12

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 ?

19

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).

  • 1
    Wow, filtering on allocation length ? That makes impossible for a content provider to serve geo-based prefixes, right ? – Benjamin A. May 18 '13 at 11:19
  • 1
    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 May 18 '13 at 11:22
  • 1
    I should really subscribe to NANOG then, even if I'm french ! – Benjamin A. May 18 '13 at 11:28
  • It's as close to a global NOG as it gets, although posting non-North American content usually gets complaints. – LapTop006 May 18 '13 at 11:35
  • @BenjaminA.: This has been discussed on FRnOG too. See mail-archive.com/frnog@frnog.org/msg22235.html – petrus May 19 '13 at 9:31

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.