Data Communications and Networking Class Rules

Wireless Communicating Networks

• Wireless communicating networks cover a broad area, including various technologies.
• The lecturer, Dr. Yousef Hamouda, provides contact information.
• Meeting times and discussions are available upon request through email.
• Students are expected to have mobile phones turned off during class.
• Noise and inappropriate interruptions are not permitted.
• Students should be on time; excessive tardiness (>10 mins) is not tolerated.
• Food and drinks are prohibited during class.
• Active learning is encouraged; ask questions and requests clarification when needed.

Supporting Information

• Information sources include lecture notes, textbooks, and additional online or printed resources.

Text Books

• Behrouz A. Forouzan's "DATA COMMUNICATIONS AND NETWORKING" (4th Edition, 2007) is a recommended text.
• Other suggested text books are also available, each with a specific focus on networking.

Assessment

• The assessment consists of exams and coursework, including research papers.
• The final exam contributes 50% to the final grade.
• Individual written coursework accounts for 50% of the grade.
• Two research papers (6 pages each) contribute toward the written coursework component.

Research Topic

• Subject areas for study include Wireless Sensor Networks (WSN), Zigbee, Bluetooth Low Energy (BLE), Low Power Wide Area Networks (LPWAN), Narrowband IoT (NB-IoT), WiFi, WiMax, LoRa, Wireless M-Bus, Free Space Optical (FSO), Satellite Communication, Near Field Communication (NFC), Radio Frequency Identification (RFID), Infrared (IR), Machine Learning, AI, and Security.

Computer Network

• Computer networks connect multiple computers together.
• Fixed devices include desktops (PCs) and workstations.
• Portable devices such as laptops, PDAs, mobile phones, and smartphones, are also part of the network.
• Network devices include hubs, switches, routers, and printers.
• Wireless access points, such as WLAN and Bluetooth APs, enable wireless connectivity.

Simple Computer Network

• Nodes are general-purpose computers, cell phones, PDAs, or network devices such as switches and routers.
• Links are physical connections between nodes, such as twisted-pair wire, coaxial cable, optical fiber, or free space (radio waves or microwaves).

Network Components

• Network components include links (fibers, coaxial cable), interfaces (Ethernet card, wireless card), and network devices (large router, computers).

Multi-Access vs. Point-to-Point Link

• Multi-access links use a shared medium, and require arbitration mechanisms, whereas point-to-point links operate on dedicated lines.
• Limitations of both approaches are relative to the number of involved adapters, and the difficulty in sending data to only one computer in the network.

Simplex vs Duplex

• Simplex communication is unidirectional (e.g., TV).
• Half-duplex communication is bidirectional but only one way at a time (e.g., police radio).
• Full-duplex communication is bidirectional and simultaneous (e.g., telephone).

Types of Networks

• Networks are categorized based on their geographic extent:
  • Wide Area Network (WAN): a geographically dispersed network.
  • Metropolitan Area Network (MAN): a network spanning a city or metropolitan area.
  • Local Area Network (LAN): a network in a confined area like a building.

LAN Topologies

• LAN topologies include tree, bus, ring, and star configurations.

Growth of the Internet

• Internet usage has grown rapidly over the last decade.
• Increased applications and users have led to greater reliance and connectivity.

The Internet

• The internet connects multiple computers globally.
• It's a network of networks, comprised of interconnected networks.

The Internet-2

• Millions of connected computing devices (hosts or end systems).
• Internet applications (like web browsers) run on interconnected networks.
• Communication links, e.g., fiber, copper, radio, and satellite.

The Internet (Routers)

• Routers forward data packets (chunks of data).
• Protocols control data sending and receiving (e.g., TCP, IP, HTTP, FTP).
• The internet is a hierarchical network.
• Public and private intranets contrast in accessibility.

The Internet (Interoperability)

• Multiple service providers contribute to the internet globally.
• Each network is independent; their interoperability relies on internet standards, such as IP and TCP.

Who Defines the Protocols?

• Protocols are defined by the Internet Engineering Task Force (IETF).
• The IETF website and RFCs (Requests for Comments) provide standards.

Network Structure

• Networks have edge (hosts, applications), core (routers-network of networks), and access (communication links) components.

Network Edge

• End systems (hosts) run applications (e.g., web, email).
• The client-server model involves clients requesting service from servers (e.g., web browsers and web servers).
• Peer-to-peer models (like file-sharing) minimize dedicated servers.

