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+--- Thread: QID : AR433 - Prepend BGP (/thread-2911.html)
QID : AR433 - Prepend BGP - Solidus - 08-25-2026
It seems the right answer is to prepend the AS 200 and put the route-map on OUT, not IN.
Please fix it, maybe i'm wrong, but I think AS PREPEND is always used on OUT.
Any feedback would be great.
RE: QID : AR433 - Prepend BGP - jsqwe2 - 08-26-2026
The current answer is correct. The intent is to influence local decision making on your CE router, so by prepending the neighboring AS_PATH to incoming routes coming from that neighbor, it becomes less preferable.
Using as-path prepend OUT changes how your neighbors would see the routes you are advertising, making your AS_PATH longer / less preferable.
RE: QID : AR433 - Prepend BGP - Solidus - 08-26-2026
Thanks my dear. It's clear now. Basically in ISP's environnement we use to put local pref higher on IN and prepend OUT.
But for this question. It's all about prepend IN since we have the défault local pref and only one CE