Re: Netflow Router-aggregate Mask option

Tharak
Thanks for the clarification. So basically the feature works as long as the
prefix-size < "netflow mask" in terms of prefix value?

Thanks

Tom

On Sun, Jan 16, 2011 at 7:27 PM, Abraham, Tharak <tharakabraham_at_gmail.com>wrote:

> 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
>>
>>
>> Blogs and organic groups at http://www.ccie.net
>>
>> _______________________________________________________________________
>> Subscription information may be found at:
>> http://www.groupstudy.com/list/CCIELab.html

Blogs and organic groups at http://www.ccie.net
Received on Tue Jan 18 2011 - 09:45:43 ART