Welcome

1. Start Welcome The OSI Model Communication,Communication,Communication Jerry Whaley

2. Introduction • Let’s start with a little example of how we communicate in relation to how computers communicate. • Please shake the hand of the person next to you.

3. Layer 1Physical (The Handshake): defines the electrical and physical specifications (maybe some of you got a shock when you first touched). Example of a Frame (Data Link layer protocol) Courtesy Course Technology/Cengage LearningNetwork+ Guide to Networks, 6th Edition Even though the NIC (Network Interface Card) is typically associated as part of the Data Link layer (MAC address – Media Access Control) so is it, in a manner of speaking, part of the Physical layer – accepts frames from the Data Link layer and generates signals.

4. Layer 2Data Link (Hand-Eye Contact): the actual linkage and mechanisms to move data about the network such as topology, Ethernet or Token-Ring, basically how data is transmitted. Example of a Frame (Data Link layer protocol) Courtesy Course Technology/Cengage LearningNetwork+ Guide to Networks, 6th Edition Data Link layer and its sublayers The LLC (Logical Link Control) sublayer provides an interface with the Network layer protocols which appends the physical address of the destination computer onto the data frame.

5. Layer 3Network (GPS): defines the process used to route data across the network (logical addressing). Courtesy Course Technology/Cengage LearningNetwork+ Guide to Networks, 6th Edition Used to translate network addresses into their physical counterparts and decides how to route data from the sender to the receiver.

6. Layer 4Transport (Satellite): provides for reliable transmission of data segments (disassembly and assembly of data before and after transmission). Courtesy Course Technology/Cengage LearningNetwork+ Guide to Networks, 6th Edition Ensures data is transferred for one computer to the next reliably, in the correct sequence, and hopefully without error.

7. Layer 5Session (GPS & Satellite People): establishes, maintains, and manages communications between computers. Courtesy Course Technology/Cengage LearningNetwork+ Guide to Networks, 6th Edition Refers to a connection for ongoing data exchange between two parties. Sort-of like making a phone call and having a conversation. (can you hear me now?)

8. Layer 6Presentation (You, your appearance): concerned with data representation and code formatting. Courtesy Course Technology/Cengage LearningNetwork+ Guide to Networks, 6th Edition May be referred to as the translator. Accepts Application layer data and formats it so one application/host can understand another application/host.

9. Layer 7Application (Web Page): provides services to the software and your request for network services like the browser and email client(s) (like a negotiator). Courtesy Course Technology/Cengage LearningNetwork+ Guide to Networks, 6th Edition Serves as the window for users and application processes to access network services. This layer contains a variety of commonly needed functions. (Microsoft Support - Article ID: 103884 - Last Review: February 27, 2002 - Revision: 1.0)

10. History • Does anyone have an idea of about when OSI Model (Open Systems Interconnection Reference Model) came about? • (Think about when the personal computer made an appearance) • Do you recall hearing all this talk about standardization? • (Remember OSHA – Occupational Safety and Health Organization).

11. Standards • Well ISO (International Organization for Standardization) developed the OSI model in an effort to set a standard by suggesting, proposing, and recommending the steps to transfer data from one network device to another. • Another words an open platform for the world to communicate from one computer to another over a network.

12. Reasoning • You can probably see how important having some kind of standard today especially with all the various computer manufacturing companies there are, all the components that are used in a single computer, and of course the massive internet system and resources available. • Even all the social networking tools out there that are free to explore and manipulate you need some kind of standard to help keep it all together and hopefully safe from those that take advantage of the innocent.

13. Summary • You always hear how important location, location, location is, yet communication is also quite critical and important. • Here’s an interesting way to look at this concept; Doug Lowe (an author for Dummies.com) puts it “These layers are kind of like the layers of an onion: Each successive layer envelops the layer beneath it, hiding its details from the levels above. The OSI model is also like an onion in that if you start to peel it apart to have a look inside, you’re bound to shed a few tears.” I believe his intentions where to represent the onion as tears of joy.

14. References: Dean, T. (2013). Network+ Guide to Networks. (6th ed.). Boston, MA: Course Technology, Cengage Learning. Microsoft Support (2002, February 27). ID: 103884 . The OSI Model's Seven Layers Defined and Functions Explained. Retrieved July 23, 2013, from http://support.microsoft.com/kb/103884 Dummies.com (n.d.). Getting to Know the OSI Model for the CCNA Exam. Reasons for a layered model. Retrieved July 23, 2012, from http://www.dummies.com/how-to/content/getting-to-know-the-osi-model-for-the-ccna-exam.html Dummies.com (n.d.). Network Basics. The Seven Layers of the OSI Reference Model. Retrieved July 23, 2012, from http://www.dummies.com/how-to/content/network-basics-the-seven-layers-of-the-osi-referen.html Microsoft Support (2002, February 27). ID: 103884 . The OSI Model's Seven Layers Defined and Functions Explained. Retrieved July 23, 2013, from http://support.microsoft.com/kb/103884