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In v4, most of the operators filter BGP updates for prefixes longer than a /24, to preserve the size of the full view.

What about IPv6 ? Is there such "convention" that stands out ?

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These days it's usually at /48, and it's very unlikely to ever be longer.

There are still AS' filtering longer than /32 though, but they should all have a default at this point (Verizon were a hold-out, but I believe they've given up).

There are also AS' filtering on allocation lengths, so if you got a /32 they might require you advertise it as such (based on the various RIR's documented allocation policies).

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    Wow, filtering on allocation length ? That makes impossible for a content provider to serve geo-based prefixes, right ? Commented May 18, 2013 at 11:19
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    Not really, if they're disparate networks the RIR's allow multiple allocations in the correct space (at least ARIN, RIPE & APNIC do). There was a recent NANOG thread about this.
    – LapTop006
    Commented May 18, 2013 at 11:22
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    I should really subscribe to NANOG then, even if I'm french ! Commented May 18, 2013 at 11:28
  • It's as close to a global NOG as it gets, although posting non-North American content usually gets complaints.
    – LapTop006
    Commented May 18, 2013 at 11:35
  • @BenjaminA.: This has been discussed on FRnOG too. See mail-archive.com/[email protected]/msg22235.html
    – petrus
    Commented May 19, 2013 at 9:31

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