Hardware

Provider

Network
ISP (Internet Service Provider)

  • It is the 'Internet Provider', for example: Vivo, Claro, Oi, etc.

Local Hardware

Ethernet

  • It is a technology used to connect devices via LAN or WAN, enabling communication between devices using protocols, which are a list of common rules of network language. Ethernet describes how network devices should format and transmit data so other devices inside the LAN (or other type of network) can recognize, receive and process the information. The 'Ethernet Cable' is the physical cable over which the data is transmitted. Compared to wireless connection technologies (WLAN / WiFi), Ethernet is typically less vulnerable to interruptions and provides a higher degree of network security and control. Because Ethernet-type connection requires the user to connect to the network using a physical cable, it makes unauthorized access to the network more difficult and prevents bandwidth hijacking, that is, prevents forced access to internet bandwidth and control.

Modem (Modulator + Demodulator)

  • The modem receives analog data and converts it to digital for use by the device (demodulate), while converting the digital signal to analog to be sent back to the ISP (modulate). Because of this, the modem is a fundamental device to establish any local communication with the ISP; the router on the other hand is optional. The modem alone cannot connect via WLAN, but it can connect via LAN, that is, the modem needs a router to send WiFi signal, but does not need a router for wired connections. It is possible that the device is a Modem/Router combo, having both modem and router functionalities. There are 2 types of modem:

    • 'Cable Modem': uses a 'Coaxial Cable' as input and the 'Ethernet Cable' as output.

    • 'DSL Modem': uses a 'Telephone Line Cable' as input and the 'Ethernet Cable' as output.

    • Explanatory video: PowerCert video .

WAN (Wide Area Network)

  • It is a network communication system that connects multiple devices across the globe. The 'WAN connection' is also called the 'Internet connection'. WAN communications are the largest and most expensive forms of networks available in the world. These connections are used in companies, schools, governments or by the public. The clients of these connections use them to communicate with any other user in the world, provided both have a WAN connection. The Internet itself can be considered a type of WAN. In other words, the difference between WAN and LAN is purely a matter of geographic scale.

  • Explanation and illustration of the differences between 'geographic scales of computer networks': Wikipedia section .

LAN (Local Area Network)

  • It is a network communication system related to local and wired connection. The 'LAN connection' is also called the 'Ethernet connection'.

HUB

  • It is a device that connects several other network devices via Ethernet cable. When one device sends information to the hub, all other devices connected to the hub receive that information. Any device connected to the hub can be both input and output; there is no filtering of devices or data. It works in a very simple 'non-intelligent' way, just copying the data and sending it to the rest of the devices, which causes slowdowns in the network; this makes them outdated and practically unused today. By definition, a HUB is a device that forwards data packets to all devices on a network.

Switch

  • It is a device that works similarly to a hub, but in an 'intelligent' way, storing the MAC address information of each device and only sending data to the device that is the intended destination, avoiding unnecessary traffic on the network that would cause internet speed slowdowns during the process. In short, both the hub and the switch have similar purposes, but the switch avoids unnecessary traffic, making it superior in many situations. A switch is normally used to increase the number of LAN ports of a router, allowing more wired connections to the network. That makes it considered a "cabling bridge" between devices on a network. A switch alone in a network does not have much purpose, since it needs some other device to assign an IP address to devices, such as a router. By definition, a switch is a device that forwards data packets to the appropriate destination on a network.

Types of Internet cables

  • Coaxial Cable (TV cable):

    • Can have slowdowns during 'peak hours' in the neighborhood, since the connection is shared across the region. It only needs to connect the cable to a modem to work.

  • DSL (Digital Subscriber Line) (phone cable):

    • It is tremendously superior to dial-up, although both use telephone line. Allows you to talk on the phone and access the internet at the same time. Generally offers slower plans than a coaxial cable connection, but it is a cheaper option and offers greater stability, because there is no sharing of cables in the neighborhood; each residence has its own line. It only needs to connect the cable to a modem to work. There are two types of DSL plans:

      • ADSL (Asymmetric Digital Subscriber Line): most common plan used in homes, where upload speed is significantly slower than download speed.

      • SDSL (Symmetric Digital Subscriber Line): plan used in businesses, where upload speed equals download speed.

      • VDSL (Very High Bit Rate Digital Subscriber Line): the fastest form of DSL, potentially up to 3x faster than ADSL. Because it uses copper wires, it only covers short distances.

