I have 3x IP Transits and 2x IXP connected to my router and absolutely we are paying more to IP Transits than IXP so I want to know what is the best local pref can I set for my outbound routes? my mean is local pref for received routes from IP Transits and IXP that act as outbound traffic for my users. i have set local pref 350 for both IXPs received routes and 250 for my IP transits received routes so in this case I force my users outbound traffic to my both IXP and if there is no routes in the IXP then they will use my IP Transits received routes, am I configured this correctly and logically ? thank you.
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The general rule is: you have complete control over traffic within your network, likewise everyone else has complete control of their network. You have total control over how traffic leaves your network, but effectively none on how it enters. If ISP A is the cheapest path for me, then that's where I'm going to force the traffic to go; your only choice is to not announce to ISP A. (if they're a transit provider, I can send it to them anyway.)– RickyJun 29, 2021 at 18:33
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Did any answer help you? if so, you should accept the answer so that the question does not keep popping up forever, looking for an answer. Alternatively, you could post and accept your own answer.– Ron Maupin ♦Dec 23, 2021 at 20:34
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Yes, that's a very common way to solve this.
answered Jun 29, 2021 at 7:28
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'tho prefs only control your route selection. They will have little ("no") effect on anyone else's selection. AS path length is the the primary selection criterion for BGP. A local admin can override that behavior. Short of community filter rules, outsiders cannot influence anything but AS path.– RickyJun 29, 2021 at 18:25