Operation Manual

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 Leading zeros in each group can be removed. For example, the above-mentioned
address can be represented in shorter format as 2001:d02:0:0:14:0:0:95.
 Two colons (::) may be used to compress successive hexadecimal fields of zeros at the
beginning, middle, or end of an IPv6 address. For example, the above-mentioned
address can be represented in the shortest format as 2001:d02::14:0:0:95.
Note:
Two colons (::) can be used only once in an IPv6 address to represent the longest
successive hexadecimal fields of zeros. Otherwise, the device is unable to determine how
many zeros double-colons represent when converting them to zeros to restore a 128-bit
IPv6 address.
An IPv6 address consists of two parts: address prefix and interface ID. The address prefix
and the interface ID are respectively equivalent to the network ID and the host ID in an IPv4
address.
An IPv6 address prefix is represented in "IPv6 address/prefix length" format, where "IPv6
address" is an IPv6 address in any of the above-mentioned formats and "prefix length" is a
decimal number indicating how many leftmost bits from the preceding IPv6 address are
used as the address prefix.
2. IPv6 address classification
IPv6 addresses fall into three types: unicast address, multicast address, and anycast
address.
 Unicast address: An identifier for a single interface, on a single node. A packet that is
sent to a unicast address is delivered to the interface identified by that address.
 Multicast address: An identifier for a set of interfaces (typically belonging to different
nodes), similar to an IPv4 multicast address. A packet sent to a multicast address is
delivered to all interfaces identified by that address. There are no broadcast addresses
in IPv6. Their function is superseded by multicast addresses.
 Anycast address: An identifier for a set of interfaces (typically belonging to different
nodes). A packet sent to an anycast address is delivered to one of the interfaces
identified by that address (the nearest one, according to the routing protocols’ measure
of distance).
The type of an IPv6 address is designated by the first several bits called format prefix. The
following table lists the mappings between address types and format prefixes.