chapter 6

The Seven Layers of the OSI Model:

1. Physical Layer (Layer 1)

   • Deals with raw data transmission (bits) over physical media (cables, wireless signals).

   • Includes hardware like network cables, hubs, and repeaters.

2. Data Link Layer (Layer 2)

   • Manages error detection and correction in data transmission.

   • Uses MAC (Media Access Control) addresses.

   • Includes switches and bridges.

3. Network Layer (Layer 3)

   • Handles logical addressing (IP addresses) and routing of data packets.

   • Uses routers to determine the best path for data.

4. Transport Layer (Layer 4)

   • Ensures reliable data transfer between devices using protocols like TCP and UDP.

   • Manages segmentation, flow control, and error recovery.

5. Session Layer (Layer 5)

   • Establishes, maintains, and terminates communication sessions between applications.

6. Presentation Layer (Layer 6)

   • Translates data between different formats (encryption, compression, encoding).

   • Ensures data is readable by the receiving application.

7. Application Layer (Layer 7)

   • Provides network services directly to end users (e.g., web browsing, email, file transfers).

   • Includes protocols like HTTP, FTP, SMTP, and DNS.

   • 
     In data communication, _____ refers to integrating voice, video, and data so that multimedia information can be used for decision making. Why is security concerned when using a wireless network?

     Group of answer choices

     Wireless networks use inferior protocols to those used by wired networks.

     Wireless transmission uses air as a medium so that it can be intercepted easily.

     Wireless networks provide limited throughput.

     Wireless networks allow any user to connect.

   • Which of the following could prevent third parties from reading the data transmitted through your home wireless AP?

     Enable network encryption to WPA2.

   • For a business network keeping connectivity even in the failure of one or several nodes is critical. Which network topology is more adequate to address the requirement?

     Mesh topology

   • Application

     End-user applications and services

     Web browser (Chrome, Firefox), Email (Gmail, Outlook)

     Presentation

     Data translation, encryption, compression

     File formats (JPEG, MP3, PNG), SSL encryption

     Session

     Manages sessions and connections

     Logging into a website (user authentication)

     Transport

     Reliable/unreliable data delivery

     TCP (email, web), UDP (video streaming, VoIP)

     Network

     Routing, addressing (IP addresses)

     Routers, IP addresses, sending data across the internet

     Data Link

     MAC addresses, error detection

     Ethernet, switches, Wi-Fi (802.11)

     Physical

     Physical transmission of bits

     Cables, fiber optics, radio signals

   Planning

   Define project goals, feasibility, resources

   A company decides to develop a mobile app and checks budget & market demand

   Analysis

   Gather requirements, identify risks

   Interviewing users & stakeholders to understand needs

   Design

   Create system architecture, UI/UX

   Drawing wireframes, database schema, and deciding on programming languages

   Implementation (Coding)

   Developers write and build the software

   Writing code using Python, Java, or C++

   Testing

   Find and fix bugs, ensure functionality

   Running test cases, debugging, quality assurance

   Deployment

   Release software for users

   Launching an app on the Play Store or rolling out a website

   Maintenance

   Update, fix bugs, and improve features

   Releasing updates, patching security flaws