لخّصلي

Internetworking connects heterogeneous networks (hardware and software) using routers, treating them like any other computer. The Internet Protocol (IP) software masks physical connection details and routing information. IP addresses provide a unified, 32-bit logical addressing method (2³² address space), written in dotted decimal or hexadecimal notation. IPv4 addresses comprise a network ID (prefix) and host ID (suffix); prefixes must be globally unique, as must suffixes within a network. Five IP address classes (A-E) exist, each with varying numbers of available networks and hosts, managed by IANA and RIRs. A subnet mask (e.g., 255.0.0.0 for Class A) identifies the network prefix via a bitwise AND operation with the IP address. A network address has a suffix of all zeros.

INTERNETWORKING
• Internetworking means providing universal service
among heterogeneous networks (hardware and
software).
• An internet (small i) is two or more networks connected
to each other.
• internets contain a few networks and the global Internet
contains tens of thousands of networks.
• Routers are used to connect heterogeneous networks.
• The network treats a connection to a router the same as
a connection to any other computer.
• Internet protocol software hides the details of physical
network connections, physical addresses, and routing
information.
INTERNETWORKING
IP ADDRESSES
The shape and length of physical addresses vary with
the type of network and manufacturing technology.
A unified addressing method must be used for all
networks.
The IP protocol provides a logical addressing method for
computers in the Internet.
Aunique address is given to each computer (IP address).
An IP address is a 32 bit unique address having an
address space of 232.
There are two notations in which IP address is written,
dotted
decimal notation and hexadecimal
notation
Dotted Decimal Notation
Hexadecimal Notation
IP ADDRESSES
 IPv4 address is divided into two parts:
 Prefix (Network ID)
 Suffix (Host ID)
No two networks can be given the same prefix and this
must be coordinated globally. Furthermore, two devices
in one network cannot be given the same suffix.
The five IP address classes are:
 Class A
 Class B
 Class C
 Class D
 Class E
CLASSES OF IP ADDRESSES
COMPUTING THE CLASS OF AN ADDRESS
o Maximum number of networks available in each class
and the maximum number of hosts per network.
o IP addresses are globally managed by Internet
Assigned Numbers Authority (IANA) and regional
Internet registries (RIR).
Example: class A has a total of:
27– 2= 126 network ID
224– 2 = 16,777,214 host ID
ADDRESSING EXAMPLE
SUBNET MASK (NETMASK)
 A subnet mask is a 32-bit number created by setting
host bits to all 0s and setting network bits to all 1s.
 When applied by a bitwise
AND operation to any IP
address in the network, yields the network prefix.
 Subnet masks are also expressed in
notation
like an IP address.
Class A: 255.0.0.0
Class B: 255.255.0.0
Class C: 255.255.255.0
dot-decimal
SPECIAL IP ADDRESSES
• NetworkAddress
When suffix contains all zeros