38. IPv6

• IPv4 uses 32 bits (about 4 billion addresses, 2³²)

• IPv6 uses 128-bit address (about 2⁵² addresses for every observable star in known universe.)

• Host identifier portion of IPv6 address uses 64 bits

  • (Note: MAC address is 48-bit long.)

• Most transport- and application-layer protocols need little or no change to operate over IPv6

• Actual address space utilization rates will likely be small in IPv6, but network management and routing will be more efficient.

• More: Wikipedia article IPv6