Hub vs Switch vs Repeater | LAN Devices Comparison/differences

What is Repeater in Computer networking?

Repeater is physical layer device, it works on the physical layer of OSI model. Repeater are used to amplify signal and it is actually a signal regenerator. The repeater extend the length of the LAN segment, provide the long distance communication. The most typical application of the repeater is to connect two or more segments of the Ethernet cable, its purpose is to extend the length of the network and however extension is limited.Active hubs are example of repeaters. They are the cheapest way to connect two or more computers together. In modern networks we are using the wifi repeaters.

Repeaters can be connected to the same transmission medium of the same LAN and also may connect different kind of LAN transmission medium (for example: coaxial cable with Ethernet).

What is Hub in Computer networking?

Hub are physical layer device and provide common connection points for multiple devices on Ethernet.Hub is pure hardware device and there is no system software. Hubs mainly used to connect computers and other network terminal within LAN.
In Hub bandwidth is shared, only one device can send the data at a time, all other devices must have to wait, once the sending is finished then the bandwidth used by the other devices. Thus the hub is consider to a network collision domain.

Hubs cannot determine the destination of the packet and type, so it forward broadcast packets, and all devices send data as a broadcast to each interface, so hub is consider as multiple broadcast domain.

Switch in Computer networking?

Switch works at the data link layer (second layer) of OSI model. Switch breaks Ethernet segment into multiple collision domains, each port/interface on the switch is a collision domain so device connected to switch does not conflict with other communication interfaces.
Switch is more intelligent device as compare to hub it has software or operating system. Switch forward the packets on basis of MAC address. Whenever switch forward the packets to some device on network it also stores its MAC address into its MAC address table and once the MAC address table is build up, next time data will not be sent as broadcast but sent to interface, saving the interface bandwidth.
End point switches not only can record the MAC address table, you can also divide VLAN (Virtual LAN) to isolate the broadcast, but also inter VLAN communication you need a router.

Difference between Hub and Switch:

Hubs are the pure hardware for connecting network terminal and cannot break collision domains and broadcast domains.
Switch: with software system used to connect to the network terminals, able to break collision domains, but not split broadcast domains

Following table provide us the quick comparison of each Network device:

Device	OSI Layer	Transparent Or Protocol Aware?	Boundary	What It Understands
Repeater	Physical Layer (Layer-1)	Transparent	Amplify signal	Bits
Hub	Physical Layer (Layer-1)	Transparent	Amplify signal	Bits
Bridge	Datalink Layer (Layer-2)	Transparent	Collision domain	Frames
Switch	Datalink Layer (Layer-2)	Transparent	Collision domain	Frames
Router	Network Layer (Layer-3)	Aware	Broadcast domain	Packets
Layer 3 switch	Network Layer (Layer-3)	Aware	Broadcast domain	Packets