2. OSI Model
• The OSI (Open Systems Interconnection) model is a
layered framework for the design of network
systems that allows communication between all
types of computer systems.
• It consists of seven separate but related layers.
• Each layer defines a part of the process of moving
information across a network.
• An OSI model provides a solid basis for
understanding data communications.
Introduction to TCP/IP
3. Layered Architecture
• .
• Each layer performs unique and
specific task and it offers services
to the layer above it.
• For example, Layer 3 uses the
services provided by layer 2 and
provides services for layer 4.
Introduction to TCP/IP
4. TCP/IP MODEL
• The Internet Protocol Suite (commonly known as TCP/IP)
is the set of communications protocols used for the
Internet and other similar networks.
• It is named from two of the most important protocols in it:
• The Transmission Control Protocol (TCP) and
• The Internet Protocol (IP), which were the first two networking
protocols defined in this standard
Introduction to TCP/IP
5. The Transport Layer
Introduction to TCP/IP
• This layer acts as the delivery service used by
the application layer.
• The two protocols used are TCP and UDP.
• The choice is made based on the application's
transmission reliability requirements.
• The transport layer also handles all error
detection and recovery.
6. The Transport Layer
Introduction to TCP/IP
• The Transport Layer is responsible not only for application
addressing, but also for providing reliable communications
over the best effort Layer 3 protocols.
• The Transport Layer provides:
• Flow control
• Windowing
• Data sequencing
• Recovery
7. Multiplexing Using TCP Port
Numbers
Introduction to TCP/IP
Multiplexing relies on the use of a
concept called a socket. A socket
consists of three things:
An IP address
A transport protocol
A port number
8. The Network Layer
Introduction to TCP/IP
• Provides services to exchange packets over the
network between identified end devices
• To accomplish this end-to-end Transport, Network
Layers uses 4 basic processes:
• Addressing
• Encapsulation
• Routing
• De-encapsulation
Segment
Packet
Frame
10. The Data-Link Layer
Introduction to TCP/IP
• Handles the moving of data into and out of a
physical link in a network.
• It ensures that the pace of the data flow
doesn’t overwhelm the sending and receiving
devices.
• This layer also permits the transmission of
data to Layer 3, the network layer, where it is
addressed and routed.
• Handle errors by implementing an
acknowledgement and retransmission
scheme.
11. Physical Layer
• It co-ordinates the functions required to
transmit bit stream over physical medium.
• Provides physical interface for transmission of
information.
• Defines rules by which bits are passed from one
system to another on a physical communication
medium.
• Covers all - mechanical, electrical, functional
and procedural - aspects for physical
communication.
Introduction to TCP/IP
13. Remembering the 7 Layers
7 - Application All Away
6 - Presentation People Pizza
5 - Session Seem Sausage
4 - Transport To Throw
3 - Network Need Not
2 - Data Link Data Do
1 - Physical Processing Please
14. Que.: Name the layer which is associated with the
transmission media.
Notes de l'éditeur
Purpose of this layer is to provide a reliable mechanism for the exchange of data between two processes in different computers.
Ensures that the data units are delivered error free.
Ensures that data units are delivered in sequence.
Ensures that there is no loss or duplication of data units.
Provides connectionless or connection oriented service.
Layer 1: The physical layer: Transports data using electrical, mechanical or procedural interfaces. This layer is responsible for sending computer bits from one device to another along the network. It determines how physical connections to the network are set up and how bits are represented into predictable signals as they are transmitted either electrically, optically or via radio waves.
The physical layer is responsiblefor the movement of individual bits from one hop (node) to the next.
Physical characteristics of interfaces and medium.
It also defines the type of transmission medium.
Representation of bits.
sequence of 0s or 1s
Data rate.
Synchronization of bits.
Sender and Receiver must be synchronized
Physical topology
Mesh, Ring, Star, etc.
Transmission mode.
Simplex, Half duplex, Duplex