M A G N U M 6 K S W I T C H E S , M N S - 6 K U S E R G U I D E
IPv6 Addressing
IPv6 addresses are 128-bits long and are identifiers for individual interfaces and sets of
interfaces. IPv6 addresses of all types are assigned to interfaces, not nodes. Since each
interface belongs to a single node, any of that node's interfaces' unicast addresses may be
used as an identifier for the node. A single interface may be assigned multiple IPv6
addresses of any type.
There are three types of
IPv6
addresses. These are unicast, anycast, and multicast. Unicast
addresses identify a single interface. Anycast addresses identify a set of interfaces such that
a packet sent to an anycast address will be delivered to one member of the set. Multicast
addresses identify a group of interfaces, such that a packet sent to a multicast address is
delivered to all of the interfaces in the group. There are no broadcast addresses in IPv6,
their function being superseded by multicast addresses.
IPv6
supports addresses which are four times the number of bits as IPv4 addresses (128
vs. 32). This is 4 Billion times 4 Billion times 4 Billion (2
96
) times the size of the IPv4
address space (2
32
). This works out to be:
340,282,366,920,938,463,463,374,607,431,768,211,456
This is an extremely large address space. In a theoretical sense this is approximately
665,570,793,348,866,943,898,599 addresses per square meter of the surface of the planet
Earth (assuming the earth surface is 511,263,971,197,990 square meters). In the most
pessimistic estimate this would provide 1,564 addresses for each square meter of the
surface of the planet Earth. The optimistic estimate would allow for
3,911,873,538,269,506,102 addresses for each square meter of the surface of the planet
Earth. Approximately fifteen percent of the address space is initially allocated. The
remaining 85% is reserved for future use.
The details on the addressing are covered by numerous articles on the WWW as well as
other literature and are not covered here.
Configuring IPv6
The commands used for IPv6 are the same as those used for IPv4. Some of the
commands will be discussed in more details later. The only exception is the
‘ping’
command where there is a special command for IPv6. That commands is
‘ping6’
and the
syntax is as
Syntax
ping6 <IPv6 address>
- pings an IPv6 station
There is also a special command to ping the status of IPv6. That command is
Syntax
show ipv6
- displays the IPv6 information
To configure IPv6, the following sequence of commands can be used.
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