DEVELOPMENT HISTORY ABOUT
OSI THE MODEL
IN THE LATE 1970 TWO GROUPS CAME TOGETHER WITH THE GOAL OF TO DEFINE A SPECIFIC STANDARD FOR THE ARCHITECTURE OF NETWORKING SYSTEMS.
ONE KNOW AS INTERNATIONAL ORGANIZATION FOR STANDARDIZATION (ISO) AND THE OTHER INTERNATIONAL TELEGRAPH AND TELEPHONE CONSULATIVE COMMITTEE.
EACH ORGANIZATION DEVELOPS A
DOCUMENT AND IN 1983 THE DOCUMENTS WERE MERGE TOGETHER.
TO FORM THE REFERENCE MODEL OF THE OPEN
SYSTEM INTERCONNECT IN 1984. AND THE CONCEPT OF THE SEVEN LAYERS WAS PROVIDER BY
CHARLES BACH MAN. EACH LAYER WORKS DIRECTLY WITH THE LAYER BENEAT IT, AND
PROVIDE SERVICES FOR LAYER ABOVE IT.
WHAT IS AN OSI MODEL
MEANING OF THE ABBREVIATION IS OPEN SYSTEM INTERCONNECT.
OSI IS A REFERENCE MODEL ARCHITECTURE THAT ENABLE DIFFERENT NETWORK TO
COMMUNICATE RELIABLE BETWEEN DIFFERENT SYSTEM.
SOME ADVANTAGES OF THE OSI REFERENCE MODEL
1. ALLOWS DIFFERENT VENDORS OF NETWORKS TO INTER OPERATE.
2. IT ALLOWS VARIOUS
TYPES OF NETWORK AND HARDWARE TO
COMMUNICATE.
3.
DIVIDES NETWORK
COMMUNICATION INTO SMALLER AND SIMPLER FORM COMPONENT WHICH AID IN TROUBLE
SHOOTING.
4.IT ENCOURAGES
INDUSTRIAL STANDARDIZATION BY DEFINING WHAT STANDARDS OCCUR AT EACH LAYER OF
THE MODEL.
5.IT PREVENT CHANGES IN
ONE LAYER FROM AFFECTING THE OTHER LAYER.
PHYSICAL
LAYER
IT REPRESENTS THE NETWORK MEDIA AND DEVICES.ITS MAIN
FUNCTION IS TO PROVIDE AN INTERFACE FOR TRANSMISSION OF INFORMATION. ITS
CHARACTERISTICS ARE PHYSICAL DATA RATES AND PHYSICAL CONNECTORS.
SOME DEVICES THAT WORK AT THESE LAYER HUBS, NIC, REPEATERS, MODEM. SOME PROTOCOLS THAT WORK AT THESE LAYER ARE DSL, USB, ISDN, IRDA.
SOME DEVICES THAT WORK AT THESE LAYER HUBS, NIC, REPEATERS, MODEM. SOME PROTOCOLS THAT WORK AT THESE LAYER ARE DSL, USB, ISDN, IRDA.
DATALINK LAYER
IT REPRESENTS WAYS OF TRANSFERRING DATA BETWEEN
DEVICES. BY THE USE OF FRAMES. ITS MAIN CHARACTERS IT IMPLEMENT FLOW
CONTROL,SUPPORT POINT TO POINT AS WELL AS BROADCAST INFORMATION AND HALF DUPLEX
AND FULL DUPLEX COMMUNICATION.
SOME DEVICES THAT WORK AT THIS LAYER ARE SWITCHES, NETWORK ADAPTER, BRIDGES, WIRELESS ACCESS POINT.SOME PROTOCOLS THAT WORK AT THIS LAYER ARE PPP, CDP, FDDI, LAPD.
SOME DEVICES THAT WORK AT THIS LAYER ARE SWITCHES, NETWORK ADAPTER, BRIDGES, WIRELESS ACCESS POINT.SOME PROTOCOLS THAT WORK AT THIS LAYER ARE PPP, CDP, FDDI, LAPD.
NETWORK LAYER
IT’S THE LAYER RESPONSIBLE FOR MOVING DATA
AROUND A NETWORK OF NETWORKS. KNOWN AS AN INTERNET WORK OR INTERNET.ITS
PROVIDES ADDRESS PATHS FOR FRAMES (PACKETS). ITS HANDLES CONGESTION IN THE
NETWORK AND FRAGMENTS PACKETS AND PROVIDES OPTIMUM PATH FOR PACKETS.
SOME DEVICES THAT OPERATE AT THESE LAYER ROUTERS, BASIC FIREWALLS, LAYER 3 SWITCHES. SOME PROTOCOLS THAT WORK AT THIS LAYER IP, ICMP, ARP, IGMP
TRANSPORT LAYER
ITS KNOW AS AN END TO END LAYER PROTOCOL RESPONSIBLE
FOR ENSURING RELIABLE DELIVERY OF DATA. DUE TO ITS RELIABLE MECHANISM IT HELPS
TO EXCHANGE DATA BETWEEN TWO PROCESS IN DIFFERENT COMPUTERS AND PROVIDES
CONNECTION FOR SERVICES ORIENTED. IT
BREAKS MESSAGES FROM THE SESSION LAYER INTO PACKET FORMAT.
