6.4. Configuring Cflowd with CLI

This section provides information to configure cflowd using the command line interface.

6.4.1. Cflowd Configuration Overview

SR OS implementation of cflowd supports the option to analyze traffic flow. The implementation also supports the use of traffic or access list (ACL) filters to limit the type of traffic that is analyzed.

6.4.1.1. Traffic Sampling

Traffic sampling does not examine all packets received by a router. Command parameters allow the rate at which traffic is sampled and sent for flow analysis to be modified. The default sampling rate is every 1000th packet. Excessive sampling over an extended period of time, for example, more than every 1000th packet, can burden router processing resources.

The following data is maintained for each individual flow in the raw flow cache:

Source IP address
Destinations IP address
Source port
Destination port
Forwarding status
Input interface
Output interface
IP protocol
TCP flags
First timestamp (of the first packet in the flow)
Last timestamp (timestamp of last packet in the flow prior to expiry of the flow)
Source AS number for peer and origin (taken from BGP)
Destination AS number for peer and origin (taken from BGP)
IP next hop
BGP next hop
ICMP type and code
IP version
Source prefix (from routing)
Destination prefix (from routing)
MPLS label stack from label 1 to 6

Within the raw flow cache, the following characteristics are used to identify an individual flow:

Ingress interface
Source IP address
Destination IP address
Source transport port number
Destination transport port number
IP protocol type
IP ToS byte
Virtual router ID
ICMP type and code
Direction
MPLS labels

SR OS implementation allows you to enable cflowd either at the interface level or as an action to a filter. By enabling cflowd at the interface level, all IP packets forwarded by the interface are subject to cflowd analysis. By setting cflowd as an action in a filter, only packets matching the specified filter are subject to cflowd analysis. This provides the network operator greater flexibility in the types of flows that are captured.

6.4.1.2. Collectors

A collector defines how data flows should be exported from the flow cache. A maximum of five collectors can be configured. Each collector is identified by a unique IP address and UDP port value. Each collector can only export traffic in one version type: V5, V8, V9, or V10.

The parameters within a collector configuration can be modified or the defaults retained.

The autonomous-system-type command defines whether the autonomous system information to be included in the flow data is based on the originating AS or external peer AS of the flow.

6.4.1.2.1. Aggregation

V8 aggregation allows for flow data to be aggregated into larger, less granular flows. Use aggregation commands to specify the type of data to be collected. These aggregation types are only applicable to flows being exported to a V8 collector.

The following aggregation schemes are supported:

AS matrix — Flows are aggregated based on source and destination AS and ingress and egress interface.
Protocol-port — Flows are aggregated based on the IP protocol, source port number, and destination port number.
Source prefix — Flows are aggregated based on source prefix and mask, source AS, and ingress interface.
Destination prefix — Flows are aggregated based on destination prefix and mask, destination AS, and egress interface.
Source-destination prefix — Flows are aggregated based on source prefix and mask, destination prefix and mask, source and destination AS, ingress interface and egress interface.
Raw — Flows are not aggregated and are sent to the collector in a V5 record.

6.4.2. Basic Cflowd Configuration

This section provides information to configure cflowd and examples of common configuration tasks. To sample traffic, the following parameters must be configured, as a minimum.

Cflowd must be enabled.
At least one collector must be configured and enabled.
Sampling must be enabled on either:
1. An IP filter entry (and applied to a service or a port).
2. An interface applied to a port.

The following example shows a cflowd configuration:

A:ALA-1>config>cflowd# info detail

----------------------------------------------

active-flow-timeout 1800

cache-size 65536

inactive-flow-timeout 15

overflow 1

rate 1000

collector 10.10.10.103:2055 version 9

no aggregation

autonomous-system-type origin

description "V9 collector"

no shutdown

exit

template-retransmit 330

exit

no shutdown

----------------------------------------------

A:ALA-1>config>cflowd#

6.4.3. Common Configuration Tasks

This section provides a brief overview of the tasks that must be performed to configure cflowd and provides the CLI commands. To begin traffic flow sampling, cflowd must be enabled and at least one collector must be configured.

