From: Salvador Bertenbreiter <[email protected]>
Sent: Wednesday, January 7, 2026 5:54 PM
To: [email protected]
Subject: [routing-wg] Techniques to influence inbound (download) traffic across 
multiple IXPs with /24 prefixes

Hi everyone,

Hope you’re doing well. I’d like to ask how you approach inbound traffic 
engineering (download traffic) when you’re connected to multiple IXPs (some 
local, some remote) and you only have small prefixes (e.g., /24), so announcing 
more/less specifics isn’t really an option.

In that scenario, what methods have worked for you besides simple AS-path 
prepending (e.g., no prepend on local IX, prepend 1 on the closest remote IXP, 
prepend 2 on the next, etc.)?

Thanks in advance for any guidance or real-world examples.



Hi Salvador!

As Gert said: avoid “remote” peerings.

If you really need the remote peerings you probably want to connect to a 
specific peer. So do not peer with the IX route server but only peer bilateral 
with the important AS. (Or use the BGP communities of the IX route servers to 
“no-announce” or “prepend” your prefix selectively to certain peers”).

Regards
Klaus

[1] For example: AMS-IX Router Servers offer these communities: 
https://www.ams-ix.net/ams/documentation/ams-ix-route-servers
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