Gert,
Michel Py wrote: available for that. What Gert wants is a large number of bits to make the subnet number look good, in the *subnet* bits,
Gert Doering wrote: Call it "look good", but at least you understand the goal. I appreciate that.
Don't get me wrong: the goal (like any naming convention) is good (although operational experience suggests that in this very case it will be useless after a few years). This is not the point. The point is that you think that you can use the IID bits for routing purposes. This discussion has come five times on the table in the last 10 years and has always ended in the hole. In a nutshell, what you want is to declare that the IID bits could have a mixed use, either as IID bits or as subnet bits. Sharing the IID bits for routing purposes is not a good idea, and we just don't have enough bits to do what you want otherwise.
At least four people have voiced here that they are doing this, and I'm pretty sure that many more networks are doing non-/64s on point-to-point links for similar or other reasons)
As Randy and I said before, the ipv6 WG would be the place to discuss addressing architecture issues. I will clue you though that what some call the "old guard" includes lots of very knowledgeable people with CONSIDERABLE operational experience, including a number of people that have tried what you suggest before with other protocols. Large address spaces such as IPv6 are nothing new to some of us. More than a decade ago, I was dealing with a lot of Novell/IPX networks. The IPX address is 80 bits, 48 IID bits and 32 subnet bits (Hex notation same as IPv6). We did see a lot of funny subnets numbers such as "BABE4B0B" and a few other more explicit ones that I can't really mention here. They were contests to name subnets in the good old IPX days. Anyway, at the time these 32 subnet bits were more than enough to do what you are suggesting for IPv6, some people including myself actually tried, and after reorganizing and merging networks it becomes meaningless. In short: Nice idea, bit a) it does not work in the long run, we tried it before and b) even if it did the benefits that it brings are not worth running the IID bits in mixed mode anyway. Michel.