Topic 10: Network & Communication Fundamentals IP ADDRESSING

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24 Οκτ 2013 (πριν από 3 χρόνια και 7 μήνες)

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Topic 10:

Network & Communication
Fundamentals


IP ADDRESSING


Lecture Objectives


Name the addressing scheme widely used
at network layer;


State five IPv4 classes;


State techniques to overcome the
shortcoming of classful IPv4 addresses;


Identify the IP address and sub netting for
Class C network; and


List several reserved IPv4 addresses.

Introduction


The most common Internet address
assignment scheme in use today
-
IPv4
provides the bank of routing addresses
based on the size of the organisation.


This is referred to as
classful

IP
addressing.


Three variants of
classful

addressing are
in common use today: Class A for
extremely

large organisations
, Class B for
large organisations
, and Class C for
smaller organisations

IP Network Class


THE REVOLUTION OF TELECOMMUNICATIONS

INFRASTRUCTURE


Every machine on the Internet has a
unique identifying number, called an
IPv4

address. A typical IPv4 address looks like
this:
216.27.61.137


In binary,

11011000.00011011.00111101.10001001

-
The four numbers in an IPv4 address are
called
octets


the total number of possible combinations
per octet is
28

or
256
.

Reserved IPs


IPv4 address 0.0.0.0 is reserved for the
default network

and the address
255.255.255.255 is used for
broadcasts


The octets are split into two sections:


Net (The Net section always contains the first
octet) is used to identify the network that a
computer belongs to.


Host (or Node) identifies the actual computer
on the network


The host section always contains the last
octet. There are
five IPv4
classes plus
certain special addresses:

Class A network


In Class A networks, the high order bit
value (the very first binary number) in the
first octet is always
0
. Example as follows:





Loopback

-

The IPv4 address 127.0.0.1 is
used as the loopback address. This
means that it is used by the host computer
to send a message back to itself.


-

It is commonly used for troubleshooting
and network testing.

Class B Network


Class B
-

Class B is used for
medium
-
sized networks.


A good example is a large college
campus.


IPv4 addresses with a first octet from 128
to 191 are part of this class.


Class B addresses also includes the
second octet as part of the Net identifier.


Valid Host IP addresses range from
128.1.0.1
-
191.255.255.254
.


The other two octets are used to identify
each host.

Class C Network


Class C
-

Class C addresses are
commonly used for small to mid
-
size
businesses.


IPv4 addresses with a first octet from 192
to 223 are part of this class.


Class C addresses also include the
second and third octets as part of the Net
identifier.
The last octet is used to identify
each host
.


Valid Host IP addresses range from
192.0.1.1
-
223.255.255.254.

IP Address service


Currently, there are two types of Internet
Protocol (IP) addresses in active use:
IP
version 4 (IPv4)

and
IP version 6 (IPv6).


Both IPv4 and IPv6 addresses are
assigned in a delegated manner. Users
are assigned IP addresses by
Internet
service providers

(ISPs). ISPs obtain
allocations of IP addresses from a
local
Internet registry

(LIR) or national Internet
registry (NIR), or from their appropriate
regional Internet registry (RIR)
as follows:

IP Address service


Both IPv4 and IPv6 addresses are
assigned in a delegated manner. Users
are assigned IP addresses by Internet
service providers (ISPs).


ISPs obtain allocations of IP addresses
from a local Internet registry (LIR) or
national Internet registry (NIR), or from
their appropriate regional Internet registry
(RIR) as follows:

CASE STUDY: IP ASSIGNMENT AND

SUBNETTING FOR CLASS C NETWORK

What is
subnetting
?


Subnetting

is the process of borrowing bits
from the HOST bits, in order to divide the
larger network into small subnets.


Subnetting

does
NOT

give you more
hosts, but actually costs you hosts.

Subnetting


subnetting is one of the techniques used
to overcome the shortage of Classful IPv4
addresses.


Other schemes used are Private
addressing with NAT/PAT, Supernetting
and IPv6.

Before calculating subnet…

TRUTH TABLE…


Logic Gates

Logic Gates

Scenario

An academic institution has acquired a Class C
address 192.168.1.0 from the local TELCO. The
company needs to create subnets to provide low
level security and broadcast control on the LAN.
The LAN consists of the following, each of which
will require its own subnet:


1.

Classroom #1
28 nodes

2.

Classroom #2
22 nodes

3.

Computer lab
30 nodes

4.

Instructor
12 nodes

5.

Administration
8 nodes

Questions to ask:

(a) How many subnets are needed for this
network?

(b) What is the subnet mask for this
network?

(i) Dotted decimal

(ii) Binary

(iii) Slash format

(c) How many usable hosts are there per
subnet?

Complete the table


Questions

(e) What is the host range for subnet six?

(f) What is the broadcast address for the 3rd
subnet?

(g) What is the broadcast address for the major
network?

(h) Is 192.168.1.32 a usable IP address?

(i) What is the first usable address in the 3rd
subnet?

(j) What is the last address for the 4th subnet?

(k) Are 192.168.1.45 and 192.168.1.65 in the same
subnet?

THE END