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IPng (Internet Protocol next generation) IPv6 includes important changes to security handling, auto configuration,
efficiency of routing and handling of mobile users.
NO MORE BROADCASTS! In IPv6, broadcast is replaced
with a multicast.- thanks to new ScopeField. Nodes must announce that they
wish to receive multicast traffic bound for a particular broadcast address.
p584
IPv^Multicast address format:
|
8 |
4 |
4 |
112 bits |
| 11111111 |
FLAGS |
SCOPE |
GROUP ID |
IPV6 May be viewed as a string that uniquely identifies on single network
interface on the global Internet. Alternately, that address can
understood as an address with network and host portions. How much of
the address belongs to either portion depends on who's looking at it, where
they are located in relation to the host with that address.
Uses a colon as a separator, instead of the period
Has six groupings of numbers compared to four for IPv4 (128 bits long) (more
than 20 orders of magnitude over IPv4)
Each grouping is an eight bit number
The eight bits are made up of two, four-bit “nibbles”
Each group is a hexadecimal number between 0000 and FFFF
Leading zeros can be dropped from a group, so 00CF becomes simply CF
Use a pair of colons (::) to represent a string of consecutive 16-bit groups
with a value of zero
The unspecified address (all zeros) can never be used, nor can an address
that contains all ones
IPv6 offers an immense amount of additional IP addresses
Example: 1234:5678:90AB:CDEF:5555:6666
·
IPv6 addresses consist of eight octets of 4 hexadecimal numbers. These
numbers can have values ranging from 0000 to FFFF, and each set is delimited
by a colon (:). Just like IPv4 addresses, no IPv6 address may contain all
zeros or all F’s.
Nodes that need to tunnel IPv6 packets through IPv4 routers use the
IPv4-compatable address, called dual stack
nodes. They understand both IPc4 and IPv6. (IPv6 nodes that
need to communicate with IPv4 nodes that do not understand IPv6, all use the
IPv4-mapped address)
SCOPE IDENTIFIER: Multicast addresses use a 4-bit scope
identifier, which is a 4-bit field that limits the valid range for a
multicast address to define the portion of the Internet over which the
multicast group is valid. p581-2
INTERFACE IDENTIFIERS (RFC
3041): Follow the EUI-64 format. p581 following table
Global/local and individual/group bits in IPv6
| Bit 6 |
Bit 7 |
Meaning |
| 0 |
0 |
Locally unique, individual |
| 0 |
1 |
locally unique, group |
| 1 |
0 |
Globally unique, individual |
| 1 |
1 |
Globally unique, group |
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