SOME DEVICES THAT WORKS AT THIS LAYER MULTI LAYER SWITCHES, FIREWALLS, IDS. SOME PROTOCOLS THAT WORK AT THIS LAYER TCP,UDP.
SOME DEVICES THAT WORKS AT THIS LAYER MULTI LAYER SWITCHES, FIREWALLS, IDS. SOME PROTOCOLS THAT WORK AT THIS LAYER TCP,UDP.
SESSION LAYER
ITS HELPS TO
START, CONTROL AND END CONVERSATIONS KNOWN AS (SESSIONS) BETWEEN
APPLICATIONS. ITS ALSO RESPONSIBLE FOR TERMINATING CONNECTION. ITS ALSO
PROVIDES
SERVICES LIKE DIALOGUE AND DISCIPLINE.
SOME DEVICES THAT OPERATE AT THIS LAYER OF THE OSI REFERENCE MODEL ARE WALKIE TALKIE, GATEWAY. SOME PROTOCOLS THAT WORK AT THESE LAYER OF THE OSI MODEL NFS,SIP,PTP, (TLS/SSL).
SOME DEVICES THAT OPERATE AT THIS LAYER OF THE OSI REFERENCE MODEL ARE WALKIE TALKIE, GATEWAY. SOME PROTOCOLS THAT WORK AT THESE LAYER OF THE OSI MODEL NFS,SIP,PTP, (TLS/SSL).
PRESENTATION LAYER
ITS THE SECOND
LAYER FROM THE TOP OF THE OSI REFERENCE LAYER MODEL. IT DEFINES A FORMAT OR
STANDARD IN WHICH DATA NEEDS TO BE EXCHANGE BETWEEN TWO COMMUNICATION ENTITIES . AND ALSO
PRESENTS DATA TO THE APPLICATION LAYER.COMPRESSION AND ENCRYPTION. THIS LAYER MAKES IT POSSIBLE FOR COMPUTERS
WITH DIFFERENT REPRESENTATION TO COMMUNICATE.
SOME DEVICES THAT WORKS AT THIS LAYER OF THE OSI MODEL COMPUTERS AND MOBILE PHONES . SOME PROTOCOLS THAT WORK AT THESE LAYER OF THE OSI MODEL ARE HTTP, TLS,SSL.
SOME DEVICES THAT WORKS AT THIS LAYER OF THE OSI MODEL COMPUTERS AND MOBILE PHONES . SOME PROTOCOLS THAT WORK AT THESE LAYER OF THE OSI MODEL ARE HTTP, TLS,SSL.
APPLICATION
LAYER
ITS THE HIGHEST LAYER OF THE OSI MODEL. IT PROVIDES SERVICES FOR AN APPLICATION
PROGARM TO ENSURE EFFECTIVE COMMUNICATION WITH ANOTHER APPLICATION PROGARM
IN A NETWORK IS POSSIBLE. IT INTERACTS WITH THE APPLICATION PROGARMS. SUCH AS
FILE TRANSFER, ELECTRONIC MAIL, REMOTE LOGIN AND SO ON.ITS THE ENDING OF DATA
TRANSFER. AT THIS POINT DATA IS A VISUAL FORM.
SOME DEVICES THAT WORK AT THESE LAYER OF THE OSI MODEL PROXY AND FIREWALL SERVERS. SOME PROTOCOLS THAT WORKS AT THESE LAYER OF THE OSI MODEL TFTP,DNS,SMTP,SNMP.
SOME DEVICES THAT WORK AT THESE LAYER OF THE OSI MODEL PROXY AND FIREWALL SERVERS. SOME PROTOCOLS THAT WORKS AT THESE LAYER OF THE OSI MODEL TFTP,DNS,SMTP,SNMP.
THE OSI REFERENCE MODEL IS A TOOL THAT HELPS TO SIMPLIFY NETWORK DESIGN, MANAGE AND TROUBLESHOOT NETWORKS IT’S A PRIMARY ARCHITECTURE FOR INTER COMPUTER COMMUNICATIONS.
TAGS:
PHYSICAL LAYER= BINARY TRANSMISSION,DATA-LINK LAYER= MEDIA
ACCESS,NETWORK LAYER= ADDRESS PATH (PACKETS), TRANSPORT LAYER= END TO
END CONNECTIONS,SESSION LAYER= INTER HOST COMMUNICATION,PRESENTATION
LAYER= DATA REPRESENTATION,APPLICATION LAYER= NETWORK PROCESS TO
APPLICATION.