IPv6 addressing

IPv6 addressing is not the same as IPv4. Here are some notes about the situation.


 * Short version:
 * 2000::/3 – The currently active global unicast pool
 * RIRx::/12 – IANA (by default) assigns /12s to RIRs
 * RIRx:ISPx::/32 – RIRs (by default) assign /32s to ISPs
 * RIRx:ISPx:ORGx::/48 – ISPs (by default) assign /48s to enterprises
 * RIRx:ISPx:ORGx::/56s – Assigned to home (small) customers
 * RIRx:ISPx:ORGx:VLAN::/64 – Enterprises 'subnet' their allocation into
 * RIRx:ISPx:ORGx:LINK::/64s – P2P links (debate over [/126 | /127] to P2P links)

The essential initial guidelines are:


 * ISP – /32
 * Enough for 4billion ISPs
 * Enough for each ISP to support 65,536 /48 customers or 16.7M /56 customers, etc.
 * Larger ISPs can get more than a /32 if needed.


 * End Site – /48
 * Enough for 65,536 /64 subnets
 * Larger organizations can get more than a /48 if needed.


 * Single Subnet – /64
 * Enough for more hosts than ethernet MACs in a single subnet (ethernet MAC is 48 bits).
 * Support for 64 bit MAC addresses
 * Support for stateless autoconfiguration (EUI-64)