Transcript data networking protocals

WELCOME
TO
P.P.T ON VOCATIONAL TRAINING
from-;
SUHEL KHAN
AND
ROSHINI GUPTA
ETC
ETC
DATA NETWORKING PROTOCALS
Protocol
•Protocol is a set of rules

A protocol consists of guidelines for:
– How data is formatted into discrete units
called packets and frames
– How packets and frames are transmitted
across one or more networks
– How packets and frames are interpreted at
the receiving end
6. Network Model
Who define Network Model?
• Need non-profit making organizations
• ISO - International Standards Organization
e.g. OSI, MPEG-1, 2, 4, etc. (http://www.iso.ch/)
• IEEE - Institute of Electrical & Electronic
Engineers
e.g IEEE 802, IEEE 754, etc. (http://www.ieee.org)
• ITU - International Telecommunication Union
e.g. V.34, H.323, H.324, etc. (http://www.itu.int)
The OSI 7-layer Model
• OSI - Open Systems Interconnection
• Defined in 1984 and become an international standard
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Data
Not
Do
Processing
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Pizza
Sausage
Layered Architecture
• Layering specifies different level
of functions and services
• Each layer works with the layer
below and above it
• Each layer provides services to
next layer
• Shield the upper layer from the
details of actual implementation
Protocols in a layered architecture
• Network communication is possible only if
machines speaking the same languages (protocols)
• Since each layer work independently, each layer
speaks different languages (protocols)
• Lead to the concept of a Protocol Stack
• Network communication is possible only if the
Protocol Stacks on two machines are the same
• To identify the language (protocol) of each layer,
identifier (header and trailer) are added to data
1. Physical Layer
Example protocols: Ethernet, Token Ring (Physical part)
Appl.
Appl.
Pres.
Pres.
Sess.
Sess.
• Max/min electrical voltage?
Tran.
Tran.
• Responsible for transmitting
bits from one computer to
another
Netw.
Netw.
Data.
Data.
Phys.
Phys.
• Define how cable is attached to
the Network Adapter Card
• How many pins in the connector?
• The impedance?
2. Data Link Layer
Example protocols: Ethernet, Token Ring
• Make data frames
Frame
• Provide error-free frame
transfer by acknowledgment
and retransmission
Appl.
Appl.
Pres.
Pres.
Sess.
Sess.
Tran.
Tran.
Netw.
Netw.
Data.
Data.
Phys.
Phys.
3. Network Layer
Example protocols: IP, IPX
• Logical address to physical
address translation
For TCP/IP running on Ethernet
Logical address: IP address
158.132.148.99
Physical address: Ethernet address
00 00 E2 15 1A CA
• Determine the route from
source to destination computer
Appl.
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Sess.
Sess.
Tran.
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Netw.
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4. Transport Layer
Example protocols: TCP, SPX, NWLink
• Ensure packets are delivered
error free, in sequence
• Translate between packets and
message
Appl.
Appl.
Pres.
Pres.
Sess.
Sess.
Tran.
Tran.
Netw.
Netw.
Data.
Data.
Phys.
Phys.
5. Session Layer
Example application program: Winsock, UNIX Socket
• Establishment, maintaining and
release of session
Appl.
Appl.
Pres.
Pres.
• Provide dialog management
Sess.
Sess.
• Regulate which side transmit, Tran.
when, for how long (Sync.)
Netw.
Tran.
• Provide synchronization
between user tasks
Netw.
Data.
Data.
Phys.
Phys.
6. Presentation Layer
Example application program: redirector (NT), SSL
• Translate data from
Application Layer to the
format suitable for session
layer (the network)
• Provide data encryption,
compression
• Changing or converting
character set, graphic, and file
format
Appl.
Appl.
Pres.
Pres.
Sess.
Sess.
Tran.
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Netw.
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7. Application Layer
Example protocols: FTP, Telnet, HTTP
• Entry point for application to
access network
Appl.
Appl.
Pres.
Pres.
• Directly support user
applications
Sess.
Sess.
Tran.
Tran.
Netw.
Netw.
Data.
Data.
Phys.
Phys.
• E.g. File transfer, email
• General capabilities:
Network access, flow control,
Error recovery
Example: File Transfer
• The most traditional network task
• Implemented by a simple Application Layer
protocol called FTP
FTP Client
FTP Server
PictureTel
Network
Chapter Summary
Protocols are the life blood of
a network, thus plan their use
carefully.
For modern networking TCP/IP Plan
to use only the protocols necessary.
Plan to use only the protocols
necessary.
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