/CPU0:router(config-if)#exit
RP/0/RP0/CPU0:router(config)#interface bundle-ethernet 1
RP/0/RP0/CPU0:router(config-if)# flow mpls monitor MPLS-IPv6-fmm sampler FSM ingress
RP/0/RP0/CPU0:router(config-if)#exit|
Step 1 |
clear flow exporter [exporter_name] {restart | statistics} location node-id Example:Clears the flow exporter data. Specify the statistics option to clear exporter statistics. Specify the restart option to export all of the templates that are currently configured on the specified node. |
|
Step 2 |
clear flow monitor [monitor_name] cache [force-export | statistics] location node-id} Example:Clears the flow monitor data. Specify the statistics option to clear cache statistics. Specify the force-export option to export the data from cache to server first and then clear the entries from cache. |
The following example shows how to collect MPLS traffic with IPv4 payloads.
Router(config)#flow monitor-map MPLS-IPv4-fmm
Router(config-fmm)#record mpls IPv4-fields labels 3
Router(config-fmm)#cache permanent
Router(config-fmm)#exit
Router(config)#interface HundredGigE 0/3/0/0
Router(config-if)#flow mpls monitor MPLS-IPv4-fmm sampler fsm ingress
The following example shows how to collect MPLS traffic with IPv6 payloads.
Router(config)#flow monitor-map MPLS-IPv6-fmm
Router(config-fmm)# record mpls IPv6-fields labels 3
Router(config-fmm)#cache permanent
Router(config-fmm)#exit
Router(config)#interface HundredGigE 0/3/0/0
Router(config-if)#flow mpls monitor MPLS-IPv6-fmm sampler fsm ingress
The following example shows how to configure the NetFlow monitor to collect MPLS packets with IPv6 fields:
Router# config
Router(config)# flow exporter-map exp1
Router(config-fem)# version v9
Router(config-fem-ver)# options interface-table timeout 300
Router(config-fem-ver)# options sampler-table timeout 300
Router(config-fem-ver)# template data timeout 300
Router(config-fem-ver)# template options timeout 300
Router(config-fem-ver)# exit
Router(config-fem)# transport udp 12515
Router(config-fem)# source Loopback0
Router(config-fem)# destination 170.1.1.11
Router(config-fmm)# exit
Router(config)# flow monitor-map MPLS-IPv6-fmm
Router(config-fmm)# record mpls ipv6-fields labels 3
Router(config-fmm)# exporter exp1
Router(config-fmm)# cache entries 10000
Router(config-fmm)# cache permanent
Router(config-fmm)# exit
Router(config)# sampler-map FSM
Router(config-sm)# random 1 out-of 65535
Router(config-sm)# exit
Router(config)# interface HundredGigE 0/3/0/0
Router(config-if)# flow mpls monitor MPLS-IPv6-fmm sampler FSM ingress
The following example shows how to collect MPLS traffic with both IPv6 and IPv4 fields.
Router(config)# flow monitor-map MPLS-IPv4-IPv6-fmm
Router(config-fmm)# record mpls IPv4-IPv6-fields labels 3
Router(config-fmm)# cache permanent
Router(config-fmm)# exit
Router(config)# interface HundredGigE 0/3/0/0
Router(config-if)# flow mpls monitor MPLS-IPv4-IPv6-fmm sampler fsm ingress
Note |
Flow records are exported using the Version 9 format. |
/* This configuration collects MPLS traffic with IPv4 payloads. */
flow monitor-map MPLS-IPv4-fmm
record mpls IPv4-fields labels 3
cache permanent
exit
interface HundredGigE 0/3/0/0
flow mpls monitor MPLS-IPv4-fmm sampler fsm ingress
/* This configuration collects MPLS traffic with IPv6 payloads. */
flow monitor-map MPLS-IPv6-fmm
record mpls IPv6-fields labels 3
cache permanent
exit
interface HundredGigE 0/3/0/0
flow mpls monitor MPLS-IPv6-fmm sampler fsm ingress
/* This configuration collects MPLS packets with IPv6 fields */
flow exporter-map exp1
version v9
options interface-table timeout 300
options sampler-table timeout 300
template data timeout 300
template options timeout 300
exit
transport udp 12515
source Loopback0
destination 170.1.1.11
exit
flow monitor-map MPLS-IPv6-fmm
record mpls ipv6-fields labels 3
exporter exp1
cache entries 10000
cache permanent
exit
sampler-map FSM
random 1 out-of 65535
exit
interface HundredGigE 0/3/0/0
flow mpls monitor MPLS-IPv6-fmm sampler FSM ingress
/* This configuration collects MPLS traffic with both IPv6 and IPv4 fields */
flow monitor-map MPLS-IPv4-IPv6-fmm
record mpls IPv4-IPv6-fields labels 3
cache permanent
exit
interface HundredGigE 0/3/0/0
flow mpls monitor MPLS-IPv4-IPv6-fmm sampler fsm ingress
Verify the flow monitor map data.
