Network Devices: NIC and WiFi

Network Devices Overview

• Hardware devices connecting computers, printers, and other devices in a network.
• Also referred to as networking hardware.
• They ensure secure and accurate data transfer.
• Network devices are classified into different types for various networking purposes.

Network Interface Card (NIC)

• A NIC is essential for connecting machines to a network.
• Also known as an Ethernet card or network adapter.
• Operates at both the physical and data link layers.
• Enables computers to connect to an Ethernet network.
• It enables computers to connect to a LAN and communicate with other devices.
• Initially installed externally in older computers; is now typically an internal component.
• Each NIC is assigned a unique physical address by the manufacturer.
• Media Access Control (MAC) address serves as a unique identification number.
• Consists of 48 bits.
• It allows identification of thousands of network devices.

WiFi Card

• Enables devices to connect to a local network wirelessly.
• Uses WiFi technology, short for wireless fidelity.
• Contains radio and antenna.
• Commonly uses IEEE 802.11 standards (a/b/g/n/ac/ax).
• The 802.11ac standard is widely used.

WiFi Access Point (Hotspot)

• An area where WiFi to connect to a network is available.
• WiFi access points are necessary where wired networks are unavailable.
• Provides a physical area for a network.
• Provides Internet access, also known as a WiFi hotspot.
• Can be set up in homes, offices, or public places.
• Connects to a network through a wired connection.
• Connects to the internet-based network itself.
• Typically has a range of about 250 feet.
• The range can extend further in places like schools and universities.
• Only devices within range can connect to the network.
• May have a limit on the number of computing devices that can connect simultaneously.

Hub

• A physical layer device with multiple ports for connecting multiple computers in a LAN.
• Transmits data packets across the entire network, broadcasting data to all ports.
• Copies incoming signals and transmits them to another device.
• Duplicates the signal and transmits it to other devices, extending the network's range without needing a repeater.
• Insecure, as data packets are copied for all ports, including those that may not need it.
• Can become slow and congested due to the copying of data.
• Network switches are more commonly used due to the hubs limitations.

Switch

• More intelligent than a hub.
• Forwards data only to the intended recipient.
• Transfers data directly to the destination port.
• Examines packets for collisions and network errors before forwarding (packet filtering).
• Performs packet checking for collisions and network errors, known as packet sniffing.
• Maintains a list of MAC addresses associated with network devices.
• Prevents traffic overload in the LAN segment.
• Reduces collisions and increases network speed and performance compared to hubs.
• Switches operate at the data link layer.

Router

• Connects multiple networks together.
• Directs traffic between these networks.
• Determines how data can be sent between networks using IP addresses.
• Used to connect LANs to the Internet.
• Forwards data to other networks.
• Can repair and route data to another network.
• A WiFi router is a combination of a router and a modem.
• This converts the incoming broadband signal from an ISP.

Hub vs. Switch vs. Router

• Hub: Operates at the physical layer, broadcasts messages.
• Switch: Operates at the data link layer, forwards frames.
• Router: Operates at the network layer, forwards data packets.
• Hub: Connects devices in the same network over a short distance.
• Switch: Connects devices within the network, reducing network traffic.
• Router: Connects different networks (LAN to WAN).
• Hub: Does not perform routing.
• Switch and Router: Required for different network routing purposes.
• Hubs transmit messages through broadcasting, switches through frames, and routers through data packets.
• Hubs connect devices within the same network, switches connect devices within a local network, and routers connect different networks or to the Internet.
• Hubs do not maintain addressing tables, while switches and routers do.

Bridge

• Connects two or more LANs, operating at the data link layer.
• Can only forward traffic between identical networks.
• Data is sent only to ports using the same protocol.
• Forwards multiple frames simultaneously using MAC address filtering.
• Bridges learn MAC addresses and forward frames only to the destination port and can forward multiple frames at once.
• Enables connection of networks using different protocols, unlike a hub.
• Improves network performance compared to hubs due to directed forwarding.
• Used to create larger networks using mixed technologies.
• Bridges provide better performance than hubs.

Gateway

• A network node that serves as an access point to another network.
• Connects dissimilar networks (networks using different protocols).
• Connects different types of networks, regardless of their protocols.
• Enables communication between an enterprise network and the Internet.
• Used in both enterprise and internet settings to provide multiple connection to different networks.
• Can function as a proxy server to secure and administer the network.
• In a large enterprise, gateways are also used for proxy servers.

Repeater

• Needed to extend transmission distances so signals can go further while countering attenuation.
• Needed to extend transmission distances by amplifying signals.
• Amplifies and retransmits signals.
• Regenerate and retransmit signals.