Transcript Chapter 2 - William Stallings, Data and Computer

1
Protocol Architecture, TCP/IP, and
Internet-Based Applications
Data and Computer Communications
by William Stallings
Eighth Edition
Networks and
Communication
Department
Click to 2edit Master subtitle style
Chapter
Need For Protocol Architecture
data exchange can involve complex procedures.
better if task broken into subtasks
implemented separately in layers in stack
 each layer provides functions needed to perform functions
for layers above
 using functions provided by layers below
layers communicate using a set of rules known as a protocol.
TCP/IP Protocol Architecture
developed by US Defense Advanced Research Project Agency
(DARPA)
•for ARPANET packet switched network
•used by the global Internet
•
1) TCP/IP Layers
5.Application layer
4.transport layer
3.Network layer
2.Data link layer
1. Physical layer
Physical Layer
The physical layer is responsible transforming data into
bits.
concerned with issues like:
•
characteristics of transmission medium
 Representation of bits and signal levels: how 0,1 are changed
to signals.
 data rates: number of bits sent per second and duration of
bits.
 Synchronization of bits.

Data link Layer
The data link layer is responsible for moving frames from one
hop(node)to the next
•It adds a header to the frame to define the sender and the
receiver of the frame.
•Using physical address(MAC) : the local address of a node as
defined by its LAN pr WAN.
•concerned with issues like:
-Flow control
-Error control
•
Data link Layer
The data link layer is responsible for moving
frames from one hop(node)to the next
Hop-to-hop delivery
Network layer
Network layer is responsible for the delivery of packets from the
source host to the destination host across multiple networks.
•using IP address: 32-bit address that uniquely define a host
connected to the internet.
•routers connect two networks and relays data between them
•
Source-to-destination delivery
Transport Layer (TCP)
Delivery from a specific process on a computer to specific
process on the other
•Using Port address: 16-bit address to choose among multiple
processes on the destination host.
•
Process-to-process delivery
Application Layer
Enables the user to access the network
•
Addressing Requirements
Three levels of addressing required:
•each host on a subnet needs a unique global network address its
IP address
•each application on a (multi-tasking) host needs a unique
address within the host known as a port address
• Physical address
2) OSI
Open Systems Interconnection
•developed by the International Organization for
Standardization (ISO)
•has seven layers
•
OSI Model
Session layer
•The session layer is responsible for dialog control and
synchronization .
•Establish, manage ,terminate session
Presentation layer
•The presentation layer is concerned with the syntax and
semantics of the information exchanged between two
systems
Summary of layers