Been reading, got questions.

qwerty_face

Hi all,

I was reading Yeung and Wong's Network Infrastructure Security (2009) earlier on, specifically the introductory chapter. I found the discussion on the structure of the internet interesting. It has left me with some questions that I have previously wondered about but not up until now sought answers for.

Before I continue, do I have the following correct?

• ISP's own a network to which they allow access as a service [to clients]. Am I correct then by saying that you buy into their LAN?
• ISP's have Points of Presence (POPs) around the country. These POPs are networked via a low latency, high speed back-bone, i.e. fibre. When you sign up for internet service, you connect through the ISP's POP in your area. Correct?
• To reach a machine (server or client) that uses a connection with a different ISP an Internet Exchange Point (IXP, or Network Access Point (NAP)) makes this possible.

So you have:

Client** -> POP (which is owned by an ISP) -> IXP.

**be it a business or single person.

Examples of IXPs are listed at: European Internet Exchange Association (Euro-IX)

My questions are:

1. Let's say that business-A has the basic, stock requirements for a LAN, i.e. a couple of switches, perhaps a handful of routers, some servers, a firewall (by the way I am still learning the ropes here!). In terms of the technology, what is it that would differentiate business-A's hardware to say the ISP's side? Just more intermediary devices of higher spec (and price)? What specifically?
   
2. What technologies do POPs use?
3. What form does a POP take? What is it?
   
4. What technology is behind an IXP?
5. What form does an IXP take? I know that LINX (https://www.linx.net/) at London Docklands is an IXP, but apart from the look of the building it tells me nothing of the form.
   
6. Yeung & Wong generalise ISP's as: "a kind of network" (p. 3). What do you think they mean when they say a kind of network?
   
7. Where does a MAN and GAN fit into this?
   
8. Where do data centres come into the mix? What are the types of D/C's, e.g. I know that a global organisation may build their own D/C to house its own servers, but do some D/C's house POPs?
   
9. In terms of the data centre industry, what is "colocation"?
10. Again, in the D/C industry what is a "carrier"? And what does "carrier neutral" mean exactly?
    
11. What is an Access Level, National and I'national ISP? What differentiates them (i.e. in technology, form, business)? Where do the terms tier 1, 2, and 3 ISP's fit into this?
    
12. Where do the following companies fit:-
    • British Telecom (tier 1 ISP? I'national ISP?)
    • AT&T (I'national ISP?)
    • Verizon
    • TalkTalk (National ISP? Tier 2?)
    • Virgin Media
    • Zen Internet (Access Level ISP? Tier 3?)
    • Plusnet (Access Level ISP?)
    • Level 3 Communications (I'national, tier 1 ISP?)
    • Interoute Communications (I'national, tier 1 ISP?)
    • Tinet (I'national, tier 1 ISP?)

Many thanks for your input in advance.