  • Dial Connection (very old telephone cable):

    • An extremely ancient and slow cable technology. It did not even allow talking on the phone and accessing the internet at the same time.

  • Fiber (Optical Fiber): Fiber and Optical Fiber are the same thing. It is superior to all other options listed above. It has the best connection speed and can travel longer distances. It is also less  susceptible to electromagnetic interference compared to coaxial cable and DSL, because fiber uses light inside a glass fiber to transmit information, making it less vulnerable over long distances.

  • PowerCert video .

Types of Ethernet cable (e.g., Cat5, Cat5e, Cat6, Cat7)
QoS (Quality of Service)

  • It is sometimes also described as 'Media Prioritization'. It is used to prioritize bandwidth based on IP or MAC address, making some devices have priority. Priority is only considered if a higher-priority device than the first one is being used; otherwise nothing happens.

MAC (Media Access Control, also known as 'Physical Address')

  • It is the physical identifier of the device. You can find the MAC address by typing ipconfig /all  in CMD and looking for 'Physical Address' or 'MAC Address'.

WiFi

Router

  • It works similarly to a switch, but it is not only able to "read/interpret" MAC addresses, it also does that with devices' IP addresses. This allows the router to be the 'Gateway' of the network, enabling communication between networks. A router does not necessarily need to have a wireless connection (WiFi); it can have only LAN connections. In summary, a router is a device that contains the functionality of: router, switch, modem (optional), WAP (optional for wireless connections). By definition, a router is a device that forwards data packets to the appropriate destination on a network and connects multiple networks via IP address.

  • Good explanation: PowerCert video .

WiFi (Wireless Fidelity) or 'WiFi IEEE 802.11'

  • Both acronyms mean the same thing since WiFis are standardized using the 802.11 base standard. The IEEE acronym comes from the 'Institute of Electrical and Electronics Engineers' (IEEE), which initially developed the technology in 1997.

    • Table comparing all 'WiFi IEEE 802.11 protocols': Intel site , click on 'Wi-Fi IEEE 802.11 protocol summary'.

  • Dangers and vulnerabilities of public WiFi .

    • Solution: VPN only.

Wifi Channel Width

  • It is the "range" in which a device can connect with the router (this deduction might be wrong). Channel width is measured in MHz, usually ranging from 20MHz up to 160MHz. The wider the width, the greater the bandwidth, allowing more data traffic and resulting in higher internet speed, up to the maximum allowed by the internet plan. At the same time, the wider the width, the larger the "detection range" of other devices, which can worsen the connection if there are many devices nearby. It is usually useful to leave the channel selection option on 'automatic', since it dynamically assigns the best channel when multiple devices are accessing the router.

WPA / WPA2 / WPA3 (WiFi Protected Access)

  • It is a security protocol used to create an access password for the connection, encrypting and improving the security of the data between the user and the router. Normally this does not fully solve issues because there are easy-to-exploit vulnerabilities if the router password is shared with many people, such as in public routers. People commonly use WPA2 by default because it is more secure than WPA. WPA3 was released in July 2020, providing better protection against dictionary password permutation attacks and better encryption of individual user data; there has not been time for this technology to be fully implemented but it is certainly more secure than WPA2.

WLAN (Wireless LAN)

  • It is a network communication system related to local connection that uses the air as the transmission medium, i.e., using WiFi technologies.

Hotspot

  • Physical location where devices can access the internet via WiFi or WLAN.

WAP (Wireless Access Point)

  • It is considered a WiFi signal "extender", its functionality limited to connecting to a router and retransmitting the data it receives from the wired side in a wireless manner. It can be considered a "wireless bridge" between devices on a network. It is normally used only in companies or reasonably large places that need multiple retransmissions of the WiFi signal to cover the entire area, making several WAPs necessary in that case; using multiple WAPs instead of multiple routers is useful because it allows all network access to be managed by a single device (router).

WPS (WiFi Protected Setup)

  • It is used to connect to the router's WiFi by pressing a physical button on the router, without needing to type the WiFi password. It is known to be insecure and useless. To disable the option, one way is to 'disable the router PIN' or 'disable WPS'.

SSID (Service Set Identifier)

  • Refers to the network name, commonly used to refer to the name of the router's WiFi access point.