[afripv6-discuss] IPv6 netmask on multi-access network segments

Warwick Duncan warwick at frogfoot.com
Mon Feb 10 11:27:16 SAST 2014

Hi Philip

On Sun, Feb 09, 2014 at 08:21:43PM +1000, Philip Smith wrote:
> Was there anything wrong with /127 for ptp links as recommended in
> http://www.rfc-editor.org/rfc/rfc6164.txt - most recent deployments I've
> seen use this (reserving the /64 for the subnet, but addressing it as a
> /127).

It was this paragraph from
http://bcop.nanog.org/images/6/62/BCOP-IPv6_Subnetting.pdf that led me
to prefer /126:

  Note well that there may be problems with using /127 prefix lengths in
  operation due to vendor implementation variance with regard to
  subnet-router anycast.  This issue is documented in RFC 3627,
  specifically in section 3.  Thorough testing in your own network
  environment is highly encouraged before attempting to use /127
  prefixes in production, particularly in multi-endor scenarios with any
  requirement for interoperability.

It seemed easier to just avoid possible problems right from the start.


Warwick Duncan
Frogfoot Networks ISP

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