Please pardon the crossposting between ppml and nanog... Geoff Huston <gih@apnic.net> writes:
Why /48 rather than /47 or /49? - alignment to nibble boundaries to make DNS delegation easier.
It has recently come to my attention that we are in error when we expect "n[iy]bble" to have the same amount of popular awareness as "byte". In point of fact, my guess is that most people who are not programmers (or particularly assembly language programmers) have minimal or no exposure to the term. Particularly in public policy discussions, such people abound, and their engagement in the process is no less important than that of a protocol implementer. Future proposals involving a preference toward doing things with 4-bit alignment should take care to explain what precisely a "n[iy]bble" is and hexadecimal numbering, and why it matters. ---Rob