On Feb 21, 2017, at 2:21 PM, Karsten Thomann
<karsten_thomann(_at_)linfre(_dot_)de> wrote:
Satisfies my desired outcome of the text, but I would like to modify it:
IPv6 unicast routing is based on prefixes of any valid length up to
128 [BCP198]. When using [SLAAC], [ILNP], or [NPT66] the Interface ID
of unicast addresses is required to be 64 bits long. An exception is for
example [RFC6164] which standardises 127 bit prefixes on point-to-point
links. The RECOMMENDED prefix length is 64 bit, but prefix lengths up to
128 bit can be possible on explicit configuration.
I’m reminded of when a vendor decided that /31 on ethernet was not a suitable
configuration and did not properly disclose in the release notes, causing a
subsequent series of outages.
I’m therefore cautious about the usage of any normative comment on bit mask
length.
Nothing quite like your interfaces losing their IP config after upgrade because
someone decided to more strictly interpret guidance.
- Jared