6.4.3.1. Global Cflowd Components

The following common (global) attributes apply to all instances of cflowd:

Active flow timeout — Controls the maximum time a flow record can be active before it will be automatically exported to defined collectors.
Inactive flow timeout — Controls the minimum time before a flow is declared inactive. If no traffic is sampled for a flow for the inactive timeout duration, the flow is declared inactive and marked to be exported to the defined collectors.
Cache size — Defines the maximum size of the flow cache.
Overflow — Defines the percentage of flow records that are exported to all collectors if the flow cache size is exceeded.
Rate — Defines the system-wide sampling rate for cflowd.
Template retransmit— Defines the interval (in seconds) at which the V9 and V10 templates are retransmitted to all configured V9 or V10 collectors.

6.4.3.2. Enabling Cflowd

Cflowd is disabled by default. Cflowd is not shut down but must be configured, including at least one collector, to be active. Executing the cflowd command enables cflowd.

Use the following CLI syntax to enable cflowd:

CLI Syntax:

config# cflowd

no shutdown

The following example shows the default values when cflowd is initially enabled. No collectors or collector options are configured.

A:ALA-1>config# info detail

...

#------------------------------------------

echo "Cflowd Configuration"

#------------------------------------------

cflowd

active-flow-timeout 1800

cache-size 65536

inactive-flow-timeout 15

overflow 1

rate 1000

template-retransmit 600

no shutdown

exit

#------------------------------------------

A:ALA-1>config#

6.4.3.3. Configuring Global Cflowd Parameters

The following cflowd parameters apply to all instances where cflowd is enabled.

Use the following CLI commands to configure cflowd parameters:

CLI Syntax:

config>cflowd#

active-flow-timeout seconds

cache-size num-entries

enhanced-distribution

export-mode {automatic | manual}

inactive-flow-timeout seconds

overflow percent

rate sample-rate

template-retransmit seconds

no shutdown

The following example shows a sample cflowd configuration:

A:ALA-1>config>cflowd# info

#------------------------------------------

active-flow-timeout 1800

inactive-flow-timeout 10

overflow 10

rate 100

#------------------------------------------

A:ALA-1>config>cflowd#

6.4.3.4. Configuring Cflowd Collectors

To configure cflowd collector parameters, enter the following commands:

CLI Syntax:

config>cflowd#

collector ip-address[:port] [version version]

aggregation

as-matrix

destination-prefix

protocol-port

raw

source-destination-prefix

source-prefix

autonomous-system-type [origin | peer]

description description-string

no shutdown

template-set {basic | mpls-ip | l2-ip | mpls-transport}

The following example shows a basic cflowd configuration:

A:ALA-1>config>cflowd# info

-----------------------------------------

active-flow timeout 1800

inactive-flow-timeout 10

overflow 10

rate 100

collector 10.10.10.1:2000 version 8

aggregation

as-matrix

raw

exit

description "AS info collector"

exit

collector 10.10.10.2:5000 version 8

aggregation

protocol-port

source-destination-prefix

exit

autonomous-system-type peer

description "Neighbor collector"

exit

-----------------------------------------

A:ALA-1>config>cflowd#

Version 9 collector example:

collector 10.10.10.9:2000 version 9

description "v9collector"

template-set mpls-ip

no shutdown

exit

6.4.3.4.1. Version 9 and Version 10 Templates

If the collector is configured to use either V9 or V10 (IPFIX) formats, the flow data is sent to the designated collector using one of the predefined templates. The template used is based on the type of flow for which the data was collected (IPv4, IPv6, MPLS, or Ethernet (Layer 2)), and the configuration of the template-set parameter. Table 87 lists these values and the corresponding template used to export the flow data.

Table 87: Template Sets

Traffic Flow	Basic	MPLS-IP
IPv4	Basic IPv4	MPLS-IPv4
IPv6	Basic IPv6	MPLS-IPv6
MPLS	Basic MPLS	MPLS-IP
Ethernet	L2-IP	L2-IP

Each flow exported to a collector configured for either V9 or V10 formats will be sent using one of the flow template sets listed in Table 87.

