Yeah, cost to implement dst_as_path lookups far outweighs the usefulness IMO. If you really want that it's much better to get it via BMP. ( Same with communities and localpref in the extended gateway definition of sflow. ) Fundamentally I've always disagreed with how sFlow aggregates flow data with network state data. IMO you collect the two things separately, and join them off-device should you need to for analysis. On Thu, Mar 28, 2024 at 1:50 PM Saku Ytti <saku@ytti.fi> wrote:
Hey,
On Thu, 28 Mar 2024 at 17:49, Peter Phaal <peter.phaal@gmail.com> wrote:
sFlow was mentioned because I believe Brian's routers support the feature and may well export the as-path data directly via sFlow (I am not aware that it is a feature widely supported in vendor NetFlow/IPFIX implementations?).
Exporting AS information is wire-format agnostic feature, if it's supported or not, it can equally be injected into sFlow, NetflowV5 (src and dst only), NetflowV9 and IPFIX. The cost is that you need to program in FIB entries the information, so that the information becomes available at look-up time for record creation.
In OP's case (IOS-XR) this means enabling 'attribute-download' for BGP, and I believe IOS-XR will never download any other asn but src and dst, therefore full information cannot be injected into any emitted wire-format. -- ++ytti