No, it gives them 16 bits for subnetting. Everybody gets 64 bits for addressing because everybody (except oddballs and enevelope pushers) uses a /64 subnet size. Since 64 bits are more than anyone could ever possibly need for addressing and 16 bits is more than an end site could ever possibly need for subnetting, the /48 is an ideal allocation size.
As should be clear from the previous discussion, there are plenty of us who disagree here, and lean towards /56 for end users (typically residential customers) while business users would get a /48 or more based on need.
I wouldn't say that is a disagreement, more of an extension. In other words, many of us believe that 16 bits per end site is an ideal customer allocation, but feel that residential customers in their home are not in any way penalized by reducing this to 8 bits. They still have scope for a significant amount of subnetting even in extreme cases like constructing an inlaw suite plus operating a family business out of the home. I do agree that /56 per residential customer is the ideal allocation for a mid-sized to large ISP that has a large number of residential customer sites on its network. I expect that most such ISPs will implement a model with /48's to business and /56's to residential addresses. But I also expect that smaller ISPs or those who mainly supply business access services, will find it simpler to just give everyone a /48. The only place in which people have noted that there is a possibility of running out of bits in the existing IPv6 addressing hierarchy is when they look at a model where every residential customer gets a /48. In that scenario there is a possibility that we might runout in 50 to 100 years from now. If only the ISPs with a large residential user population go to a /56 per residential site, then we have solved the problem. --Michael Dillon