Table 88 to Table 95 list the fields in each template listed in Table 87.

Table 88: Basic IPv4 Template

Field Name	Field ID
IPv4 Src Addr	8
IPv4 Dest Addr	12
IPv4 Nexthop	15
BGP Nexthop	18
Ingress Interface	10
Egress Interface	14
Packet Count	2
Byte Count	1
Start Time	22
End Time	21
Flow Start Milliseconds 1	152
Flow End Milliseconds 1	153
Src Port	7
Dest Port	11
Forwarding Status	89
TCP control Bits (Flags)	6
IPv4 Protocol	4
IPv4 ToS	5
IP version	60
ICMP Type & Code	32
Direction	61
BGP Source ASN	16
BGP Dest ASN	17
Source IPv4 Prefix Length	9
Dest IPv4 Prefix Length	13
Minimum IP Total Length	25
Maximum IP Total Length	26
Minimum TTL	52
Maximum TTL	53
Multicast Replication Factor	99
IsMulticast 1	206
Ingress VRFID 1	234
Egress VRFID 1	235

Note:

Only sent to collectors configured for V10 format.

Table 89: MPLS-IPv4 Template

Field Name	Field ID
IPv4 Src Addr	8
IPv4 Dest Addr	12
IPv4 Nexthop	15
BGP Nexthop	18
Ingress Interface	10
Egress Interface	14
Packet Count	2
Byte Count	1
Start Time	22
End Time	21
Flow Start Milliseconds 1	152
Flow End Milliseconds 1	153
Src Port	7
Dest Port	11
Forwarding Status	89
TCP control Bits (Flags)	6
IPv4 Protocol	4
IPv4 ToS	5
IP version	60
ICMP Type & Code	32
Direction	61
BGP Source ASN	16
BGP Dest ASN	17
Source IPv4 Prefix Length	9
Dest IPv4 Prefix Length	13
MPLS Top Label Type	46
MPLS Top Label IPv4 Addr	47
MPLS Label 1	70
MPLS Label 2	71
MPLS Label 3	72
MPLS Label 4	73
MPLS Label 5	74
MPLS Label 6	75
MPLS Label 7	76
MPLS Label 8	77
MPLS Label 9	78
MPLS Label 10	79
Minimum IP Total Length	25
Maximum IP Total Length	26
Minimum TTL	52
Maximum TTL	53
Multicast Replication Factor	99
IsMulticast 1	206
Ingress VRFID 1	234
Egress VRFID 1	235

Note:

Only sent to collectors configured for V10 format.

Table 90: Basic IPv6 Template

Field Name	Field ID
IPv6 Src Addr	27
IPv6 Dest Addr	28
IPv6 Nexthop	62
IPv6 BGP Nexthop	63
IPv4 Nexthop	15
IPv4 BGP Nexthop	18
Ingress Interface	10
Egress Interface	14
Packet Count	2
Byte Count	1
Start Time	22
End Time	21
Flow Start Milliseconds 1	152
Flow End Milliseconds 1	153
Src Port	7
Dest Port	11
Forwarding Status	89
TCP control Bits (Flags)	6
Protocol	4
IPv6 Extension Hdr	64
IPv6 Next Header	193
IPv6 Flow Label	31
ToS	5
IP version	60
IPv6 ICMP Type & Code	139
Direction	61
BGP Source ASN	16
BGP Dest ASN	17
IPv6 Src Mask	29
IPv6 Dest Mask	30
Minimum IP Total Length	25
Maximum IP Total Length	26
Minimum TTL	52
Maximum TTL	53
Multicast Replication Factor	99
IsMulticast 1	206
Ingress VRFID 1	234
Egress VRFID 1	235

Note:

Only sent to collectors configured for V10 format.

