OSI Refrance Model

OSI MODEL

1. THE OSI MODEL WAS DEVELOPED BY THE INTERNATIONAL ORGANIZATION FOR STANDARDIZATION (ISO) IN THE LATE 1970S. THE MAIN ARCHITECT OF THE OSI MODEL WAS HUBERT ZIMMERMANN, A FRENCH SOFTWARE ENGINEER.

2.  ISO REPRESENT A 1947 MORE THAN WORK AND AGAIN REPRESENTS A ISO IN 1977 AND MORE THAN WORK AN REPRESENT  IN 1983 A OSI REDFRENCE MODEL.

2. HIS MODEL REPRESENT A 7 LAYER

3. OSI MEANS  (OPEN SYSTEMS INTERCOMMUNICATIO).

1. APPLICATION LAYER

1. THE APPLICATION LAYER IS USED BY END-USER SOFTWARE SUCH AS WEB BROWSERS AND EMAIL CLIENTS. 

IT PROVIDES PROTOCOLS THAT ALLOW SOFTWARE TO SEND AND RECEIVE INFORMATION AND PRESENT MEANINGFUL DATA TO USERS.

2. IT SENDS ITS DATA TO THE FORM OF THE PDU.

PROTOCLS  AND DEVICES USED IN LAYER

THERE ARE SOME PROTOCOLS THAT WORK AT THE BACKEND OF THE APPLICATION LAYER.

WHICH IN TURN WORKS AT THE APPLICATION LAYER.MANY DEVICES USE IT AT THE APPLICATION LAYER.

PROTOCOLS

FTP  (FILE TRANSOFER PROTOCOL)

DNS (DOMAIN NAME SYSTEM)

HTTP (HYPER TEXT TRANSFOR PROTOCOL)

DEVICES

ALL END DEVICES USED IN LAYER.

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2. PRESENTATION LAYER

1. THE PRESENTATION LAYER RECEIVED  THE DATA FROM APPLICATION LAYER AND PROCESSES THE RAW DATA AND THEN COMPRESSES THE DATA AND ENCODE THE DATA SO SESSION LAYER EASILY RECIEVE THE DATA.

2. PRESENTATION LATER SENDS ITS DATA IN PDU FORMAT. 

THERE ARE SOME PROTOCOLS THAT WORK AT THE BACKEND OF THE PRESENTATION LAYER.

WHICH IN TURN WORKS AT THE PRESENTATION LAYER.MANY DEVICES USE IT AT THE APPLICATION LAYER.

PROTOCOLS

NCP  (NETWARE CORE PROTOCOL)

LPP (LINEAR PROGRAMMING PROBLEM)

DEVICES

GATEWAY OR FIREWALL OR PC.

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3. SESSION LAYER

1. IT IS USED TO MANAGE USER CONNECTIONS SESSION LAYER CONTROLS THE CONNECTION BETWEEN COMPUTERS.

2. IT ESTABLISHES, MANAGES AND TERMINATES CONNECTIONS BETWEEN USERS OR REMOTE APPLICATIONS.

3. IT TRANSMITS ITS DATA IN PDU FORM.

PROTOCLS  AND DEVICES USED IN LAYER

THERE ARE SOME PROTOCOLS THAT WORK AT THE BACKEND OF THE SESSION LAYER.

WHICH IN TURN WORKS AT THE SESSION LAYER.MANY DEVICES USE IT AT THE APPLICATION LAYER.

PROTOCOLS

  PPTP (POINT-TO-POINT TUNNLING PROTOCOL)

  RPC (REMOTE PROCRDURE CAL PROTOCOL)

  SCP (SESSION CONTROLL PROTOCOL)

DEVICES

GATEWAY OR FIREWALL OR PC.

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4. TRANSPORT LAYER

1. WHEN OUR DATA MOVES FROM ONE PLACE TO ANOTHER, CONTROLS THE DATA FLOW. 

2. IF ANY PROBLEM OCCURS DURING DATA TRANSFER, IT RESOLVES IT. 

3. IF THE DATA IS MORE, IT CONVERTS AND TRANSFERS THIS DATA IN SEGMENTS SO THAT THERE IS NO PROBLEM IN THE DATA AND YOUR DATA IS EASILY TRANSFERRED.

4.  IT SENDS ITS DATA IN THE FORM OF SEGMENTS.

PROTOCLS  AND DEVICES USED IN LAYER

THERE ARE SOME PROTOCOLS THAT WORK AT THE BACKEND OF THE TRANSPORT LAYER.

WHICH IN TURN WORKS AT THE TRANSPORT LAYER.MANY DEVICES USE IT AT THE APPLICATION LAYER.

PROTOCOLS

  TCP (TRANSMISSION CONTROLL PROTOCL)

  UDP (USER DATAGROUND PROTOCOL)

DEVICES

GATEWAY OR FIREWALL PC.

