Alternative to NetFlow for Measuring Traffic flows

Joe Abley jabley at isc.org
Tue Dec 17 03:37:30 UTC 2002


On Monday, Dec 16, 2002, at 22:28 Canada/Eastern, Richard A Steenbergen 
wrote:

> On Mon, Dec 16, 2002 at 09:16:55PM -0500, K. Scott Bethke wrote:
>>
>> based on ALL the ASN's of the people on the peering switch..  but in 
>> most
>> cases anyone pushing any real traffic will probably not have fine 
>> grained
>> samples enough to determine a peering relationship based on a  single 
>> AS
>> with this method.  Maybe Im wrong but hey if you are taking 200megs 
>> from any
>> one ASN I would hope you knew about it.
>
> Also, that method has the same "knowing the routes" problem as netflow.
> Whereever you are getting your list of ASN's route ASN.*"'s routes, 
> there
> is pretty much no way they are accurate (for an ASN of ANY size).
>
> You would have to statically route (or otherwise inject routes with a
> specific nexthop) a list of their customer prefixes that would have to 
> be
> manually transmitted.

If you are interested in traffic *to* a particular destination, surely 
you could just tweak localpref on routes based on an as-path filter?

If you are interested in traffic *from* a particular destination (you 
have a network full of eyes, not content) then this approach is not 
useful anyway.


Joe




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