Configuring Aggregation Flow Caches

Aggregation caches are disabled by default. Exporting flow records from the router does not occur while it is in the disabled state. When the configuration for an aggregation cache is changed from enabled to disabled state, all flow records from that cache are removed and flow collection stops.

For Prefix, Destination Prefix, and Source Prefix aggregation caches, you can specify a minimum source and destination mask size to affect the granularity of the IP address space captured in the aggregation cache. The commands to configure the minimum mask size for the source and destination address are issued in Flow Cache Configuration mode and are specific to each aggregation cache:

The value (a number in the range 1–32) specifies the size of the minimum mask. The no version restores the default minimum mask size, which is 0. A mask of size N has the N most significant bits set in the corresponding bit mask.

You cannot configure a minimum mask size for aggregation caches that do not retain an IP address in their aggregation scheme (like the AS aggregation cache). You can configure the Prefix aggregation cache for both source and destination minimum mask size. You can configure only the source minimum mask size for the Source Prefix aggregation cache. You can configure only the destination minimum mask size for the Destination Prefix aggregation cache.

The peer/origin information configured with the export command for the man V5 cache is used to display the AS number of the AS aggregation cache for both the source and destination AS. If no (default) configuration is present, zero appears in the AS numbers for both V5 export and V8 export and in the show commands for the V8 AS aggregation cache.

Establish an aggregation cache:

1. Enter Flow Cache Configuration mode for the AS aggregation cache.

   host1(config)#ip flow-aggregation cache as

2. Configure the number of entries (1024—524288) in the aggregation cache; the no version sets the number of entries back to its default value of 4096 (flow-data may be lost if the previous setting is larger than the default).

   host1(config-flow-cache)#cache entries entryNumber

3. Set the active (1-60) and inactive (10-600) aging timers.

   host1(config-flow-cache)#cache timeout active active-tmo

   host1(config-flow-cache)#cache timeout inactive inactive-tmo

4. Configure an export destination for the aggregation cache; the no version removes the destination.

   host1(config-flow-cache)#export destination { hostname | ip address } udp-port-number

5. Set the source IP address for datagrams containing information from this cache: the no version removes the explicit setting of the source address.

   host1(config-flow-cache)#export source interfacetype interface

6. Enable the aggregation cache.

   host1(config-flow-cache)#enabled

   The aggregation cache starts accumulating information from the flow cache; the no version stops the accumulation of information from the flow cache, but does not suspend the operation of the flow cache.

cache entries

• Use to set the number of entries in the aggregation cache.
• Example

  host1(config-flow-cache)#cache entries 524288

• Use the no version to reset the number of entries to the default value 4096.
• See cache entries.

cache timeout

• Use to set the active and inactive timers.
• Example

  host1(config-flow-cache)#cache timeout active 50

• Use the no version to reset the default value.
• See cache timeout.

enabled

• Use to enable the aggregation cache to accumulate information form the flow cache.
• Example

  host1(config-flow-cache)#enabled

• Use the no version to stop the information flow from the flow cache.
• See enabled.

export destination

• Use to configure an export destination for the aggregation cache.
• Example

  host1(config-flow-cache)#export destination myhost udp-port

• Use the no version to remove the destination.
• See export destination.

export source

• Use to configure an export source for the aggregation cache.
• Example

  host1(config-flow-cache)#export source interface inf1

• Use the no version to remove the destination.
• See export source.

ip flow-aggregation cache

• Use to create an aggregation cache.
• Example

  host1(config)#ip flow-aggregation cache

• Use the no version to remove the aggregation cache and its configuration.
• See ip flow-aggregation cache.

mask destination

• Use to set the minimum mask size for the destination address for the prefix and destination prefix aggregation caches.
• Example

  host1(config-flow-cache)#mask destination 128

• Use the no version to restore the default mask size, which is 0.
• See mask destination.

mask source

• Use to set the minimum mask size for the source address for the prefix and source prefix aggregation caches.
• Example

  host1(config-flow-cache)#mask source 60

• Use the no version to restore the default mask size, which is 0.
• See mask source.

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