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Re: IPv6 Address Planning

  • From: Iljitsch van Beijnum
  • Date: Wed Aug 10 15:41:04 2005 
On 10-aug-2005, at 19:51, Daniel Senie wrote:


BTW, there is discussion about rethinking /48s for customers in IPv6.
Thoughts?



Where is this being discussed?



All over the place. IETF IPv6 wg, RIRs...




What sizing is being discussed?




The observation is that with the 80% HD ratio (= waste 1 bit in 5
because of administative boundaries in the addressing hierarchy) and
a /48 per customer we'll get awfully close to using up 128 bits
several decades from now. (3 bits are given for the global unicast
space, 80 for the customer = 45, 80% = 36 bits ~= 64 billion /48s for
some 10 billion people. Not immediately problematic, but a few more
bits margin just in case wouldn't be a bad idea.)



So we can change the HD ratio, change the /48 or change the /64. IETF
will 99% sure veto changing /64 because it's in a lot of RFCs and
implementations, so that leaves increasing the HD ratio or rethinking
giving _every_ customer a /48.




I'm expecting in the long run some ISPs will hand out /128s in the
hope that this will once and for all keep customers from putting
more than one device on a connection



That only makes sense if they can give out more /128s on demand for a
price to make more money. But I don't see it happening anyway.




(of course that would be followed immediately by implementations of
NATv6 if it happened).



Yeah right, the whole industry is going to spend man-years just
because one ISP does something weird? (Don't underestimate the crap
that goes on below the surface to make NAT work for stuff that isn't
simple TCP/client-server.)




There is a draft pending in the IETF V6OPS WG (draft-ietf-v6ops-
nap-01.txt) that relies heavily on the fact that everyone and his
dog gets a /48


A quick scan doesn't show this.