Syngress - Eleventh Hour Network+ Exam N10-004 Study Guide (11 ...

Understanding IP Addressing 91
IPv6: unicast, anycast, and multicast. Characteristics and benefits of IPv6
addresses are as follows:
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■
■
■
Expanded addressing moves us from 32-bit address to a 128-bit addressing
method.
IPv6 addresses are written as 32-hex digits, with colons (:) separating the
values of the eight 16-bit pieces of the address in hexadecimal format:
7060:0000:0000:0000:0006:0600:100D:315B
IPv6 virtually eliminates the need for address translation as a means of
accessing external networks due to aggregatable global unicast addresses
which do not require address translation, when used to access external
networks such as the Internet.
In IPv6, five header fields are eliminated. IPv6
packets have a fixed header of 40 bytes
in length.
UNDERSTANDING
IP ADDRESSING
Each IP address contains two elements: the
network address space or network ID and the
host address space or host ID.
TIP
For the Network+ exam, a firm
understanding of the development of
IPv6 and its differences over IPv4
(such as being able to identify an IPv6
address over an IPv4 address)
will be sufficient.
Fast Facts
Here are some key points related to converting from decimal to binary:
■ The binary system relies on only two digits: 0 and 1.
■ Each binary digit is called a bit, and in IP addressing, eight bits form an
octet.
■ Each octet has eight bits and a maximum value of 255.
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■
An IP address has four octets, or a total of 32 bits.
Binary numbers are counted beginning with bit 0, the right-most bit, as
shown in Table 6.1.
■ To create a binary number, we set the desired bit to 1.
■
To convert a binary number to decimal, add the value of each bit position
set to 1.
Table 6.1 Decimal Values
Bit number Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Decimal value 128 64 32 16 8 4 2 1