Networking Fundamentals, Components, Wireless Tech, and Encapsulation

Comprehensive practice flashcards covering network architecture, hardware components, wireless frequency bands, home routing protocols, network performance metrics, and protocol encapsulation models.

What is the definition of a computer network?

Two or more computing devices connected to share resources and communicate.

In the client-server model, what roles do the client and server play?

The client is the device or browser requesting a service (e.g., a laptop asking for a webpage), while the server is the system providing the service or resources (e.g., a Web Server).

How does a peer-to-peer (P2P) network operate, and when is it best used?

Devices connect directly to each other without a central server; it is ideal for small, simple setups like two laptops sharing files at home.

What memory trick represents the network scales in order of size?

P-L-W-M-W (PAN, LAN, WLAN, MAN, WAN).

What is the typical physical range and an example of a Personal Area Network (PAN)?

Around $1$ person ($\sim 1$ to $2\,\text{meters}$); examples include Bluetooth headphones and smartwatches.

What is the physical range and an example of a Local Area Network (LAN)?

Inside a single room, home, or building ($10$ to $100\,\text{meters}$); an example is a home office network using Ethernet.

What distinguishes a Wireless Local Area Network (WLAN) from a traditional LAN?

A WLAN is a Local Area Network that uses Wi-Fi instead of physical cables.

What is the physical range and an example of a Metropolitan Area Network (MAN)?

It spans an entire city or town ($5$ to $50\,\text{km}$); an example is city-wide municipal fiber loops.

What is the memory hook and primary function of a Network Interface Card (NIC)?

Memory hook: The "ID Card". Primary function: Connects a device to the network and holds the MAC address.

What is the memory hook and primary function of a network hub?

Memory hook: The "Loudspeaker" (Obsolete). Primary function: Repeats incoming data to every port, making it inefficient and insecure.

What is the memory hook and primary function of a network switch?

Memory hook: The "Smart Forwarder". Primary function: Connects devices inside a LAN and uses MAC addresses to send data only to the intended recipient.

What is the memory hook and primary function of a router?

Memory hook: The "Traffic Cop / Border Control". Primary function: Connects different networks together (e.g., your home network to the Internet) using IP addresses.

What is the memory hook and primary function of a Modem / ONT?

Memory hook: The "Translator". Primary function: Converts external ISP signals (coaxial/DSL or fiber light pulses) into digital signals your router can read.

What is the memory hook and primary function of an Access Point (AP)?

Memory hook: The "Wireless Bridge". Primary function: Bridges wireless devices into a wired network (provides Wi-Fi).

What are the trade-offs of the $2.4\,\text{GHz}$ Wi-Fi band?

It has longer range and better wall penetration, but slower speed and more interference (crowded with Bluetooth and microwaves).

What are the advantages and drawbacks of the $5\,\text{GHz}$ Wi-Fi band?

It offers faster speeds and less congestion, but has a shorter range and weaker wall penetration.

What are the key characteristics of the $6\,\text{GHz}$ Wi-Fi band introduced in Wi-Fi 6E/7?

It offers massive capacity and zero legacy interference, but has the shortest range.

What are the primary differences in range and usage between Bluetooth and NFC?

Bluetooth uses low power over a short range for personal peripherals (headsets, smartwatches), while NFC operates at extremely close range (almost touching) for tap-to-pay and access cards.

What is handover (handoff) in cellular networks?

The seamless process of a phone switching cell towers as the user moves.

What functions are combined inside a modern consumer multi-in-one home router?

Routing, Switching, Wi-Fi Access Point, Firewall, DHCP, and NAT.

What is the function of DHCP (Dynamic Host Configuration Protocol)?

It automatically hands out IP addresses to devices when they join the network so users do not have to type them manually.

What does NAT (Network Address Translation) do?

Allows many private devices at home to share a single public IP address given by an ISP.

Why is DNS (Domain Name System) called the "Phonebook of the Internet"?

It translates human-friendly names (such as google.com) into numeric IP addresses.

What is a Default Gateway?

The router's local IP address that a device uses to send traffic outside of its local network out to the Internet.

What are the four steps and commands of the network troubleshooting test order?

1. Local Config: Check your IP (ipconfig).
2. Router Reachable: Ping your router (ping 192.168.1.1).
3. Internet Reachable: Ping an external IP (ping 8.8.8.8).
4. Name Resolution: Test DNS (nslookup google.com).

How are bandwidth, throughput, latency, and goodput distinguished using network analogies?

Bandwidth is theoretical maximum capacity (number of highway lanes); throughput is actual data rate delivered (cars passing the tollbooth); latency (ping) is packet delay in milliseconds ($\text{ms}$, the highway speed limit); and goodput is usable application payload excluding headers and retransmissions.

What is encapsulation, and what is its key rule regarding layer outputs?

Encapsulation is the process where an application message travels down the protocol stack, and each lower layer adds its own header (and sometimes trailer); the key rule is that the output of the layer above becomes the payload for the layer below.

What mnemonic is used to remember the sequence of network data units from top to bottom?

"My Sister Drives Fast Bikes" representing: Message (Application) $\rightarrow$ Segment (Transport) $\rightarrow$ Datagram / Packet (Network) $\rightarrow$ Frame (Data Link) $\rightarrow$ Bits / Signals (Physical).

What occurs at each step of decapsulation at the receiver end?

The Physical layer reconstructs the received bit stream, Data Link processes the frame and passes the payload upward, Network processes the IP packet and extracts the transport unit, Transport uses the destination port to deliver data to the correct process, and Application receives usable data.

Why do both MAC addresses and IP addresses exist in computer networks?

MAC addresses (Physical Layer 2) support local-link delivery by identifying interfaces for switches, while IP addresses (Logical Layer 3) support logical delivery across interconnected networks for routers.

In the seven-layer email process, what actions occur at Layer 4 (Transport) and Layer 3 (Network)?

At Layer 4 (Transport), TCP breaks the email down into manageable chunks using port $443$. At Layer 3 (Network), IP addresses attach to the chunks so routers know where to send them.

In the seven-layer email process, what actions occur at Layer 2 (Data Link) and Layer 1 (Physical)?

At Layer 2 (Data Link), MAC addresses package data into Ethernet frames to move across the local room. At Layer 1 (Physical), electrical or light signals push the data through physical cables to the router.