Important Terms for Networking Devices

1. Collision Between Network Devices

• When two devices send some packet at the same time in the same Collision domain
• Occurs in One Way communication Devices that can either only send or receive packets, not both at the same time(like HUBs)

2. Uni-cast, Broad-cast & Multi-cast Unicast: One device sends to another device Broadcast: One Device sends to all other devices Multicast: One device sends to selected other devices

Types of Networking Devices

1. Network Interface(Card / Controller) [NIC]

• The main computer hardware component that connects a Computer to a network.
• Ethernet port connects other devices on a network
• PCI port is used to attach add-ons controller cards and other external devices

Types of NICs

• Wired NIC connects onto a network with an Ethernet or fiber optic cable.
• Wireless NIC (WNIC) comes with a small antenna, uses radio waves toconnect onto a Wi-Fi network / Bluetooth
• USB NIC overrides the computer's built-in wireless functionality, giving you a faster, more reliable connection to your available network signals through the USB port instead.

2. Repeater

• Signals over a long distance network(> 150 meters) Can get weaker and loss of data may occur
• A Repeater regenerates an incoming signal from the sender before re transmitting it to the receiver
• It acts on the physical layer(Layer 1 of OSI Model)

3. Hub

• It is a one way networking device, it acts basically like amulti-port repeater. (4-16 ports)
• It follows a [broadcast system](one to all) for sending packets, hence every node on the network receives the packet.
• HUBs don't allow two way communication and have collision problems(one action at a time)
• Operates on the physical layer(Layer 1 of OSI Model)

4. Bridge

• Basically a repeater, but sends packet from [source to destination using nodes' MAC addresses]
• Has a single input and single output port, thus making it a 2 port device.
• Operates on the Data Link layer(Layer 2 of OSI Model)

5. Switch

• A [multi-port bridge] that performs error check before forwarding data packets from source to destination via IP or MAC addresses
• Uses packet switching to send, receive or forward data packets or data frames over the network.
• Supports unicast, multicast as well as broadcast communications.
• Operates on the Data Link layer(Layer 2 of OSI Model)
• Unlike the HUB, a switch [supports two way communication](both receiving & sending can happen dynamically)

6. Gateway

• A network node that forms a [passage between two networks operating with different transmission protocols](connects multiples routers or switches)
• Can operate at Any layer of the OSI model (Most common type of gateways, the Network gateway operates at layer 3, i.e. network layer of the OSI)

Types of Gateways

• Network Gateway Interface between two dissimilar networks operating with different protocols.
• Cloud Storage, IOT, Internet Gateways

7. Router

• Receives, analyses, and forwards data packets among the connected computer networks.
• When a data packet arrives, the router:
  1. Inspects the destination address
  2. Consults its routing tables to decide the optimal route and
  3. Transfers the packet along this route.
• Operates at layer 3 or a network layer of the OSI model.

8. Modem

• Converts the digital data signals into analog data signals and vice versa
• Used over telephone lines, dial up connections, etc
• [Modulates and demodulates] analog carrier signals (sine waves) for encoding and decoding digital information for processing.