Router# show flow monitor-map MPLS-IPv6-fmm
Flow Monitor Map : MPLS-IPv6-fmm
-------------------------------------------------
Id: 1
RecordMapName: ipv4-raw
ExportMapName: expmap-dtxr2
CacheAgingMode: Normal
CacheMaxEntries: 65535
CacheActiveTout: 60 seconds
CacheInactiveTout: 120 seconds
CacheUpdateTout: N/A
CacheRateLimit: 2000
Verify the exporter map data.
Router# show flow exporter-map expmap-dtxr2
Flow Exporter Map : expmap-dtxr2
-------------------------------------------------
Id : 1
DestinationIpAddr : 170.1.1.11
VRFName : default
SourceIfName : Loopback0
SourceIpAddr : 10.200.58.1
DSCP : 10
TransportProtocol : UDP
TransportDestPort : 12515
Export Version: 9
Common Template Timeout : 300 seconds
Options Template Timeout : 300 seconds
Data Template Timeout : 600 seconds
Interface-Table Export Timeout : 300 seconds
Sampler-Table Export Timeout : 0 seconds
VRF-Table Export Timeout : 0 seconds
Verify the netflow cache record for MPLS packet.
Router# show flow monitor MPLS-IPv6-fmm cache format record location 0/0/CPU0
Thu Feb 25 05:14:11.474 IST
Cache summary for Flow Monitor FNF_MONITOR_MAP_MPLS2:
Cache size: 256000
Current entries: 1
Flows added: 74
Flows not added: 0
Ager Polls: 4418
- Active timeout 73
- Inactive timeout 0
- Immediate 0
- TCP FIN flag 0
- Emergency aged 0
- Counter wrap aged 0
- Total 73
Periodic export:
- Counter wrap 0
- TCP FIN flag 0
Flows exported 73
========== Record number: 1 ==========
LabelType : BGP
Prefix/Length : ::/0
Label1-EXP-S : 0-0-0
Label2-EXP-S : 24026-0-1
Label3-EXP-S : -
Label4-EXP-S : -
Label5-EXP-S : -
Label6-EXP-S : -
InputInterface : BE100
OutputInterface : Hu0/0/0/3.1001
ForwardStatus : Fwd
FirstSwitched : 00 06:33:48:047
LastSwitched : 00 06:33:54:838
ByteCount : 1002010
PacketCount : 1033
Dir : Ing
SamplerID : 1
IPv6SrcAddr : 3001:10::2
IPv6DstAddr : 1001:10::2
IPv6TC : 0
IPv6FlowLabel : 7
IPv6OptHdrs : 0x10
IPV6Prot : 59
L4SrcPort : 0
L4DestPort : 0
L4TCPFlags : 0
InputVRFID : default
OutputVRFID : default
The following table lists supported drop codes on NetFlow, when a node is unable to forward the packets due to various reasons listed here. In such cases, the following drop codes are exported instead of output interface index.
|
Drop Reason(s) |
IPFIX/V9 Code |
|---|---|
|
Unknown |
128 |
|
ACL Deny |
129 |
|
Adjacency |
132 |
|
Bad Header Checksum |
134 |
|
Bad TTL |
137 |
These sections provide references related to interface configuration.
|
Related Topic |
Document Title |
|---|---|
|
Cisco IOS XR interface configuration commands |
Interface and Hardware Component Command Reference for Cisco NCS 5500 and NCS 540 and NCS 560 Series Routers |
|
Initial system bootup and configuration information for a router using the Cisco IOS XR software. |
|
|
Information about user groups and task IDs |
Interface and Hardware Component Command Reference for Cisco NCS 5500 and NCS 540 and NCS 560 Series Routers |
|
Information about configuring interfaces and other components from a remote Craft Works Interface (CWI) client management application. |
Cisco Craft Works Interface User Guide |
|
Standards |
Title |
|---|---|
|
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature. |
— |
|
MIBs |
MIBs Link |
|---|---|
| — |
Text for MIBs: To locate and download MIBs using Cisco IOS XR software, use the MIB Locator found at the Cisco Feature Navigator. |
|
RFCs |
Title |
|---|---|
|
3954 |
NetFlow services export protocol Version 9. |
|
7011 |
IPFIX protocol |
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