2. ◦ Identify organizations that set standards for networking ◦ Describe the purpose of the OSI Model and each of its layers ◦ Explain specific functions belonging to each OSI Model layer ◦ Understand how two network nodes communicate through the OSI Model ◦ Discuss the structure and purpose of data packets and frames ◦ Describe two types of addressing covered by the OSI Model

3. ◦ When we speak of networking standards we are actually talking about the documented agreements containing technical specifications or other precise criteria that stipulate how a particular product or service should be designed or performed. ◦ It is important to remember that standards define the minimum acceptable performance of a product or service.

4.  American National Standards Institute - ANSIANSI ◦ Determines standards for the electronics, chemical, nuclear, health, construction, and safety  Telecommunications Industry Alliance/Electronic Industries Alliance - TIA/EIATIAEIA ◦ In 1988 these two organizations merged and provide standards for information technology, wireless, satellite, fiber optics, and telephone equipment  Institute of Electrical and Electronics Engineers – IEEEIEEE ◦ Promotes development and education in electrical engineering and computer science fields  International Organization for Standardization – ISOISO ◦ Establishes international technological standards to facilitate global exchange of information and barrier-free trade  International Telecommunication Union – ITUITU ◦ Regulates international telecommunications including: radio and TV frequencies, satellite and telephony specifications, networking infrastructure, and tariffs applied to global communications  Internet Society – ISOCISOC ◦ Establishes standards for the Internet  Internet Assigned Numbers Authority – IANAIANA ◦ Early non-profit group that kept records of available and reserved IP addresses  Internet Corporation for Assigned Names and Numbers - ICANNICANN ◦ Formed in the late 1990’s, and is ultimately responsible for IP addresses and domain name management

5.  Was developed in the early 1980s by the ISO  Used primarily for understanding and developing computer- to-computer communications  Gives a theoretical representation of what happens when two nodes communicate.  Divided into 7 layers  Layers 5-7 are essentially software related  Layers 1-4 are considered hardware related  Each layer communicates to its corresponding layer on the distant end  At each layer, protocols handle services unique for that layer. These same protocols pass information to the layer above or the layer below.  Uses a process called encapsulation – upper layer to lower layers  Uses de-encapsulation to go from lower layers to upper layers

7.  Manages the network connection between an application and the network  Includes programs such as web browsers, e-mail clients, command shells, and office applications  An example is when you use a command to perform a network print job. The print subsystem used to communicate this to the network is an Application Layer application  Uses the largest set of network protocols such as:  HTTP  FTP  SMTP  POP

8.  Formats Application Layer data passed down The server normally has more processing power, storage capacity, and memory than clients ◦ Encrypts and compresses data from the Application Layer ◦ Common methods for encoding and compressing graphics  GIF  TIFF  JPG ◦ Popular audio encoding and compression methods are:  MPEG  QuickTime ◦ Decrypts data being passed up from the Session Layer

9.  The term session refers to a connection that is ongoing  Provides the means for creating and managing sessions as well as providing the services needed to initiate those sessions  Functions include:  Keeping link alive for duration of the session  Synchronizing the dialogue  Speed  Duplex  Half-duplex – single direction  Full-duplex – both directions simultaneously  Error detection and correction

10.  Primary function of the transport layer is to segment session data into the Maximum Transmission Unit (MTU) and pass appropriately sized and formatted data to the Network Layer  Provides connection-oriented/reliable (acknowledgements required) data transmissions – Transmission Control Protocol (TCP)  Provides connectionless-oriented/unreliable (no acknowledgements required) data transmissions – User Datagram Protocol (UDP)  Provides a direct link that exist between two network OSI stacks during any communications  Manages the connection between two adjacent layers  Manages connections using windowing, flow control, and sequencing

11.  Provides logical addressing (IP addresses)  Routing (path determination - Uses delivery priorities, network congestion, Quality of Service (QOS), and cost of alternative routes)  Packet switching  It encapsulates segments into packets.  Uses routed protocols such as IP and routing protocols such as RIP, RIPv2, IGRP, EIGRP, and OSPF.  Routers operate at this level. Routers are commonly referred to as layer 3 devices

13.  Encapsulates packets into frames  Has 2 sub-layers ◦ Logical Link Control (LLC) – 802.2 - provides common interface, reliability, and flow control  Identifies layer 3 protocols and encapsulates them into frames so that the data can be transported across the network  Uses type code identifiers known as SAPs ◦ Media Access Control (MAC) – 802.3 - provides physical addressing – MAC addresses  Responsible for how the frames are transmitted down the physical wire  Defines functions such as; physical addressing, network topology, line discipline, error notification, orderly delivery of frames, and optional flow control

15.  All networking devices have a permanent MAC address – Burned-in address (bia)  MAC addresses are 48 bit long and are displayed as hexadecimal characters divided into 2 parts: ◦ The block ID – 24 bits long  First 6 characters of the MAC address  Unique to each vendor ◦ The device ID – 24 bits long  Last 6 characters  Unique to each device

16.  Turns frames into electrical impulses that when issued in a certain pattern represent data (normally represented as 1s and 0s)  Copper wire – electrical impulses are issued as volt charges (+ or – 5 volts)  Fiber optics – electrical impulses are issued a light pulses  Wireless – sent from antennas as electromagnetic waves  Hubs and repeaters operate at this layer  Set data rates and monitors error rates

17.  802.1 – Routing, bridging, and network-to- network communications  802.2 – Logical Link Control – error and flow control over data frames  802.3 – Ethernet LAN – all forms of Ethernet media and interfaces  802.5 – Token Ring LAN – all forms of token ring media and interfaces  802.11 – Wireless networks – standards for wireless networking for many different broadcast frequencies and usage techniques  802.15 – Wireless personal area networks – the coexistence of wireless personal area networks with other wireless devices in unlicensed frequency bands  802.16 – Broadband wireless and metropolitan area networks – the atmospheric interface and related functions associated with Broadband wireless connectivity…also known as WIMAX  802.17 – Resilient packet rings – Access method, physical layer specifications and management of shared packet-based transmission on resilient rings such as SONET  802.20 – Mobile Broadband wireless – packet handling and other specifications for multivendor mobile high-speed wireless transmission, sometimes called mobile WIMAX  802.22 – Wireless regional area networks (WRAN) – wireless broadcast style network to operate in the UHF/VHF frequency bands formerly used for TV channels

18. For more information on this lesson, See Chapter 2 in the text book or email the Professor **All Slides and graphics were produced by Professor Patrick Hughes**