This is a very technical question. It’s hard to answer this in an ELI5 format.

A network is a bunch of computers connected. How they’re connected is called the “topology” of the network.

Imagine one group of computers connected in one “network”. Now, imagine a second network. These two computer networks can’t just talk to each other if you put a cable between them. They won’t know (generally speaking) how to talk to each other. A router is a device that spans two networks, and is a “gateway” that passes stuff from one network to another.

That’s why your home router is called a “router”. It connects the ISP’s incredibly complex network that runs outside with the little itty bitty network in your house.

A modem is short for “modulator/demodulator”. That used to make more sense when “home modems” were devices which “sang notes” on the public telephone networks. The modulation was the “singing”, the “demodulation” was the “hearing” of the “notes” and interpreting it as data. Today, “modems” decode other types of signals, because often the type of signal from the ISP’s incredibly complex network is not the same kind of network in your house, nor is it the same “song and notes” from phone-based networks. So, your home router will also have a modem inside.

“Home routers” is a huge misnomer. It’s a gigantic smashing of all kinds of network devices bundled together into one appliance.

A “bridge” connects two networks, as well, like a router, except that it’s “more basic”, in that the two networks it connects become one bigger network. This is a technical distinction that’s hard to understand without a lot more detail. You will almost never encounter a bridge.

An “access point” almost always means “wireless access point”. It’s what allows your non-wired devices to talk to your network. In the past, these were separate things. But, in your home router, they will add that functionality all into the same box.

A switch and hub are similar. They are the “switchboard”, and allow computers to connect, forming the “network”. Again, this would be another separate device, but your home router has a switch built-in.

You’re mixing together wired terminology with wireless terminology, and that makes it harder to talk about. An AP (access point) is almost always referring to a wireless AP.

A “transceiver” is short for “transmitter/receiver”. Anything qualifies here. A modem qualifies. A wireless AP qualifies. A tin can connected to another tin can by a string qualifies. Your head qualifies (mouth makes sounds, ear hears sounds, brain does all the computational work). Any networked device must have some kind of transceiver; otherwise, it turns into a black box.

A “repeater” is exactly what it sounds like. It’s a transceiver that hears something, and then shouts it again. Imagine you’re trying to get your dad’s attention. But he’s outside. But your mom is in the kitchen. So, if she hears you yelling for your dad, she can then yell your command, and your dad might her yelling because she’s closer. Repeaters can be wired or wireless, although in most contexts, it’s meant to be wireless.

Range extenders are just repeaters, and almost always refer to wireless repeaters.

So, your home “router” does a lot of stuff in one box. A more complex network, say, with hundreds or thousand of hosts is going to need that stuff broken up into lots of separate boxes, for performance and management and security reasons.

If you want diagrams, I charge $225/hour to my corporate clients. Or, just go back to wikipedia/Google with these basic definitions, and try to work it from there.

a) For an ELI5, this is like asking for a full course in the "basics" of networking. Too much

b) It is technical. There is no way around it. It is like asking for a lesson in quantum mechanics without referencing physics. Not really meaningfully possible.

c) There are logical functions (translation of symbols/information) and physical hardware and then actual products (which incorporate a variety of functions and physical hardware). Think of it as a home address (logical/symbolic) vs the home (physical) and the postal service (a combination of using logical function and physical to provide a service). Without a clear appreciation of the differences (again technical), it would be hard to explain all the things you asked.

A starting point might be the OSI model to understand the conceptual framework of networking and communications. Then the various functionalities etc will make sense.

Router: Routes packets at the IP level.

Switch: Routes packets at the layer 2/MAC address level.

So a packet going out gets to a router, the router decides by IP address where that packet needs to go. If that IP address is "local" to the router, that is in a subnet the router has ownership of, it then uses switching to send the packet to the destination. Most modern routers have some switching capability, and most switches have some routing capability.

Hubs: Really dumb switches. A switch will keep track of connected devices, so if a packet is going to destination MAC aaaa.bbbb.cccc.dddd, it knows that MAC is on port 7 and sends it to that port. A hub does not keep track of such things and just sends the packet to every connected port. There may be some use cases for hubs still, but generally they should be avoided.

Bridge: generally a point to point link of some kind. For example, if you have two office buildings, the main one has the main network, but the second one needs to connect but you can't run any sort of standard ethernet arrangement, you might set up some sort of point-to-point wireless bridge connection.

Modem: Changes signal type. For example, cable internet does not use ethernet. So the cable modem is what changes the ethernet packets to the DOCSIS protocol on the cable coax.

Access Point: WiFi. Is the communication point for end devices using WiFi to talk to the network. Wireless broadcast, so arguably more of a hub than a switch in such terms.

Transceiver: The physical component in a router or switch that is turning the packets into flashes of light on the fiber line.

Repeater: If your signal has to go a long distance on the wire, it may not be strong enough to make it. So a repeater will just take the signal coming in and blast it out the other. The bonfires between Rohan and Gondor are repeaters.

Range Extender: I generally hear this with WiFi, essentially trying to do the same thing as a repeater, but it's sometimes a little more complicated since WiFi is broadcast radio.

so basically, there are devices that

1. repeats traffic it gets, ie it broadcasts to everyone connected to it, and also used for extending ranges. ie the repeaters and hubs. and range extenders for wireless.
2. devices that routes traffic to where it needs to go, ie only the specific device connected gets the traffic. ie switches, and access points for wireless.
3. devices that connect networks together, ie a local area network to a wide area network or two different wide area networks. ie routers
4. devices that converts one signal format to another signal format, ie analog to digital or digital to analog or coax to wifi, or whatever. . ie modems and transceivers

so basically using the postal service analogy. your post office is a router. all your mail goes through your post office. mail intended for an address not serviced by your post office is delivered to another post office (and that post office figures out where it needs to go). the mail delivery man is like the switch. they connect to your post office (router) and deliver the mail to your door. now a days, hubs/repeaters are typically not used anymore because that's like everyone in your post office delivery area getting everyone's else's mail as well, but you just throw away mail not intended for you.

Router vs Modem vs Access Point: A router is a device that forwards data packets between computer networks. It can also act as a firewall to protect your network from malicious activity. A modem is a device that modulates and demodulates signals for data transmission over telephone lines or other communication mediums. An access point is a device that allows wireless devices to connect to a wired network using Wi-Fi, Bluetooth, or similar technology. Switch vs Bridge vs Hub

Router: A router is a device that forwards data packets between computer networks. It is connected to two or more networks, such as the Internet and a local area network (LAN). Routers use headers and forwarding tables to determine the best path for forwarding the packets, and they use protocols such as ICMP to communicate with each other and configure the best route between any two hosts. Modem: A modem is a device that modulates an analog signal to encode digital information,