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This feature module describes the NetFlow Minimum Prefix Mask for Router-Based Aggregation feature. It includes information on benefits of the new feature, supported platforms, supported standards, and the commands necessary to configure the NetFlow Minimum Mask for Router Aggregation feature.
This document includes the following sections:
To enable this feature for a particular aggregation cache, configure the desired minimum mask value using the NetFlow aggregation cache commands. The minimum mask value used by the router selects the granularity of the NetFlow data that will be collected:
The mask values range from 1 to 32.
The NetFlow Minimum Prefix Mask for Router Based Aggregation feature is only available with router-based aggregation. Minimum masking capability is available only if router-based aggregation is enabled. This feature is only available in the following three aggregation schemes:
This feature is not available in Automomous System (AS) aggregation and Protocol-port aggregation.
This feature is supported on the following platforms:
Standards
None
MIBs
No new MIBs are supported by this feature.
For descriptions of supported MIBs and how to use MIBs, see the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.
RFCs
None
Router-based aggregation must be enabled for minimum masking.
See the following sections for configuration tasks for the NetFlow Minimum Prefix Mask for Router-Based Aggregation feature. Each task in the list is identified as either optional or required:
To configure the minimum mask of a prefix aggregation scheme, use the following commands in aggregation cache configuration mode:
| Command | Purpose | |
|---|---|---|
Step 1 | Router(config)#ip flow-aggregation cache prefix | Configures the prefix aggregation cache. |
Step2 | Router(config-flow-cache)#mask source minimum value | Specifies minimum value for the source mask. |
Step3 | Router(config-flow-cache)#mask destination minimum value | Specifies minimum value for the destination mask. |
To configure the minimum mask of a destination-prefix aggregation scheme, use the following commands in aggregation cache configuration mode:
| Command | Purpose | |
|---|---|---|
Step1 | Router(config)#ip flow-aggregation cache destination-prefix | Configures the destination aggregation cache. |
Step2 | Router(config-flow-cache)#mask destination minimum value | Specifies minimum value for the destination mask. |
To configure the minimum mask of a source-prefix aggregation scheme, use the following commands in aggregation cache configuration mode:
| Command | Purpose | |
|---|---|---|
Step1 | Router(config)#ip flow-aggregation cache source-prefix | Configures the source-prefix aggregation cache. |
Step2 | Router(config-flow-cache)#mask source minimum value | Specifies minimum value for the source mask. |
To view the configured value of the minimum mask, use the show ip cache flow aggregation command for each aggregation scheme in EXEC mode:
| Command | Purpose |
|---|---|
Router#show ip cache flow aggregation prefix | Displays the configured value of the minimum mask in the prefix aggregation scheme. |
Router#show ip cache flow aggregation destination-prefix | Displays the configured value of the minimum mask in the destination-prefix aggregation scheme. |
Router#show ip cache flow aggregation source-prefix | Displays the configured value of the minimum mask in the source-prefix aggregation scheme. |
 |
NoteIf the minimum mask has not been explicitly configured, no minimum mask information is displayed. The default value of the minimum mask is zero. The configurable range for the minimum mask is from 1 to 32. An appropriate value should be chosen by the user depending on the traffic. A higher value of the minimum mask will provide more detailed network addresses, but it may also result in increased number of flows in the aggregation cache. |
This section provides the following configuration examples:
! ip flow-aggregation cache prefix mask source minimum 24 mask destination minimum 28
! ip flow-aggregation cache destination-prefix mask destination minimum 32 !
ip flow-aggregation cache source-prefix mask source minimum 30 !
This section documents modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.1 command reference publications.
To enable aggregation cache configuration mode, use the ip flow-aggregation cache global configuration command.
To disable aggregation cache configuration mode, use the no form of this command.
ip flow-aggregation cache {as | destination-prefix | prefix| protocol-port | source-prefix}
Syntax Description
as Configures the autonomous system aggregation cache scheme. destination-prefix Configures the destination prefix aggregation cache scheme. prefix Configures the prefix aggregation cache scheme. protocol-port Configures the protocol port aggregation cache scheme. source-prefix Configures the source prefix aggregation cache scheme.
