HP-UX IPv6 Transport Administrator Guide HP-UX 11i v3 (5992-6426, May 2013)

4 IPv6 Addressing and Concepts
This chapter introduces network addressing concepts for IPv6. It contains sections on
Obtaining IPv6 Addresses, IPv6 Address Formats, Neighbor Discovery, Stateless Address
Autoconfiguration and some basic general Networking Terminology.
Where to Get IPv6 Addresses
To obtain an IPv6 address, contact a local ISP or the Regional Internet Registries from
the following list:
ARIN - American IPv6 registration services
APNIC- Asia Pacific Network Information Center
RIPE - European Regional Internet Registry
The amount of addresses allocated varies according to your network requirements. Small
Internet Service Providers (ISPs) or end nodes acquire IPv6 addresses from their upstream
provider. Large ISPs, for example can receive from ARIN a minimum prefix of /48 with
a second-level allocation of 16 bits for subnets. The remaining 64 bits are for a network
interface.
IPv6 Address Formats
IPv6 addresses are 128-bit entities. IPv4 addresses are 32-bit addresses normally written
as four decimal numbers (dotted decimal), one for each byte of the address.
Example: 192.1.2.34
IPv6 Node Addresses are 128-bit records represented as eight fields of up to four
hexadecimal digits. A colon separates each field (:). Example:
2001:db8:101::230:6eff:fe04:d9ff.
NOTE: The symbol “::” is a special syntax that can be used as a shorthand way of
representing multiple 16-bit groups of contiguous 0’s (zeros). The “::” can appear
anywhere in the address; however it can only appear once in the address.
To indicate a subnetwork address, IPv6 uses subnet prefixes similar to IPv4 CIDR format.
Figure 7shows a 128-bit IPv6 node address with a 64-bit subnet prefix.
Figure 7 IPv6 128-bit Addresses; HP-UX Default Prefix 64
An IPv6 node address and its subnet prefix length can be combined in the following
format:
<IPv6-Node-Address>/<Prefix-Length>
46 IPv6 Addressing and Concepts