Can someone explain me the difference between those three devices?
In: 1512
Imagine you’re in a room full of people, all chatting away with eachother. There’s someone specific with whom you want to have a conversation.
**Hub**: gets everyone in the room to take turns talking so when it’s your turn you can talk to the person in the corner without being interrupted. Everyone else has to wait for their turn. Sometimes two people try to talk an once so it’s a little more noisy and awkward but it can work to have a conversation.
**Switch**: gets some sets of tin cans on string and quickly _switches_ them around between people so you and the guy in the corner can have a private conversation without worrying about the other people talking.
**Router**: is a person standing in the doorway. You only talk to them if you need someone who’s in another room. They’ve got the number in their contacts for the person you want and they call them up then hand you the phone while you stay in your room.
Think of it like sending mail
Hub: I can’t read so I send a copy of the letter to every house
Switch: I can read but only know this neighborhood so I send the letter from one house to the house it needs to go to
Router: I can read and know the addresses in other neighborhoods so I can send the letter from one house to another in any neighborhood I know about
Ok let’s assume a single device is a room, then a hub is a long hallway connecting all rooms. A switch is having a receptionist like in a hotel in front of the hallway and allowing you only to reach the room you asked for. A router is now the tour guide guiding you through town and into the different hotels or houses were you want to go.
A switch is kind of like a highway interchange and the router is part of town you are trying to get to.
an example of when you need to know the differences when setting up a home network: modem brings internet into the house. I want to split the internet and send a hard wire to my nearby entertainment system with TV, xbox, roku whatever, but i also need to send the internet to my wifi router thats on the other side of the house. I could plug in a switch after the modem, send one cat5 to the wifi and send another cable the entertainment system, plug in a hub and connect all the devices. great everything has internet, problem is I no longer can broadcast from my phone to the TV, the entertainment system and wireless are on different networks.
Now take the same setup but swap the switch coming out the modem to a router, bam, set the wifi router to AP mode and everything talks to each other and works.
Hubs are also called repeaters if they actually resend the signal instead of literally just splitting it to multiple ports.
Hubs are generally dead in the consumer space because switches are the same price and better for almost all use cases. In industrial spaces, hubs still exist because they have essentially zero latency and jitter, which is very good for deterministic Ethernet protocols used by PLCs (Powerlink, EtherCAT, Profinet IRT, SercosIII, Veran, etc.). Many of those protocols are poll and response based too, so everything is a broadcast, eliminating any benefit of a switch. However newer switches are now fast enough that they will work in such applications, so even in industrial spaces, hubs are becoming more rare.
Hub: walkie talkies connectivity
Switch: in building phone system connectivity
Router: Phone lines to the rest of the world connectivity
hub is layer 1. think of it as a repeater. any data that hits one port, is repeated on all other ports
switch is layer 2. it has some smarts
when data hits a port, the switch reads the hardware address (Mac address) and only forwards data to the port that has that destination
router is layer 3. it reads ip addresses.
so when data hits a port, it reads the destination ip, and forwards data to only that appropriate port
So let’s say you have a hose. If there’s a switch at the end the water flows to each port and if it’s for you you drink it or if you want to send water you send it and everyone else can see it. If two people try to send water at the same time everyone gets confused and you have to try again.
A switch is like a hub but each port has address so when you send something it goes where you want it.
A router is for changing water between houses and different hoses.
You’re staying in a high-rise hotel, and you want to send some mail.
You take your letter to the concierge and tell them ‘send this to my brother. Here’s the last address I had for him.’
The concierge looks at the address – strangely, its here in the hotel. So he ROUTES it to the guest services person on the appropriate floor. The guest services person has a quick flash card of the name of everyone staying on the floor and what room they’re in. they SWITCH over to that room and knock on the door to deliver the letter, and then leave, not knowing what’s going on just inside.
In reality, your brother’s room is a party HUB – 20 people all living in the same room, communinally using the same resources. the door is too tight for them all to leave at the same time, so they have to take turns.
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