Defaults
This command is not enabled by default.
Command Modes
Global configuration
Command History
12.0(3)T This command was introduced.
Release
Modification
Usage Guidelines
In the source-prefix aggregation mode, only the source mask is configurable. In the destination-prefix aggregation mode, only the destination mask is configurable.
Examples
The following example shows how to enable an autonomous system aggregation scheme:
ip flow-aggregation cache as enable
Related Commands
mask destination Specifies the destination mask. mask source Specifies the source mask. show ip cache flow aggregation Displays the aggregation cache configuration.
Command
Description
To specify the destination mask, use the mask destination destination-prefix aggregation cache configuration command. To disable the destination mask, use the no form of this command.
mask destination minimum value
Syntax Description
minimum Configures the minimum value for the mask. value Specifies the value for the mask. Range is from 1 to 32.
Defaults
0
Command Modes
Destination-prefix aggregation cache
Command History
12.1(2)T This command was introduced.
Release
Modification
Usage Guidelines
This command is only available with router-based aggregation. Minimum masking capability is not available if router-based aggregation is not enabled.
Examples
The following example shows how to configure the destination-prefix aggregation cache with a minimum mask value:
ip flow-aggregation cache destination-prefix mask destination minimum 32
Related Commands
ip flow-aggregation cache Enables aggregation cache configuration mode. mask source Specifies the source mask. show ip cache flow aggregation Displays the aggregation cache configuration.
Command
Description
To specify the source mask, use the mask source source-prefix aggregation cache configuration command. To disable the source mask, use the no form of this command.
mask source minimum value
Syntax Description
minimum Configures the minimum value for the mask. value Specifies the value for the mask. Range is from 1 to 32.
Defaults
0
Command Modes
Source-prefix aggregation cache
Command History
12.1(2)T This command was introduced.
Release
Modification
Usage Guidelines
This command is only available with router-based aggregation. Minimum masking capability is not available if router-based aggregation is not enabled.
Examples
The following example shows how to configure the source-prefix aggregation cache with a minimum mask value:
ip flow-aggregation cache source-prefix mask source minimum 30
Related Commands
ip flow-aggregation cache Enables aggregation cache configuration mode. mask destination Specifies the destination mask. show ip cache flow aggregation Displays the aggregation cache configuration.
Command
Description
To display the aggregation cache configuration, use the show ip cache flow aggregation command in EXEC mode.
show ip cache flow aggregation type
Syntax Description
type Displays the configuration of a particular aggregation cache:
Defaults
No default behavior or values.
Command Modes
EXEC
Command History
12.0(3)T This command was introduced.
Release
Modification
Examples
The following is an example display of an autonomous system aggregation cache using the showipcache flow aggregation as command:
show ip cache flow aggregation as IP Flow Switching Cache, 278544 bytes 2 active, 4094 inactive, 13 added 178 ager polls, 0 flow alloc failures Src If Src AS Dst If Dst AS Flows Pkts B/Pk Active Fa1/0 0 Null 0 1 2 49 10.2 Fa1/0 0 Se2/0 20 1 5 100 0.0
Table 1 describes the fields shown in this example.
| Field | Description |
|---|---|
Src If | Specifies the source interface. |
Src AS | Specifies the source autonomous system. |
Dst If | Specifies the destination interface. |
Dst AS | Specifies the destination autonomous system. |
Flows | Number of flows. |
Pkts | Number of packets. |
B/Pk | Average number of bytes observed for the packets seen for this protocol (total bytes for this protocol or the total number of flows for this protocol for this summary period). |
Active | Number of active flows in the NetFlow cache at the time this command was entered. |
Related Commands
ip flow-aggregation cache Enables aggregation cache configuration mode.
Command
Description
Posted: Sun Jun 11 21:50:22 PDT 2000
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