IPv6 overview

Network Administration Guide for Hitachi NAS Platform

Part Number

The current Internet protocol address standard, IPv4, uses a 32-bit address and has an insufficient number of available addresses for global usage. The next generation Internet protocol address standard, IPv6, uses a 128-bit address. This provides a much larger pool of addresses. The NAS server supports both IPv4 and IPv6 at the same time (dual-stack).

Address formats

An IPv4 address consists of dotted quads, for example

For an IPv6 address, each 16 bits of the 128 bit address is represented as a hexadecimal number separated by a colon (:) as shown below:


Repeated fields of zeroes can be replaced by :: as shown below:

2001:db8::1:0:0:1 or 2001:db8:0:0:1::1 

There can only be one :: in the text representation of an address.

IPv6 addresses have a 64-bit netmask which consists of the 64 leftmost bits of the address which is represented in CIDR format as shown below:


This represents an address range of 2001:db8:0:0:0:0:0:0 to 2001:db8:0:0:ffff:ffff:ffff:ffff.

Address resolution

IPv6 uses NDP (Neighbor Discovery Protocol) instead of ARP for address resolution and IRDP for router discovery.