On 128 bit addresses

From Steve Deering:

"""

Our experience looking at what the addressing plans that the OSI

community had come up with, they had specified this maximum of 20

and then they went out and designed plans that were exactly 20

bytes long.

So the nature was to basically provide lots of extra space in these

addresses and so I don't think we could have sort of kept short

addresses very long, the nature would be to just consume them and

make them longer.

"""

In practice, variable length addressing rapidly becomes maximum length addressing.