Osi

Osi

• 1.
  Networking Standards and theOSI Model
• 2.
  Networking Standards Organizations •Standards are documented agreements containing technical specifications • ANSI (American National Standards Institute) is an organization composed of more than a thousand representatives from industry and government who together determine standards for the electronics industry and other fields, such as chemical and nuclear engineering, health and safety, and construction
• 3.
  • ANSI alsorepresents the United States in setting international standards • EIA (Electronic Industries Alliance) is a trade organization composed of representatives from electronics manufacturing firms across the United States
• 4.
  • TIA (TelecommunicationsIndustry Association) Focuses on standards for information technology, wireless, satellite, fiber optics, and telephone equipment • TIA/EIA alliance are its guidelines for how network cable should be installed in commercial buildings, known as the “TIA/EIA 568-B Series.”
• 5.
  • IEEE (Instituteof Electrical and Electronics Engineers), or “I-triple-E,” is an international society composed of engineering professionals • IEEE goals are to promote development and education in the electrical engineering and computer science fields
• 6.
  • ISO (InternationalOrganization for Standardization), headquartered in Geneva, Switzerland, is a collection of standards and organizations representing 148 countries • ISO’s goal is to establish international technological standards to facilitate global exchange of information and barrier-free trade
• 7.
  • The ITU(InternationalTelecommunication Union) is a specialized United Nations agency that regulates international telecommunications, including radio andTV frequencies, satellite and telephony specifications, networking infrastructure, and tariffs applied to global communications
• 8.
  • ISOC (InternetSociety), founded in 1992, is a professional membership society that helps to establish technical standards for the Internet • ISOC oversees groups with specific missions, such as the IAB and IETF
• 9.
  • IAB (InternetArchitecture Board) is a technical advisory group of researchers and technical professionals interested in overseeing the Internet’s design and management • IETF (Internet EngineeringTask Force), the organization that sets standards for how systems communicate over the Internet—in particular, how protocols operate and interact
• 10.
  • IANA andICANN • Every computer / host on a network must have a unique address • Internet Assigned Numbers Authority (IANA) kept records of available and reserved IP addresses and determined how addresses were issued out • Internet Corporation for Assigned Names and Numbers (ICANN), a private, nonprofit corporation and is now ultimately responsible for IP addressing and domain name management
• 11.
  The OSI Model •In the early 1980s, ISO began work on a universal set of specifications that would enable computer platforms across the world to communicate openly • This model, called the Open Systems Interconnection (OSI) Model, divides network communications into seven layers:
• 12.
  The OSI Model
• 13.
  Application Layer • Atthe very top of the OSI Reference Model stack of layers • the application layer is the one that is used by network applications.
• 14.
  Presentation Layer • Protocolsat the Presentation layer accept Application layer data and format it • Serves as a translator and are the standards which are involved in multimedia • Presentation layer protocols perform the coding, compression and also manage data encryption and decryption
• 15.
  Session Layer • Protocolsin the Session layer coordinate and maintain communications between two nodes • Session refers to a connection for ongoing data exchange between two parties
• 16.
  Transport Layer • Protocolsin theTransport layer accept data from the Session layer and manage end to-end delivery • Ensures that the data is transferred from point A to point B reliably, in the correct sequence, and without errors
• 17.
  • WithoutTransport layerservices, data could not be verified or interpreted by its recipient • Handles flow control • SomeTransport layer protocols take steps to ensure that data arrives exactly as it was sent.
• 18.
  Network Layer • Primaryfunction of protocols at the Network layer • Translate network addresses • Decide how to route data • Network layer addresses • Also called logical addresses or virtual addresses
• 19.
  Data Link Layer •Primary function of protocols is to divide data into distinct frames that can then be transmitted by the Physical layer • IEEE has divided the Data Link layer into two sublayers • Logical Link Control (LLC) • Media Access Control (MAC)
• 20.
  Physical Layer • Protocolsat the Physical layer • Accept frames from the Data Link layer • Generate voltage so as to transmit signals • Receiving data detect voltage and accept signals • Pass on to the Data Link layer