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Re: Flow Tools AS-Path


From: Jörg Kost <jk () ip-clear de>
Date: Tue, 04 Apr 2023 17:13:33 +0200

Hi,

Extreme also supports it, and we use it for conducting statistics against dst_as/dst_peer_as to perform "traffic 
engineering" specifically for the transit paths. dst_as_path can also identify possible future peering situations or 
undesirable paths.

BR
Jörg

On 4 Apr 2023, at 16:48, Peter Phaal wrote:

Export of destination AS-Path is supported in the sFlow extended_gateway
structure.

/* Extended Gateway Data */
/* opaque = flow_data; enterprise = 0; format = 1003 */

struct extended_gateway {
   next_hop nexthop;           /* Address of the border router that should
                                  be used for the destination network */
   unsigned int as;            /* Autonomous system number of router */
   unsigned int src_as;        /* Autonomous system number of source */
   unsigned int src_peer_as;   /* Autonomous system number of source peer */
   as_path_type dst_as_path<>; /* Autonomous system path to the destination */
   unsigned int communities<>; /* Communities associated with this route */
   unsigned int localpref;     /* LocalPref associated with this route */
}

Arista EOS supports aspath if you enable sflow extension bgp. Cisco
also claims to support the feature on IOS XR platforms.

In addition to BGP, there are a number of MPLS, tunnel encap/decap
etc. sFlow extended structures.

Also optical interface metrics, dropped packet notifications, and more:

https://sflow.org/developers/specifications.php



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