Dotted Decimal, IP Address and Doman Name Server
17:09
Converting
a 32-bit Internet
Address to Dotted Decimal
Format
An
Internet address, known as an IP address for “Internet Protocol”
is comprised of four binary octets, making it a 32-bit address. The
IP addresses are converted to “dotted decimal format” due to the
difficulty of humans to read in binary format. To convert the 32-bit
binary address to dotted decimal format, divide the address into four
8-bit octets and then convert each octet to a decimal number. Need to
remember that each octet will have one of 256 values (0 through 255).
As for the example 192.48.29.253.
Conversion
Method
Convert
the following 32-bit Internet address into dotted decimal format:
01011110000101001100001111011100
- Divide the IP address into four octets
01011110
00010100
11000011
11011100
- Convert each binary octet into a decimal number
01011110
= 64+16+8+4+2 = 94
00010100
= 16+4 = 20
11000011
= 128+64+2+1 = 195
11011100
= 128+64+16+8+4 = 220
- Write out the decimal values separated by periods
94.20.195.220
The
Internet Network layer
IP
Addressing: Introduction
IP
address:32-bit identifier for host, router interface. It is noted
that interface means connection between host, router and physical
link. Router’s typically have multiple interfaces while the host
may have multiple interfaces and also the IP addresses associated
with interface, not host, router.
IP
Address Classes
There
are 5 different classes of IP addresses which are A, B, C, D and E.
As for the A, B, and C, they are available for commercial use. For
example, a Class A network could support 126 networks, each with
16,777,216 hosts.
Subnet
Addressing
Classful
addressing inefficient which everyone want class B addresses. In
order to split class A, B addresses spaces and accommodate more
networks, it need another level of hierarchy. Defined by “subnet
mask”, which in general specifies the sets of bits belonging to the
network address and host address respectively.
The
Domain Name System
The
Domain Name System translates between domain names and IP addresses
of devices connected to the Internet. Part of Domain Name System is
domain name (a part of the URL) which is a unique alphanumeric name
such as gmu.edu. After that it has the top level domain name which is
edu and also the secondary level domain name which is gmu in the
above example (there could be up to 127 levels, but more than 4 is
rare)
Example
of top level domains :-
Generic
top level domains
- .com
- .biz
- .info
- .edu
- .mil
- .net, etc.
Country
codes (2 character codes)
- .jp, .sw, .us, etc.
Domain
Name Server (DNS)
- IP Addresses
Every
device connected has a unique 32-bit address. It also machine
readable e.g.151.196.19.22
- Domain Names
Every
device connected has an alphanumeric address. It also human readable
e.g. cnn.com
IP
address and domain name allocation requires central administration to
avoid duplication. Previously it was administered by U.S. government
contract (NSI). In 1998, technical coordination assigned to ICANN
(Internet Corporation for Assigned Names and Numbers).
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