This document provides information about common networking devices: - A hub physically connects devices on a local area network (LAN) but cannot detect MAC addresses or improve network performance. - A switch can detect specific connected devices by MAC address, perform error checking, and improve network performance compared to a hub. - A router operates at the network layer and is used to connect local area networks, detecting both IP addresses and MAC addresses. - A bridge and repeater both operate at the data link layer, with a bridge able to filter by MAC address and connect two LANs using the same protocol, while a repeater regenerates weak signals on the same network.

1. Hub, Switch, Router, Bridge, Repeater
Computer Networks
Lesson 3
Pranab Bandhu Nath
Senior Lecturer
CSE Department
City University, Dhaka
E-mail: bandhutuhin@gmail.com
web: www.ictdictionary.com
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2. HUB
• Hub Can Detect only Physical Pc but cant detect Mac Address
• A hub is a device to which all devices sharing a physical network can be a physically connected to
form a or “LAN”. Hubs do little more than enable the electrical currents from a computer sending
a packet to pass to all other devices connected to it.

3. Switch
• Switch can detect specific devices that are connected to it
• Switch can detect MAC address.
• Keeps Record of the MAC addresses of those devices.
• A switch is a data link layer device. The switch can perform error checking before
forwarding data.
• Improved network performance

4. Router
• Router Can Detect IP Address and Mac Address
• Router is mainly a Network Layer device.
• When a device in a Local Area Network needs to communicate with a device on another LAN, it
must send that traffic to a specialized device connected to the LAN called a “router”

5. Bridge
• A bridge operates at data link layer.
• A bridge is a repeater, with add on the functionality of filtering content by reading the MAC
addresses of source and destination.
• It is used for interconnecting two LANs working on the same protocol.
• It has a single input and single output port, thus making it a 2 port device.

6. Repeater
• A repeater operates at the physical layer.
• Its job is to regenerate the signal over the same network before the signal becomes too weak or
corrupted.
• When the signal becomes weak, they copy the signal bit by bit and regenerate it at the original
strength.
• It is a 2 port device.

7. Do you have any questions?