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Computer Network

Computer Network is essentially systems of interconnected computers and devices that communicate with each other for various purposes, such as sharing resources, exchanging data, or providing services.

HUB

Hub is a device that connects multiple devices in a network. 

It operates at the physical layer of the OSI model and essentially broadcasts data to all devices connected to it.

 Hubs are considered outdated technology and have been largely replaced by switches, which offer better performance and efficiency by only sending data to the intended recipient.

ROUTER

Router is a networking device that forwards data packets between computer networks.

 It operates at the network layer of the OSI model and is responsible for determining the best path for data to travel from the source to the destination across interconnected networks.

 Routers use routing tables and algorithms to make these decisions.

 Additionally, routers often include features such as firewall protection, network address translation (NAT), and DHCP services. They are essential components of modern computer networks, including the internet.


NETWORK LAYER

The network layer is the third layer in the OSI (Open Systems Interconnection) model of computer networking. 

It's responsible for the logical addressing and routing of data packets between different networks. 

This layer ensures that data packets are correctly routed from the source to the destination across multiple networks, regardless of their physical connections.


Key functions of the network layer include:


1. Logical addressing: Assigning logical addresses (such as IP addresses) to devices on a network to uniquely identify them.


2. Routing: Determining the optimal path for data packets to travel from the source to the destination across interconnected networks.


3. Packet forwarding: Forwarding data packets based on logical addresses and routing information.


4. Fragmentation and reassembly: Breaking down large data packets into smaller units (if necessary) for transmission and reassembling them at the destination.


The network layer plays a crucial role in ensuring efficient and reliable communication between devices in a network, regardless of their physical locations.

 Differentiate between Hub, Switch & router 

Feature HubSwitchRouter
Definition Connects multiple devices in a network and broadcasts incoming traffic to all connected devices.Connects multiple devices in a network and sends incoming traffic only to the intended recipient.Connects multiple networks together and routes traffic between them.
OperationOperates on the physical layer of the OSI model.Operates on the data link layer of the OSI model.Operates on the network layer of the OSI model.
Traffic ControlLacks traffic control, resulting in collisions and broadcast storms.Manages traffic using MAC addresses, resulting in a more efficient network.Manages traffic using IP addresses and routes data based on the destination network address.
BroadcastsBroadcasts data to all devices on the network, causing congestion and collisions.Broadcasts data only to the intended recipient, reducing network congestion.Uses routing tables to send data to the intended recipient, reducing network congestion.
SecurityProvides no security features, making it vulnerable to network attacks.Offers some security features, such as MAC filtering and VLANs.Provides advanced security features, such as firewall, VPN, and access control.
ExamplePassive hub, active hubEthernet switch, Gigabit switchWireless router, VPN router
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