nested prefixes in Internet
niels=nanog at bakker.net
Mon Oct 10 17:24:45 UTC 2016
* r.engehausen at gmail.com (Roy) [Mon 10 Oct 2016, 19:19 CEST]:
>I don't think I ever said that ISP-B would announce the /19. That
>would only be announced by ISP-A. ISP-B would only announce the /24
>that has been delegated to it.
>If the ISP-A/ISP-B link goes down then the /24 would be seen only
>via ISP-C which is the desired result.
What if ISP-A then receives traffic inside its /19 destined for
ISP-B's /24? It will have to send it over transit and won't bill
ISP-B for that traffic. You cannot expect 100% of the rest of the
Internet to honour the more specific all the time.
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