Table 91: MPLS-IPv6 Template

Field Name	Field ID
IPv6 Src Addr	27
IPv6 Dest Addr	28
IPv6 Nexthop	62
IPv6 BGP Nexthop	63
IPv4 Nexthop	15
IPv4 BGP Nexthop	18
Ingress Interface	10
Egress Interface	14
Packet Count	2
Byte Count	1
Start Time	22
End Time	21
Flow Start Milliseconds 1	152
Flow End Milliseconds 1	153
Src Port	7
Dest Port	11
Forwarding Status	89
TCP control Bits (Flags)	6
Protocol	4
IPv6 Extension Hdr	64
IPv6 Next Header	193
IPv6 Flow Label	31
ToS	5
IP version	60
IPv6 ICMP Type & Code	139
Direction	61
BGP Source ASN	16
BGP Dest ASN	17
IPv6 Src Mask	29
IPv6 Dest Mask	30
MPLS Top Label Type	46
MPLS Top Label IPv6 Addr	47
MPLS Label 1	70
MPLS Label 2	71
MPLS Label 3	72
MPLS Label 4	73
MPLS Label 5	74
MPLS Label 6	75
MPLS Label 7	76
MPLS Label 8	77
MPLS Label 9	78
MPLS Label 10	79
MPLS_TOP_LABEL_TYPE	46
MPLS_TOP_LABEL_ADDR	47
Minimum IP Total Length	25
Maximum IP Total Length	26
Minimum TTL	52
Maximum TTL	53
Multicast Replication Factor	99
IsMulticast 1	206
Ingress VRFID 1	234
Egress VRFID 1	235

Note:

Only sent to collectors configured for V10 format.

Table 92: Basic MPLS Template

Field Name	Field ID
Start Time	22
End Time	21
Flow Start Milliseconds 1	152
Flow End Milliseconds 1	153
Ingress Interface	10
Egress Interface	14
Packet Count	2
Byte Count	1
Direction	61
MPLS Top Label Type	46
MPLS Top Label Address	47
MPLS Label 1	70
MPLS Label 2	71
MPLS Label 3	72
MPLS Label 4	73
MPLS Label 5	74
MPLS Label 6	75

Note:

Only sent to collectors configured for V10 format.

Table 93: MPLS-IP Template

Field Name	Field ID
IPv4 Src Addr	8
IPv4 Dest Addr	12
IPv4 Nexthop	15
IPv6 Src Addr	27
IPv6 Dest Addr	28
IPv6 Nexthop	62
Ingress Interface	10
Egress Interface	14
Packet Count	2
Byte Count	1
Start Time	22
End Time	21
Flow Start Milliseconds 1	152
Flow End Milliseconds 1	153
Src Port	7
Dest Port	11
TCP control Bits (Flags)	6
IPv4 Protocol	4
IPv4 ToS	5
IP version	60
ICMP Type & Code	32
Direction	61
MPLS Top Label Type	46
MPLS Top Label IPv4 Addr	47
MPLS Label 1	70
MPLS Label 2	71
MPLS Label 3	72
MPLS Label 4	73
MPLS Label 5	74
MPLS Label 6	75
MPLS Label 7	76
MPLS Label 8	77
MPLS Label 9	78
MPLS Label 10	79

Note:

Only sent to collectors configured for V10 format.

Table 94: L2-IP (Ethernet) Flow Template

Field Name 1	Field ID
MAC Src Addr	56
MAC Dest Addr	80
Ingress Physical Interface	252
Egress Physical Interface	253
Dot1q VLAN ID	243
Dot1q Customer VLAN ID	245
Post Dot1q VLAN ID	254
Post Dot1q Customer VLAN Id	255
IPv4 Src Addr	8
IPv4 Dest Addr	12
IPv6 Src Addr	27
IPv6 Dest Addr	28
Packet Count	2
Byte Count	1
Flow Start Milliseconds	152
Flow End Milliseconds	153
Src Port	7
Dest Port	11
TCP control Bits (Flags)	6
Protocol	4
IPv6 Option Header	64
IPv6 Next Header	196
IPv6 Flow Label	31
ToS	5
IP Version	60
ICMP Type Code	32

Note:

Only one Ethernet (L2-IP) flow template is supported and exported to IPFIX (V10) collectors.

