notes-shivam

01 Network devices

5 min read

1. Host

  • Definition: A host is any device connected to a network that can send, receive, or process data, that can request or serve data.
  • act as end-points in a network, either as clients (requesting data/services) or servers (providing data/services).
  • Examples: Computers, smartphones, tablets, printers, IoT devices

2. Client

  • Definition: A client is a device or program that requests services or resources from a server over a network.
  • Examples: Web browsers (Chrome, Firefox), email clients, file-sharing applications.
  • Role: Clients initiate communication by sending requests to servers. The server responds to these requests by providing data or services.

3. Server

  • Definition: A server is a device or software that provides services, resources, or data to other devices (clients) in a network.
  • Examples: Web servers, file servers, database servers, email servers.
  • Role: Servers host applications and services that clients connect to. They wait for client requests and respond with appropriate resources.

4. Repeater

  • Definition: A repeater is a networking device that amplifies or regenerates signals in a network to extend the transmission distance.
  • Role: A repeater is used in networks when the signal strength weakens over a long distance, like in wireless or wired networks. It picks up the weak signal, boosts it, and sends it out again.
  • Use Case: For example, in long-range Ethernet networks or Wi-Fi networks, repeaters extend the range of the signal, allowing data to travel longer distances.

5. Hub

  • Definition: A hub is a basic networking device that connects multiple devices in a network, often within a local area network (LAN).
  • It operates at the physical layer (Layer 1) of the OSI model.
  • It can be also called a multi-port repeater
  • Role: A hub takes data packets from one device and broadcasts them to all other connected devices.
  • It doesn’t have any intelligence to filter or route data, so all devices on the hub receive all the data.
  • Limitations: Hubs can lead to data collisions and security issues because all devices on the network see all traffic.
  • Use Case: Hubs are rarely used today, as switches have largely replaced them due to their limited functionality.

6. Bridge

  • Definition: A bridge is a device that connects and filters traffic between two or more network segments, helping to segment a larger network into smaller, more manageable pieces.
  • Role: A bridge operates at the data link layer (Layer 2) of the OSI model and helps reduce network traffic by only forwarding packets to the relevant segment.
  • Use Case: For instance, if a network has high traffic, a bridge can divide the network into segments, reducing congestion. It can also be used to connect networks with different physical media, like wired and wireless networks.

7. Switch

Definition :

  • A switch is a networking device that connects multiple devices within a network and facilliates communication, similar to a hub, but with more advanced features.
  • Switching : the process of moving data within a network

Role

  • It operates at the data link layer (Layer 2) but can also operate at the network layer (Layer 3) in the case of Layer 3 switches.
  • Role: A switch examines the MAC addresses of devices in the network and forwards data only to the device it is intended for, rather than broadcasting it to all devices like a hub.
  • This reduces congestion and improves network performance.
  • Use Case: Switches are commonly used in Ethernet networks and are essential for efficiently managing large networks, ensuring that data is only delivered to the intended recipient.

8. Router

Definition :

  • A networking device which facilliates communication among different networks.
  • A router is a device that routes data between different networks, such as a local network (LAN) and the internet (WAN).
  • Routing : the process of moving data between networks

Role

  • Routers learn which networks they are attatched to and those paths are called routes, stored in a routing table (contains all the networks the router knows)
  • IP address: Routers themselves have an IP address in each network they are attached to
  • Serves as a gateway for the hosts out of their own networks for the host 172.16.20.33 the gateway would be 172.16.20.1 (router’s IP address)
  • determines the best path for forwarding data packets between networks using IP addresses.
  • provide a traffic control points and features like Network Address Translation (NAT), firewall , and DHCP

Here the router has the IP address 172.16.20.1 in first network and 172.16.30.254 in the other network

Creates the heirarchy in networks and the internet

  • Routers operate at the network layer (Layer 3) of the OSI model.
  • Use Case: Routers are used to connect a home or office network to the internet.
  • They also help direct traffic between different departments in large enterprise networks or between a company’s internal network and remote locations.

Summary of Key Differences:

DeviceLayer (OSI Model)Primary Function
HostApplication LayerEnd-user devices that send/receive data
ClientApplication LayerRequests services/data from servers
ServerApplication LayerProvides services/data to clients
RepeaterPhysical LayerExtends signal range by amplifying/boosting signals
HubPhysical LayerBroadcasts data to all connected devices
BridgeData Link LayerConnects network segments and filters traffic
SwitchData Link LayerForwards data to specific devices (more efficient than hubs)
RouterNetwork LayerRoutes data between different networks/subnets

Each device plays a unique role in managing, controlling, and facilitating data transfer in a network. They are typically deployed together to create a functional and efficient network.

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