CEN604 Computer Networks Overview

Course Information:
- Instructor: Dr. Ibrahim Alsukayti
- Email: [email protected]
- Credit Hours: 3
- Schedule: Monday (12:30 - 2:10 pm) & Monday (2:30 - 4:10 pm)
- Assessment:
  - Mid-Term 1: 20%
  - Homework & Quizzes: 10%
  - Project: 20%
  - Final Exam: 50%

Recommended Textbook: "Computer Networking: A Top Down Approach" by Jim Kurose & Keith Ross (Addison-Wesley)
Other Suggested Books:
- "Computer Networks: A Systems Approach" (Peterson and Davie)
- "Data Communication and Networking" (Behrous A. Forouzan)
Course Outline:
- Chapter 1: Introduction to Computer Networks & The Internet
- Chapter 2: Application Layer
- Chapter 3: Transport Layer
- Chapter 4: Network Layer
- Chapter 5: Link Layer
- Chapter 6: Wireless & Mobile Networks
- Chapter 7: Multimedia Networking
- Chapter 8: Security in Computer Networks
- Chapter 9: Network Management

Chapter Goal: Provide an overview and roadmap of computer networks.
Key Concepts:
- Network: A collection of interconnected devices (nodes) for data transmission and resource sharing.
- Internet: A global network connecting networks of various types, including telephone networks, cable TV networks, and computer networks.

Telephone Networks: Dedicated to voice data and connect special-purpose devices.
Cable TV Networks: Dedicated to video data and connect special-purpose devices.
Computer Networks: Support diverse data types (text, voice, video) and utilize general-purpose programmable hardware enabling a wide range of applications.

Components:
- Data Message: The information being transmitted.
- Sender: The device originating the message.
- Receiver: The device receiving the message.
- Medium: The physical path over which data travels.
- Protocol: A set of rules governing data transmission.

Components:
- Sender & Recipient: Addressing ensures message delivery.
- Hierarchical Post Offices (POs): Local, Regional, and Central POs form a network for package routing.
- Package Routing: Packages are redirected based on their destination address (zip code) and handled by different PO levels.

Network Types: Access Networks (e.g., residential, institutional, mobile), ISP (Internet Service Provider), Content Provider Network, Enterprise Network.
Internet: A "network of networks" connecting various network types, including regional ISPs, content providers, data centers, home networks, and enterprise networks.
- Tier-1 ISPs: Large national & international networks with extensive interconnections.
- Content Provider Networks: Private networks connecting content provider data centers directly to the Internet, often bypassing Tier-1/regional ISPs.
- IXPs (Internet Exchange Points): Connect access networks to ISPs and content provider networks.

Link: Physical connection between transmitter and receiver.
Guided Media: Signals propagate through solid media like copper, fiber, and coaxial cables.
Unguided Media: Signals propagate freely through space, e.g., radio waves.
Twisted Pair (TP): Two insulated copper wires used for data transmission (e.g., Category 5 & 6 for Ethernet).
Coaxial Cable: Two concentric copper conductors for bidirectional broadband data transmission.
Fiber Optic Cable: Glass fiber carrying light pulses for high-speed, low-error data transmission.
Wireless Media: Signals transmitted through radio waves (e.g., WiFi, cellular networks, Bluetooth).

Packet: Data broken into smaller chunks for transmission.
Transmission Rate (R): The speed at which data is transmitted over a link (also known as link capacity or bandwidth).
Transmission Delay: Time taken to transmit a packet over a link (calculated as packet size (L) / transmission rate (R)).

Layering is a method of organizing complex systems.
It makes them easier to understand, maintain, and update.
Each layer implements a service and relies on the services provided by the layer below.

Explicit structure allows for identification of the system's pieces and their relationships.
Modularization eases maintenance and updating of the system, as changes in one layer's service implementation are transparent to the rest of the system.

The Internet Protocol (IP) stack is a layered model for internet communication.
The layers are: Application, Transport, Network, Link, and Physical.
Each layer provides services to the layer above it and utilizes the services of the layer below it.

Provides support for applications such as:
- HTTP (Hyper Text Transfer Protocol)
- IMAP (Internet Message Access Protocol)
- SMTP (Simple Mail Transfer Protocol)
- DNS (Domain Name System)

Manages the transfer of data between processes, using services from the network layer.
Protocols include:
- TCP (Transmission Control Protocol)
- UDP (User Datagram Protocol)

Provides routing of datagrams between source and destination, utilizing the link layer.
This layer determines the best route for data packets to move across the internet.
Protocols include:
- IP (Internet Protocol)
- Routing Protocols

Transfers data between neighboring network elements.
This layer handles the physical connections between devices on a network.
Common link layer protocols include:
- Ethernet
- 802.11 (Wi-Fi)
- PPP (Point-to-Point Protocol)

The process of encapsulating data within headers at each layer is essential for transferring data within the IP stack.
The headers contain information that helps each layer perform its specific function.

Message: The original data payload, e.g., message text in an email
Segment: Transport layer header (Ht) encapsulating the message
Datagram: Network layer header (Hn) encapsulating the segment
Frame: Link layer header (Hl) encapsulating the datagram
Bits: The physical layer header (Hl) encapsulating the frame
The encapsulation process continues as the data packet moves through the layers of the IP stack.
The headers are stripped off as the data reaches its destination and travels back up the stack.