On Tuesday, December 07, 2010 12:39:28 pm Les Mikesell wrote:
> > How many devices?  You mean exceeding the number of available inside a
> > IPv6 subnet?  I do hope you're kidding ... as for a /64 subnet we're
> > talking about 4.294.967.296 addresses doubled 32 times.
> 
> Is that what people will automatically get in a home ISP connection?

Abbreviations: PI = Provider Independent, PA = Provider Assigned, RIR = 
Regional Internet Registry, ARIN = American Registry of Internet Numbers, BGP = 
Border Gateway Protocol, AS = Autonomous System (the routing 'atom' at the BGP 
level), ASN = Autonomous System Number.

It will depend upon your provider if you get PA addresses; if you go straight 
to the RIR (ARIN for North America) and pay to get PI addresses you will get by 
default a /48; but then you have to get your provider to agree to advertise 
that /48 over BGP.  The IPv6 table has the potential to be vastly larger than 
the IPv4 table (the number of /48's in IPv6 is 65,536 times the total addresses 
in IPv4!)  One hopes providers will intelligently aggregate; until there is 
sane multihoming for enterprise endusers good aggregation is going to be 
elusive, since multihomed sites are going to desire PI space, which will 
fragment the routing tables.  IPv6 routing tables do require larger entries 
thanks to the four times larger address, after all, and with 32 bit ASN's the 
AS path for that table entry also doubles in size.

Having said that, most providers probably will give you one of a /48, /56, or 
/64.  There are plenty of addresses available, but if you ever have to renumber 
(like when changing providers).... you'll want PI, or ULA with NAT66 to PA.
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