PROPOSED:
IPv6 unicast routing is based on prefixes of any valid length up to
128 [BCP198]. For example, [RFC6164] standardises 127 bit prefixes
on inter-router point-to-point links. However, the Interface ID of
unicast addresses used for Stateless Address Autoconfiguration
[RFC4862] is required to be 64 bits long. The rationale for the 64
bit boundary in IPv6 addresses can be found in [RFC7421]
i can live with this.
randy