Table 95: MPLS TRANSPORT Template

Field Name	Field ID
Flow Start Milliseconds	152
Flow End Milliseconds	153
VRF ID	234
Ingress Interface	10
Packet Count	2
Byte Count	1
Direction	61
MPLS_TOP_LABEL_TYPE	46
MPLS_TOP_LABEL_ADDR	47
MPLS Label-1	70

Table 96: GRE Flow Template

Field Name 1	Field ID
IPv4 Src Addr 2	8
IPv4 Dest Addr 2	12
Ingress ID	252
Egress ID	253
Flow Start Milliseconds	152
Ingress VRF ID 2	234
Egress VRF ID 2	235
Protocol 2	4
ToS 2	5
Data Link Frame Size 3	312
Section Exported Octets 2	410
Data Link Frame Section 2	315

Notes:

The field names are exported only to IPFIX (V10) collectors.
The IP fields contain values from the outer GRE IP header.
The Data Link Frame section field includes the inner IP headers.

6.4.3.5. Specifying Cflowd Options on an IP Interface

When cflowd is enabled on an interface, all packets forwarded by the interface are subject to analysis according to the global cflowd configuration and sorted according to the collector configurations.

See Table 97 for configuration combinations.

When the cflowd-parameters sampling unicast type interface option is configured in the config>router>if context, the following requirements must be met to enable traffic sampling on the interface:

Cflowd must be enabled.
At least one cflowd collector must be configured and enabled.
The configure router interface cflowd-parameters sampling {unicast | multicast} type {acl |interface} [direction {ingress-only | egress-only | both}] command must be performed. By default, the direction is ingress-only.
To prevent certain types of traffic from being sampled when interface sampling is enabled, use the interface-disable-sample command in the config>filter>ip-filter or config>filter>ipv6-filter context. The filter must be applied to the service or network interface on which the traffic to be omitted is to ingress the system.

6.4.3.5.1. Interface Configurations

CLI Syntax:

config>router>if#

cflowd-parameters

sampling {unicast | multicast} type {acl | interface}

no sampling {unicast | multicast} type {acl|interface}

Depending on the option selected, either acl or interface, cflowd extracts traffic flow samples from an IP filter or an interface for analysis. All packets forwarded by the interface are analyzed according to the cflowd configuration.

The acl option must be selected to enable traffic sampling on an IP filter. Cflowd (filter-sample) must be enabled in at least one IP filter entry.

The interface option must be selected to enable traffic sampling on an interface. If cflowd is not enabled (no cflowd), traffic sampling will not occur on the interface.

6.4.3.5.2. Service Interfaces

CLI Syntax:

config>router>interface# cflowd-parameters sampling {unicast | multicast} type {acl | interface}

When enabled on a service interface, cflowd collects routed traffic flow samples through a router for analysis. Cflowd is supported on IES and VPRN services interfaces only. Layer 2 traffic is excluded. All packets forwarded by the interface are analyzed according to the cflowd configuration. On the interface level, cflowd can be associated with a filter (ACL) or an IP interface. L2 cflowd ingress sampling in supported on VPLS and Epipe SAPs.

6.4.3.6. Specifying Sampling Options in Filter Entries

Packets are matched against filter entries to determine acceptability. With cflowd, only the first packet of a flow is compared. If the first packet matches the filter criteria, an entry is added to the cflowd cache. Subsequent packets in the same flow are also sampled based on the cache entry.

Because a filter can be applied to more than one interface (when configured with a scope template), the interface-disable-sample option is intended to enable or disable traffic sampling on an interface-by-interface basis. The command can be enabled or disabled as needed instead of having to create numerous filter versions.

To enable an interface for filter traffic sampling, the following requirements must be met:

Cflowd must be enabled globally.
At least one cflowd collector must be configured and enabled.
On the IP interface being used, the configure router interface cflowd-parameters sampling {unicast | multicast} type acl option must be selected.
On the IP filter being used, the entry>filter-sample option must be explicitly enabled for the entries matching the traffic that should be sampled. The default is no filter-sample. See Filter Configuration for more information.
The filter must be applied to a service or a network interface. The service or port must be enabled and operational.

