Um, what does a router actually do? I just bought one and it turns out I need a modem to plug it into as well...

dhcp servers
nat devices
ppp clients

...

switches create networks
access points allow wireless connections to networks
routers connect different networks together
modems connect you to your ISP's network which leads to the greater internet

it's possible to have all these implemented as separate devices, but most mainstream "routers" have the switch and access point integrated

ISP's also offer all-in-one units with the modem built-in

>switches create networks
Switches break up collision domains.

Router routes things
Modems modulates or demodulates things
Switches switches things
Access Points help you access things
Ethernet ethers the net

A modem converts a signal from your ISP over coax/dsl/fiber to something you can plug your own network devices to. Usually people will attach a router to it so that they can share the network with multiple devices. Since the use case is pretty common, most ISPs offer a combo device that does both of these things.
You might want to buy your own router because like most things related to ISPs, their routers are probably kinda shitty and locked down.
To answer the original question, a typical router is nothing but a small, low powered computer that directs traffic to other devices. Networking is a very basic function of every computer and doesn't need a lot of power (most of the time).

>doesn't need a lot of power
Say that to my dual Xeon E5 10-core UTM 10-gigabit router

Overpowered.

a router is a gateway between networks
when your computer tries to communicate with another computer that isnt on your local network (the computers directly connected to the switch) the packet is sent out thru router/gateway. the router then checks to see if the destination host is in it’s local network in the external interface. if not, the packet is then sent to that router’s router. this continues until the packet eventually reaches a router who knows the route to the network of the host you’re trying to reach. then the packet is passed back down to the right host using the reverse process

t writes code for virtual routers

No, it can barely handle 10Gbit between two subnets from a single client-to-client file transfer.

It's the internet in a box. Take it with you anywhere!

You can even take it camping. All you need is a generator.
Trust me, would I lie to you?

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it creates the internet tube to your house.

Then you have bloated filtering running on it.

a router connects two network i.e. your home LAN and the ISP network, so when you want to Jow Forums you send traffic to your router which then forwards it to the ISP network who will forward it towards the server.

a modem convert one kind of signal to another i.e. a cable modem convert from cable signal to twisted pair signal.

when you sign up to an ISP for internet, they give you a 'router' which is a router with modem and a wifi ap and a switch all jumbled together.

Sounds like you need to return it. You should just be able to plug it in and get internet

Since the question has been answered, I'll just add if your ISP provides you a modem that works as a router and all your devices are wired connection, do that. If it also does Wi-Fi and you want to connect to the net that way, do NOT use it for that. They all suck. Connect that modem to a 3rd part router and use it as a wireless access point. Do NOT use both devices as routers. Let the modem act as your router/firewall. Trying to do both isn't going to make you more secure. It's just going to give you problems connecting to the net.

Modems are usually built into routers nowdays..

Hijacking this thread to ask a stupid question:
Other than data invisicaps, what the hell is stopping me from ditching broadband/modems/routers altogether and just using my phone as a hotspot at home? Wouldn't that save a lot of time, space and money? How come you never see more people doing that?

tell that to my mom.
she has two house phones leading into a modem, then another modem for internet connected via an extremely insecure router.
two modems, two phones, and a router. and no cellphone.
it's frustrating.

So what does a modem actually do? I haven't seen those since 2008.

Because mobile traffic is almost never cheaper than home internet.

they modulate high frequency signals and filter out noise into something your computer can understand, and then it converts signals from your computer to high frequency signals that your ISP backbone can understand on the other end

Data caps, which you can't ignore.

Modems bridge two different layer one types, so Ethernet to dialup/DSL/cable/fiber.

Is there any appreciable difference between the cheapest shit $20 tp-link router and high end shit like those spider gaming routers?

Better CPUs that can route more devices.

Not really if you install something like OpenWRT on it, so long as the specs are similar.

Thanks for the quick answer user. Major of my city are covered by MetroEthernet. So I guess the ISP runs the ethernet cable directly from their switches into our house. Nowadays they are ditching ME for GPON. So they hand you a box that convert fibre signal to ethernet. Pretty cool.

what this guy said normally a router (historically) routes packets from one LAN to another LAN. you'd use a switch or a hub to move packets inside a LAN. and a gateway (just a fancy term to connect from one type of medium to another - say ethernet to whatever the telecommunication firm uses - T1, OC-3, whatever) to connect to the internet.

now the box the ISP sells you (sometimes they call it "modem", sometimes "router", sometimes "gateway"), and the wi-fi box you buy at the store ("router") all do more than one thing at the time (hence the variety of names).
those "boxes" can move packets inside your home network, to other networks (when you build subnets inside your network), or the internet. they also include things like firewalls, dhcp servers, NAT all built in, sometimes also dns server and vpn server too.

true, but nice way to confuse OP.

modem is just modulator/demodulator. converts analog to digital signal and vice versa. this was a (very) relevant term in the days of dial-up, where the signal from the phone line was analog. it's not as relevant anymore, as most signals from ISPs nowadays are digital (fiber, dsl, even cable is going digital now, although there's still a lot of analog cable out there).
the term is still used colloquially to signify "that box that connects to your ISP", even though that's technically incorrect in many cases (fiber "modem" - really?)

It routes packets.

