Addressing - Dell Force10 S4810P Configuration Manual

Addressing

IPv6 addresses are normally written as eight groups of four hexadecimal digits, where each group is
separated by a colon (:). For example, 2001:0db8:0000:0000:0000:0000:1428:57ab is a valid IPv6 address.
If one or more four-digit group(s) is 0000, the zeros may be omitted and replaced with two colons(::). For
example, 2001:0db8:0000:0000:0000:0000:1428:57ab can be shortened to 2001:0db8::1428:57ab. Only
one set of double colons is supported in a single address. Any number of consecutive 0000 groups may be
reduced to two colons, as long as there is
zeros in a group can also be omitted (as in ::1 for localhost, 1:: for network addresses and :: for unspecified
addresses).
All the addresses in the following list are all valid and equivalent.
• 2001:0db8:0000:0000:0000:0000:1428:57ab
• 2001:0db8:0000:0000:0000::1428:57ab
• 2001:0db8:0:0:0:0:1428:57ab
• 2001:0db8:0:0::1428:57ab
• 2001:0db8::1428:57ab
• 2001:db8::1428:57ab
IPv6 networks are written using Classless Inter-Domain Routing (CIDR) notation. An IPv6 network (or
subnet) is a contiguous group of IPv6 addresses the size of which must be a power of two; the initial bits of
addresses, which are identical for all hosts in the network, are called the network's prefix.
A network is denoted by the first address in the network and the size in bits of the prefix (in decimal),
separated with a slash. Since a single host is seen as a network with a 128-bit prefix, host addresses may be
written with a following /128.
For example, 2001:0db8:1234::/48 stands for the network with addresses
2001:0db8:1234:0000:0000:0000:0000:0000 through 2001:0db8:1234:ffff:ffff:ffff:ffff:ffff
Link-local Addresses
Link-local addresses, starting with
generated usually automatically by the operating system's IP layer for each network interface. This
provides instant automatic network connectivity for any IPv6 host and means that if several hosts connect
to a common hub or switch, they have an instant communication path via their link-local IPv6 address.
Link-local addresses cannot be routed to the public Internet.
Static and Dynamic Addressing
Static IPv6 addresses are manually assigned to a computer by an administrator. Dynamic IPv6 addresses
are assigned either randomly or by a server using Dynamic Host Configuration Protocol (DHCP). Even
though IPv6 addresses assigned using DHCP may stay the same for long periods of time, they can change.
In some cases, a network administrator may implement dynamically assigned static IPv6 addresses. In this
only one double colon used in an address
, are assigned only in the local link area. The addresses are
fe80:
. Leading and/or trailing
IPv6 Routing | 543