What's in a router?

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Well i've seen a few stories of people turning old PCs into routers and changing the firmware/OS on an existing router. So i got to thinking - what's inside a router? Because it seems to me to be a specialised sort of computer. I found this image but it doesn't say much... i can see the main 'controller chip', a flash memory chip and some LAN controllers but that's about it.

And while i'm at it what exactly is a 'desktop switch'? Cheers :)
 
Essentially, it is a CPU (of some description, consumer routers aren't typically x86 instruction based), some RAM (for executing various commands such as NAT), some FLASH (for storing the system software), and the system software itself. Throw in a cheap switch which is interfaced with some kind of WAN port (be that an ADSL modem, or a dedicated eth port for a cable modem) and you have a typical consumer grade router.

This is why a PC can be easily ran as a router with software designed to do the job, such as pFsense.

Obviously there is more to it than that, but simply put that's about the gist of it.

This is why Cisco still see themselves as primarily a software company and not hardware, seeing as all the functionality and the work has mostly gone into the various softwares that run on their hardware, CatOS, IOS, AireOS, etc etc.
 
A bunch of bargain-basement parts shoved in a cheap case which doesn't effectively cool the components, flashed with some poorly written software and thrown on a shelf. More money than the cost of this hardware and software is then spent on a glossy box and marketing.
 
Most things like routers are essentially computers in thier own way. A router has a processor, some RAM and some non volitile memory and an operating system.
 
They could be a bit overhyped, they read and modify packets(NAT). And can add some firewall functionality.
 
They dont modify packets!
They inspect the header and either allow or drop packets based on the firewalls rules.
NAT functionality enables many computers to use one outside IP address

A slow router can have a massive impact on performance so put together your own hardware for the task if you have a lot of computers in your lan.

The products sold are for home and small business
Nothing beats a well designed network so read up before buying anything
 
Invictus said:
The products sold are for home and small business
Nothing beats a well designed network so read up before buying anything
Click to expand...
What products?

And no, nothing beats a well thought out network architecture. But a well thought out architecture doesn't include any switching or routing platforms available over the counter on the high street.

So that's kind of moot.
 
Where should one start reading in order to be able to assemble well thought out networks?

In the case of the more expensive routers then, the ones which sell for far more than a home user would be prepared to pay, is the hardware still relatively basic? What I'm getting at is whether or not a standard desktop pc running sufficiently competently written software could perform on a par with the enterprise solutions or not.
 
JonJ678 said:
Where should one start reading in order to be able to assemble well thought out networks?

In the case of the more expensive routers then, the ones which sell for far more than a home user would be prepared to pay, is the hardware still relatively basic? What I'm getting at is whether or not a standard desktop pc running sufficiently competently written software could perform on a par with the enterprise solutions or not.
Click to expand...

The point is, the opensource systems that you can source aren't anywhere near as well implemented as a decent enterprise router.

There is a reason that the cisco IOS has the reputation it has.
 
Also companies like Cisco have their own proprietary stuff running on their routers, for example Etherchannel (although other companies of similar grade routers usualy also have some form of port trunking technology themselves), EIGRP which I believe is a cisco proprietary routing protocol, but I'm unsure if they allow other companies to also use it.

You also have to remember when comparing a router to a PC running router software, is that a router is designed ground up for a single function, a PC is designed to be a general use machine, and even if a PC can pull off what a router can it most likely won't be anywhere near as efficient, reliable or small as a router.
 
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