Re: Netflow Router-aggregate Mask option

Tom,
Minimum doesn't mean that you will cut down the mask to a lower value.
Its actually means "atleast" in the aggregate context.

So actually when summary routes increases this feature maintains a
granularity for the prefixes.
In your case you will still have the /24, as same as your prefix

Tharak Abraham Luke

On Sun, Jan 16, 2011 at 11:23 PM, Tom Kacprzynski <tom.kac_at_gmail.com> wrote:

> Hello
> I am a little bit confused about the mask feature in netflow
> router-aggregate. I was under the impression that when you configure the
> minimal mask that it would aggregate for a prefix length that's smaller or
> larger then the routing table's prefix. For example:
>
> I have a few routes that are /16:
>
> Rack1R4#sh ip route 30.0.0.0 255.0.0.0 longer-prefixes
> 30.0.0.0/16 is subnetted, 4 subnets
> R 30.2.0.0 [120/1] via 204.12.1.254, 00:00:02, GigabitEthernet0/0
> R 30.3.0.0 [120/1] via 204.12.1.254, 00:00:02, GigabitEthernet0/0
> R 30.0.0.0 [120/1] via 204.12.1.254, 00:00:02, GigabitEthernet0/0
> R 30.1.0.0 [120/1] via 204.12.1.254, 00:00:02, GigabitEthernet0/0
>
> I would like to configure netflow to aggregate based on a destination
> prefix mask of /8, so I configure the router:
>
> ip flow-aggregation cache destination-prefix
> mask destination minimum 8
> enabled
>
> I ping few of the hosts in the 30.x.x.x subnet and this is what aggregation
> I get:
>
> Rack1R4#sh ip cache verbose flow aggregation destination-prefix
> ...
> Minimum destination mask is configured to /8
>
> Dst If Dst Prefix Msk AS Flows Pkts B/Pk Active
> Gi0/1 155.1.146.0 /24 0 1 5 100 0.0
> Gi0/0 30.1.0.0 * /16* 0 3 15 100 23.2
> Gi0/0 30.2.0.0 * /16* 0 1 5 100 0.0
>
> ...as you can see it's NOT aggregating it to the /8 as I set it in the
> aggregation cache with minimal destination mask but it's still using the
> /16 as it's in the routing table.
>
> Anyway to configure this with aggregate for /8?
>
> Thank you in advance for any help.
>
> TK
>
>
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Received on Mon Jan 17 2011 - 06:57:01 ART