Gert,

Gert Doering wrote: Hummm? You're a bit confused about left and right?

Doh!

But this is what IPv6 is all about, isn't it? Give people a big enough address space so that they can do things the *easy* way, instead of the conservative way. Allocate sparsely, and make use of the address space.

Yes, but to a reasonable extent. Following your logic, you will soon need 16 more bits to accommodate 32-bit ASNs, then it would also be nice to have some bits to say if the customer's router a Cisco or a Juniper or Linux, some other bits so match the link type, and speed, and so on. It never ends, because each network has specific needs. I hear what you say; it would be elegant just by looking at the prefix to be able to tell something about it. In the end though, it does not replace network documentation which is paramount for operations. When I troubleshoot a route, I will lookup in the database anyway to see where it goes, over what kind of link, etc. There's stuff you can't put in the address, such as billing. Example: the customer calls the NOC whining being down. He's down because he has not paid. Yes, you could put in the interface description that it was shutdown by Joe because of billing issues, but I'd rather have the telco CktID there. If your NOC tech does a no shut without looking up the database and customer info, you're wasting money because someone else will waste more time shutting it down another time. This is all about good operational practices: if your documentation and change management are good, you don't need that kind of trick. You want to know what a prefix is about? Lookup the database, it will tell you what you need and possibly things you might not have thought about, such as billing.

My numbering plan requires AS number, router ID and link number in the network part for each point-to-point link.

This is what is flawed, IMHO. You basically say that you want 48 bits out of the address space just to have subnet numbers that look neat. If the IPv6 address was 256 bits that would have been possible but not with 128 bits. Michel.