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What exactly does an ISP do?

networking isp

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3 replies to this topic

#1 DarkLordCthulhu


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Posted 28 February 2015 - 11:49 AM

First of all, I would like to apologize for yet another question that has nothing to do with programming.  I don't know of any good networking forums on the web.  I did register an account at networking-forum.com a few months back, only to have my first question rejected by the spam filter (which may have been either a bot or a human mod), despite it being a legitimate question about how to learn networking skills and not anything even remotely resembling spam.  So yeah, once again, the Internet has proven that CodeCall is the only decent forum for computer nerds aside from vintage-computer.com, Unix.com, and a few user/support groups.


Second of all, I would like to apologize for that off-topic rant.  I get pissy about stuff like this.


Third of all, I would like to apologize for the fact that my recent forum activity has consisted entirely of asking questions rather than contributing answers.  I haven't been as active on CodeCall as I would like, mostly just checking back every couple weeks or so to ask a question or post an update on my blog.  I've also found that in most cases I simply don't know the answers to the questions posted here, or they're just obvious beginner questions that have already been answered by ten different people.  There are other members here who are far more knowledgeable than I am who can provide far better answers than I can for technical questions.  As for me, I've had mostly questions lately, since I'm trying to learn about a lot of different areas right now.


tl;dr I apologize for being off-topic and not contributing answers.


Now on to my actual question.  I have realized that I don't actually understand what an ISP does.  I know what they do in layman's terms - that is, they provide Internet access to customers.  But why do you need an ISP for that?  Use of the Internet predates the first ISPs by at least a decade.  In pre-ISP days, you could connect to Usenet or to a BBS simply by hooking a modem to your computer and plugging it into the telephone line.  Logically speaking, it seems you could probably do the same thing today to connect to the World Wide Web.  Where does the ISP come in?  I don't get it.


I'm wondering if anyone can provide a technical explanation, or a link to a technical explanation, of the function of ISPs and how they operate.  I've tried the Wikipedia entry on ISPs, but it doesn't help.  I'm kind of at a loss here, as well as somewhat dumbstruck by my own ignorance of something so fundamental to the understanding of networks.  I've taken a networking class in college and I've read multiple books on Internet protocols, and yet I still don't know the basics.

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Posted 28 February 2015 - 01:26 PM

That's a good question.


The first thing to define is what the internet actually is. Basically its a number of a nodes connected together, with a connection between each node.


These node's might be computers; but actually its more likely to be routers/switches etc.


The connections; could be fiber, ethernet, wireless etc.


In practise, companies exist which look after this network and routes are organised into what is known as backbone's. If you do a google image search you see lots of diagrams showing the routes.


You then need access to these backbones - to be able to be on the internet. You could tap directly in (e.g. http://www.backbonec.../data-centres/)but that would be pretty expensive, and you have to tap where the backbone is. Since we don't tend to live at those locations, the ISP's tap into the back bone, then extend their network and deliver access to retail people via the phone/cable connections. 


So, no, you don't need ISP's. However in practise you do.

Edited by 0xDEADBEEF, 28 February 2015 - 01:31 PM.

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#3 WingedPanther73


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Posted 28 February 2015 - 03:18 PM

It depends on what you think the Internet actually IS. For most of us, it's a set of computers that are linked together by various types of network cables, routers, firewalls, etc to allow them to send messages back and forth with minimal delay. What an ISP does is connect your computer to all those others, using a variation on the same techniques that let your internal home network work :)

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#4 BlackRabbit


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Posted 28 February 2015 - 08:51 PM

All true. You can see it two ways:


- Internet services: like hosting, housing, virtual servers, VPNs, cloud storage/backup, etc

- Internet Provider: Which to make it simple, is a "last-mile service" providing you an effective flux of data through any kind of wire connection, usually your home phone line or optical fiber. ISP has no much sense for mobile devices and wifi because these are for mobile access than rather for a secure broadband, much less a SLA (service level agreement).


In short, if you just need to connect to internet to check your social media, then any kind of wifi will do.


If you need a strong connection for your server available every time with no decay in transmission capability, then you need an actual wired connection, and an SLA.

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