CFB Final Exam: Computer Networks and Security

Network Fundamentals

• Underlying architectures must address four basic characteristics to meet user expectations: scalability, reliability, performance, and security.
• The OSI model consists of seven layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

OSI Model Layers

• Physical Layer: defines physical means of data transmission
• Data Link Layer: provides error-free transfer of data frames between nodes
• Network Layer: routes data between nodes on different networks
• Transport Layer: provides reliable data transfer between devices
• Session Layer: establishes, manages, and terminates connections
• Presentation Layer: translates data into a format understandable by the receiving device
• Application Layer: provides services and interfaces for applications to communicate

Data Link Layer Sublayers

• Media Access Control (MAC) sublayer: controls access to the network
• Logical Link Control (LLC) sublayer: provides error-free transfer of data frames

Network Topologies

• Physical WAN topologies: Point-to-Point, Point-to-Multipoint, and Hub-and-Spoke
• Logical topologies: Bus, Star, Ring, Mesh, and Tree

Migration Techniques

• Three categories: Phased Migration, Parallel Migration, and Big-Bang Migration

IPv4 vs IPv6

• IPv4: 32-bit address, limited address space, uses NAT
• IPv6: 128-bit address, increased address space, improved security

Malware

• Three types: Viruses, Worms, and Trojans

Firewalls

• Four types: Network-based Firewalls, Host-based Firewalls, Application-based Firewalls, and Stateful Firewalls

Network Layer Operations

• Four basic processes: Routing, Addressing, Congestion Control, and Fragmentation

Networking Terminology

• Latency: delay between sending and receiving data
• Bandwidth: amount of data transmitted per unit time
• Throughput: actual amount of data transferred
• Encoding: converting data into a suitable format
• Signaling: control information used to manage data transmission

Cables and Wireless Connections

• Types of cables: Coaxial, Twisted Pair, and Fiber Optic
• Characteristics of cables: bandwidth, distance, and interference
• Limitations of wireless connections: security, interference, and range

Communication Modes

• Half-Duplex: data transmission in both directions, but not simultaneously
• Full-Duplex: data transmission in both directions simultaneously

Remote Access Protocols

• Telnet: insecure, uses plain text, and uses TCP
• SSH: secure, uses encryption, and uses TCP

Application Layer Protocols

• DNS: translates domain names to IP addresses
• DHCP: dynamically assigns IP addresses to devices

IPv4 Network Transmission

• Three ways of transmission: Unicast, Multicast, and Broadcast

IPv4 vs IPv6 Transition

• IP vs Tunneling: IPv6 packets encapsulated in IPv4 packets for transmission

Transport Layer Protocols

• TCP: connection-oriented, reliable, and error-checked
• UDP: connectionless, fast, and error-tolerant