Network Core

• The network core is a mesh of interconnected routers.
• Circuit switching (like telephones) uses dedicated circuits per call.
• Packet switching divides data into packets for transmission over the network.

Circuit Switching

• Circuit switching dedicates resources (bandwidth, capacity) for a call, limiting its flexibility.
• It guarantees circuit-like performance, and requires call setup in advance.

Advantages of Circuit Switching

• Guaranteed bandwidth
• Predictable communication performance

Disadvantages of Circuit Switching

• Wasted bandwidth during periods of no data transmission.
• Cannot handle bursty traffic effectively.
• Unresponsive to dynamic data transmission needs; it's unable to accommodate diverse transmission needs effectively.
• Difficulty adapting to different transmission needs of users.

Packet Switching

• Packet switching divides data into smaller packets for transmission.
• All packets share network resources.
• Packets travel independently over the entire network.
• Forwarding is based on header information (e.g., addresses).
• Destination reconstructs the message.

Packet Switching (2)

• Best-effort delivery with the risk of packet loss, corruption, and out-of-order delivery.

Disadvantages of Packet Switching

• Variable delays due to varied packet sizes and routing paths.
• Overhead information for each packet (e.g., addressing, sequencing).

Access Networks

• Access networks connect end systems to the edge router, including residential, home, institutional, and mobile networks.

Access Networks (2)

• Access networks use various technologies (e.g., DSL, cable, fiber, cellular, WiFi, Ethernet, etc.) to connect end systems to the network.
• Different technologies and media (e.g., air interface, wired lines) facilitate data transmission based on local and regional connectivity.

Protocol Layers - Why Layering?

• Dividing tasks into independent layers.
• Establishing well-defined interfaces between layers.
• Dealing with complex systems (explaining the relationship between pieces).
• Specifying different functionalities in layers.
• Modularization aids maintenance and upgrades.
• Transparency of layer changes to other layers.

OSI Model

• Open Systems Interconnection (OSI) model, developed by ISO, defines seven layers.
• Each layer performs specific functions, using protocols.
• Each layer interacts with the layer directly above or below it.
• Layers process data received from the previous layer and send it to the next layer.

OSI Model (Specific Layers)

• Each layer in the OSI model has a specific role; the application, presentation, session, transport, network, data link, and physical layers. They handle protocols and services.

TCP/IP Protocol Stack

• The TCP/IP protocol stack is a layered model that defines the protocols used for internet communication.
• It correlates with the OSI model, but has fewer layers.
• The physical layer, data link layer, internet layer, transport layer, and application layer are its essential components.

TCP/IP Physical Layer

• Physical layer specifications include the characteristics of the transmission medium, nature of signals, data rate, distances, and other essential elements for transferring bits across communication channels.

TCP/IP Network Access Layer

• This layer handles communication between an end system and its attached network.
• Framing, addressing, and switching protocols (e.g., Ethernet) are crucial elements for functionality.

TCP/IP Internet Layer (IP)

• Internet Protocol (IP) manages routing tasks, allowing data transmission across interconnected networks.

TCP/IP Transport Layer

• Core protocols like TCP (reliable) and UDP (unreliable) allow the transport of data.

TCP/IP Application Layer

• Application layer protocols (e.g., FTP, HTTP, DNS, DHCP, SMTP, BitTorrent) support specific user applications.

TCP/IP Stack: Protocols (Summary)

• Application layer (defining protocols supporting applications).
• Transport layer (protocols responsible for communication between hosts, delivering data reliably or unreliably).
• Network layer (routing data in the network.)
• Link layer (connection between devices on a network.)

Layering & Headers

• Each layer adds headers and possibly trailers for control information.

Headers (Detailed)

• Headers provide layer-specific control information, such as addresses, sequencing, and other crucial data for different layers.

Encapsulation

• Data encapsulation is a crucial component in data transmission methods.

Example: HTTP Service

• HTTP illustrates how different network components work together in layers, from hosts and servers to routers and switches involving different protocols.

Delays in Packet-Switched Networks

• Processing delays account for tasks like checking bits and determining output links.
• Transmission delay depends on link bandwidth and packet length.
• Queuing delay results from waiting in queues at the output link.
• Propagation delay depends on signal transmission speed and the link length.
• The formula for total nodal delay incorporates these variables.

“Real” Internet Delays and Routes

• Shows data transmission delays for a long-distance Internet connection.
• Reveals the complex path data takes through nodes and networks.