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5. NETWORK LAYER

1. THE NETWORK LAYER CHOSES BEST PATH YOUR PACKET  AND THEN FORWARDS IT FORWARD SO THAT THERE IS NO PROBLEM IN FORWARDING THE PACKET

2. NETWORK LAYER ALLOWS THE TRANSFER OF DATA PACKET OF CONNECTIONS BETWEEN NETWORKS.

3. IT SENDS ITS DATA IN THE FORM OF PACKET

PROTOCLS  AND DEVICES USED IN LAYER

THERE ARE SOME PROTOCOLS THAT WORK AT THE BACKEND OF THE NETWORK LAYER.

WHICH IN TURN WORKS AT THE NETWORK LAYER.MANY DEVICES USE IT AT THE APPLICATION LAYER.

PROTOCOLS

  IPV4 (INTERNET PROTOCOL VERSION 4)

    IPV6 (INTERNET PROTOCOL VERSION 6)

ICMP (INTENET CONTROLLL MESSAGE PRTOCOL)

DEVICES

ROUTER.

MULTY LAYER SWITCH.

_________________

6. DATA LINK LAYER 

THE DATA LINK LAYER BREAKS DATA UP INTO SMALLER UNITS CALLED FRAMES.

IT ADDS ERROR-CHECKING INFORMATION TO EACH FRAME.

IT TRANSMITS THE FRAMES ACROSS THE PHYSICAL LAYER.

IT HANDLES FLOW CONTROL, WHICH ENSURES THAT THE SENDER DOES NOT SEND DATA FASTER THAN THE RECEIVER CAN RECEIVE IT.

IN OTHER WORDS, THE DATA LINK LAYER IS RESPONSIBLE FOR ENSURING THE RELIABLE DELIVERY OF DATA BETWEEN TWO NODES ON A NETWORK. IT DOES THIS BY ADDING ERROR-CHECKING INFORMATION TO EACH FRAME, AND BY RETRANSMITTING FRAMES THAT ARE CORRUPTED OR LOST. THE DATA LINK LAYER ALSO HANDLES FLOW CONTROL, WHICH ENSURES THAT THE SENDER DOES NOT OVERWHELM THE RECEIVER.

PROTOCLS  AND DEVICES USED IN LAYER

THERE ARE SOME PROTOCOLS THAT WORK AT THE BACKEND OF THE DATA LINK LAYER.

WHICH IN TURN WORKS AT THE DATA LINK LAYER .MANY DEVICES USE IT AT THE APPLICATION LAYER.

PROTOCOLS

(PPP)  Point To Point Protocol.

(LCP)  Link Control Protocol 

(LAP)   Link Access Procedure.

(NCP ) Network Control Protocol .

DEVICES

NIC

WIRELESS ACCESS POINT

ETHERNET SWITCH.

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7.PHYSICAL LAYER

THE PHYSICAL LAYER TRANSMITS AND RECEIVES DATA BITS OVER A COMMUNICATION CHANNEL.

IT DOES THIS BY ENCODING THE DATA BITS INTO A PHYSICAL SIGNAL, SUCH AS A VOLTAGE LEVEL OR LIGHT PULSE.

IT ALSO ENSURES THAT THE DATA BITS ARE TRANSMITTED AND RECEIVED IN A SYNCHRONIZED MANNER.

THE PHYSICAL LAYER MAY ALSO BE RESPONSIBLE FOR DETECTING AND CORRECTING ERRORS IN THE DATA BITS THAT ARE TRANSMITTED.

IN OTHER WORDS, THE PHYSICAL LAYER IS RESPONSIBLE FOR THE PHYSICAL ASPECTS OF DATA TRANSMISSION, SUCH AS THE TYPE OF SIGNAL USED, THE SPEED OF TRANSMISSION, AND THE ERROR DETECTION AND CORRECTION MECHANISMS.

PROTOCLS  AND DEVICES USED IN LAYER

THERE ARE SOME PROTOCOLS THAT WORK AT THE BACKEND OF THE PHYSICAL LAYER.

WHICH IN TURN WORKS AT THE DATA LINK LAYER .MANY DEVICES USE IT AT THE APPLICATION LAYER.

PROTOCOLS

1. ETHERNET

2. BLUETOOTH.

3. DSL 

4. WIFI

DEVICES

CABLE

CONNECTOR

NETWORK INTERFACE CARD

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OSI Layer	PDU Name	Key Header Information
Application	Data	User data, no header added here.
Presentation	Data	Data is formatted, compressed, or encrypted.
Session	Data	Manages session state, no new header added.
Transport	Segment	Source/Destination ports, Sequence number, Acknowledgment, etc.
Network	Packet	Source/Destination IP, TTL, Protocol, Header checksum.
Data Link	Frame	MAC addresses, Type, FCS for error checking.
Physical	Bits	0s and 1s for transmission as electrical/radio/optical signals.

 

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