6.4.3.6.1. Filter Configurations

CLI Syntax:

config>filter>ip-filter>entry#

[no] filter-sample

[no] interface-disable-sample

CLI Syntax:

config>filter>ipv6-filter>entry#

[no] filter-sample

[no] interface-disable-sample

When a filter policy is applied to a service or a network interface, sampling can be configured so that traffic matching the associated IP filter entry is sampled when the IP interface is set to cflowd ACL mode and the filter-sample command is enabled. If cflowd is either not enabled (no filter-sample) or set to the cflowd interface mode, sampling does not occur.

When the interface-disable-sample command is enabled, traffic matching the associated IP filter entry is not sampled if the IP interface is set to cflowd ACL mode.

6.4.3.6.2. Dependencies

For cflowd to be operational, the following requirements must be met:

Cflowd must be enabled on a global level. If cflowd is disabled, any traffic sampling instances are also disabled.
At least one collector must be configured and enabled in order for traffic sampling to occur on an enabled entity.
If a specific collector UDP port is not identified, flows are sent to port 2055 by default.

Cflowd can also be dependent on the following entity configurations:

Interface Configurations
Service Interfaces
Filter Configurations

The combination of interface and filter entry configurations determines whether flow sampling occurs. Table 97 lists the expected results based on cflowd configuration dependencies.

Table 97: Cflowd Configuration Dependencies

Interface Setting	cflowd-parameter type Setting	Command ip-filter entry Setting	Expected Results
IP-filter mode	ACL	filter-sample	Traffic matching is sampled at specified rate
IP-filter mode	ACL	no filter-sample	No traffic is sampled on this interface
IP-filter mode or cflowd not enabled on interface	ACL	interface-disable-sample	Command is ignored; no sampling occurs
Interface mode	Interface	interface-disable-sample	Traffic matching this IP filter entry is not sampled
Interface mode	Interface	none	All IP traffic ingressing the interface is subject to sampling
Interface mode	Interface	filter-sample	Filter-level action is ignored; all traffic ingressing the interface is subject to sampling

6.5. Cflowd Configuration Management Tasks

This section describes Cflowd configuration management tasks:

6.5.1. Modifying Global Cflowd Components

Cflowd parameter modifications apply to all instances where cflowd is enabled. Changes are applied immediately. Use the following cflowd commands to modify global cflowd parameters:

CLI Syntax:

config>cflowd#

active-flow-timeout seconds

no active-flow-timeout

cache-size num-entries

no cache-size

[no] enhanced-distribution

export-mode {automatic | manual}

inactive-flow-timeout seconds

no inactive-flow-timeout

overflow percent

no overflow

rate sample-rate

no rate

[no] shutdown

template-retransmit seconds

no template-retransmit

The following example shows the cflowd command syntax to modify configuration parameters:

Example:

config>cflowd# active-flow-timeout 3600

config>cflowd# no inactive-flow-timeout

config>cflowd# overflow 2

config>cflowd# rate 10

The following example shows an example cflowd configuration:

A:ALA-1>config>cflowd# info

#------------------------------------------

active-flow-timeout 3600

overflow 2

rate 10

#------------------------------------------

A:ALA-1>config>cflowd#

6.5.2. Modifying Cflowd Collector Parameters

Use the following commands to modify cflowd collector and aggregation parameters:

CLI Syntax:

config>cflowd#

collector ip-address[:port] [version version]

no collector ip-address[:port]

[no] aggregation

[no] as-matrix

[no] destination-prefix

[no] protocol-port

[no] raw

[no] source-destination-prefix

[no] source-prefix

[no] autonomous-system-type [origin | peer]

[no] description description-string

[no] shutdown

template-set {basic | mpls-ip | l2-ip | mpls-transport}

If a specific collector UDP port is not identified, flows are sent to port 2055 by default.

The following example displays basic cflowd modifications:

A:ALA-1>config>cflowd# info

-----------------------------------------

active-flow-timeout 3600

overflow 2

rate 10

collector 10.10.10.1:2000 version 5

description "AS info collector"

exit

collector 10.10.10.2:5000 version 8

aggregation

source-prefix

raw

exit

description "Test collector"

exit

-----------------------------------------

A:ALA-1>config>cflowd#