> > 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. +1 Steinar Haug, AS2116