Networking Fundamentals

Network Topologies and Devices

• A star topology connects each device to a central hub
• Routers connect multiple networks

Transmission Modes

• Full-duplex allows data to flow in both directions simultaneously
• Simplex data flow sends data in one direction only
• Half-duplex allows data to flow both ways, but only in one direction at a time

Network Types and Standards

• LAN stands for Local Area Network
• WAN stands for Wide Area Network
• 802.11a wireless standard operates at a 5 GHz frequency
• Wi-Fi uses radio waves

OSI Model

• The transport layer's main function is end-to-end communication and error handling
• The presentation layer is responsible for data compression
• The network layer is responsible for routing
• Encryption usually occurs in the presentation layer
• Switches operate at the data link layer of the OSI model

Protocols

• HTTPS is used for secure web browsing
• SMTP is used to send emails
• DHCP dynamically assigns IP addresses to devices on a network
• ARP maps IP addresses to MAC addresses
• DNS translates domain names to IP addresses
• HTTP is a protocol
• Protocols ensure that devices understand each other
• Protocols define the rules for data communication

Network Components and Concepts

• A subnet mask identifies the network portion of an IP address
• A VPN stands for Virtual Private Network
• A firewall filters incoming and outgoing network traffic
• A repeater amplifies and regenerates signals
• A modem converts digital signals to analog and vice versa
• Latency refers to the time it takes for a data packet to travel from source to destination
• The receiver is the person receiving the message

Key Network Criterion

• Performance is a key criterion of a network

Guided vs. Unguided Media

• Optical fiber is a transmission medium
• Optical fiber is the medium least affected by electrical noise
• Optical fiber cables offers the highest bandwidth
• Unguided media transmits signals through air
• Bluetooth is not a guided transmission medium

IP Addresses

• 10.0.0.1 is an example of a Class A IP address

Cables

• Twisted pair cable is most commonly used in telephone lines
• Optical fiber uses light signals to transmit data
• Shielded Twisted Pair (STP) is a networking cable type
• Coaxial cable is primarily used for television signals
• Twisted pair cable has the most susceptibility to EMI (electromagnetic interference)

Wireless Communication

• Satellites are used by GPS
• A major disadvantage of wireless communication is signal interference
• Radio waves are best used for long-distance wireless communication

Data Rate and Transmission

• Satellite connections have the slowest data rate
• Optical fiber is ideal for high-speed, long-distance communication
• Easy installation and mobility are the main advantages of wireless transmission
• Infrared transmission is typically used for remote controls
• Bandwidth describes the amount of data a system can handle
• Accuracy refers to the correctness of delivered data