10/10 response, this definitely explains what a router "does" to tech illiterates such as OP

The router allows multiple devices to use a single modem for internet access.
It also gives you wifi.
You're thinking of a modem/router combo that ISPs like to give out. Those kind of suck, though, since the firmware on them is usually pretty basic and you cant port forward on some of them.

That's weird, my ISP's modem has always had 4 lan ports and I've gone from 128kbps to 100Mbps and through many modems in the last 18 years.

Worst answer so far.

Modems can have switches built into them. They are also often routers.
For example, an external 56k modem (or ADSL modem) that connects to your serial port or USB port is not a router. It has no network presence. To share that internet connection to a network your computer would act as the router.
When I got fibre in Japan I brought my own wireless router along so all I got was a fibre modem. It had no network presence even though it had a ethernet interface. You had to jam it into the router's WAN port and set it up as a PPPoE connection. In that case the fibre modem was not a router, but if I got one that had wireless or a switch built in then it would have also been a router.

a router is software which routes network packets between multiple networks, such as to and from an internal LAN and the internet (a WAN)
the boxes you commonly see are typically a combination of;
- a switch (if it has multiple LAN ports)
- an AP (if it supports WiFi)
- a modem (if it has an analog interface like over telephone/cable)
- router software (if it has both WAN and LAN ports)

>Ethernet ethers the net

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>a router is software which routes network packets between multiple networks
Doesn't need to be software, but you are correct that it routes packets between multiple (sub)networks.

yes, there really is. some of the cheapest routers with wifi will only have 2.4 ghz and 100mbit ethernet, you absolutely don't want that. if it's got 5 ghz and gigabit ethernet then it's probably fine, that's like a step up to $50-60 from $20. those routers that are $200-300 usually allow for higher wireless ac speeds than a router costing $50 would but it's mostly pointless to buy those things because phones and laptops and devices like that all have one antenna - if it's a brand new high-end phone or laptop then you may be lucky and find that it's got two. a $50-60ish router will handle that just fine. No phones or laptops have wifi cards with four antennas - so you'll never see the promised speed of a $300 wifi router unless you buy two of them and bridge them together.

basically don't buy a $20 router but if it's got gigabit ethernet and 5ghz wireless ac then it's probably just fine.

They spread your internet connection through wi-fi.

It pretty much does need to be software.
It's acting at layer 3, which means it's working on protocols instead of hardware. Technically you could say firmware but that's just software baked into a chip.

First of all, I would argue that firmware isn't software (it's in the name), but yeah, lets assume that it is for the sake of the discussion.

Being a router does not mean that you have to understand routing algorithms, it could simply be creating a static routing table and then forwarding IP packets based on this. Looking up a in table to determine interface to forward on is a fairly trivial hardware operation. Software only comes to play when you start involving routing algorithms, but that's not a requirement according to the definition of a router.

Also, the layer is irrelevant. There are deep-packet inspection (layer 5 and above) equipment that are implemented in ICs+firmware, and even the simplest network cards these days support TCP segment offloading (which is hardware) and checksum calculation in hardware.

For example, here's an application-level intrusion detection implemented on FPGAs, which I would arguably claim is hardware:

ieeexplore.ieee.org/document/6254301/

do not buy cheap MIPS and ARM routers, they are slow and crap out too quickly, make your own using large heatsinks on x86 CPUs, efficient PSUs that aren't wallwarts, and reliable server PCIe NICs

NIDS is significantly different to routing though. Routers need to be part of at least two networks, which means they need to be able to negotiate IP settings and almost always accept assigned IP settings from a user. There are software methods that could do all of this for you so you could practically drop a router onto the edge to two networks and it would start working, but that's getting into the higher level Cisco stuff, not really counting the home stuff which comes preassigned with IPs and DHCP server often already on.

That FPGA implementation is a support chip anyways, a way of offloading the filtering tasks onto a dedicated chip that'll do the matching job faster than straight up software, but it's still software that's running above it.

>Routers need to be part of at least two networks,
The only thing that differentiates a network from another is the subnet mask. Forwarding packets from one network to another is, as stated previously, just a matter of associating subnets with ports.

>which means they need to be able to negotiate IP settings and almost always accept assigned IP settings from a user.
IP is a stateless protocol, everything is contained in the header + options. If you have a mechanism for configuring an IP table (which can be done manually on most systems), there is no reason why the router couldn't be implemented in hardware.

It does what a layer 3 device is supposed to do.

There are you happy now?

lel

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>Datacaps
>No Ethernet
>Performance
>no Routing Protocols

you could, but where do you live that mobile data is anywhere near as cheap as home internet data?

Why does it seem like everyone on Jow Forums has their own router while I'm stuck with my ISP's shittier one?

because you haven't replaced it?
how have you gone so long without trying to do something on it and realized it doesn't support it?

>Um, what does a router actually do?

It...routes. It takes a single road(internet) and splits it into multiple paths. Some wired, some wireless. It’s not really different than a water main going through a neighborhood, getting split off at ever house.

Last I checked you can't replace a Verizon fios router with your own.

obviously not everyone uses that

But I do and I'm all that matters...lol

i'm not at all familiar with it, so i can't offer any suggestions
i'm only familiar with dialup and asdl, as that's what has been available to me

HOLY SHIT
>>>\reddit\

Most Yuropoor country.
Here, 50GB of 4G runs you 20€ without being engaged.