Web Architecture:
- Internet Service Providers (ISP)
- Web Hosting Services
- Domain Structure
- Domain Name Registrars
- World Wide Web
- Hardware
-Web
-Mail
Proxy Servers - Routers
- Software
-Browser
-email
- Transport and Addressing (TCP/IP)
Firstly, let me just make sure we know what the 'Internet' actually is...
The internet is a global computer network which provides a variety of information and communication facilities.
Is a network of computer networks and computers each with their own (unique) IP address and each uses the TCP/IP protocols.
It is not to be mistaken for the World Wide Web!
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Web Architecture:
Internet Service Providers (ISP)
Internet Service Providers are a business or organisation that offers its users access to the internet and related services. Not all, but many ISP's are telephone companies or other telecommunication providers; Who provide services such as internet access, internet transit, domain name registration, hosting and many others.
Web Hosting Services
A Web Hosting Service is a service that allows individuals and organisations to make their website accessible via the World Wide Web (internet).Web hosts are companies that provide space on a server as well as providing internet connectivity.
Domain Structure
Domain structures are identifiers and a locator systems in the internet. It maps IP addresses to URL names, specifies a mail server for the domain name and organizes the whole Internet system. It does this in such a way that information can be passed on and understood between computers and computers and between users and computers.
Domain Name Registrars
A Domain Name Registrar is a service that allows you to officially register your desired website domain name so that it is unique to you; meaning no one else can own it.
World Wide Web
Not to be confused with the INTERNET, The World Wide Web, (also know as WWW and 'the web') is a system of interlinked documents checked via the internet. With a web browser (Google, Chrome, Bing...) anyone can view web pages which may contain text, images, videos and other multimedia.
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Components:
Hardware
Hardware is the physical components that make up a computer system.
There are many different kinds of hardware that can be installed inside, and connected to the outside, of a computer.
Web server
A web server holds and provides web pages; serves web pages to clients and uses a HTTP protocol.
How does the web server know where to send the page back to?
Well, web servers may be integrated with other applications such as database management systems.
Web pages are also often uploaded via a FTP server.
How does the web server know where to send the page back to?
Well, web servers may be integrated with other applications such as database management systems.
Web pages are also often uploaded via a FTP server.
(E)mail servers
Mail servers are pretty much an electronic post-box for emails. It's run by ISP's or third parties such as gmail, so when a mail server receives an email for a client it is stored in the client's mail box. When the client accesses the email server, it validates the clients credentials and allows the client to download the messages in the clients box. Then when the client sends a message it first goes to the mail server which forwards it through to the internet.
Mail servers use protocols such as POP3 (receiving mail) and SMTP (sending mail) and also provides a spam filter. It can be accessed via a client (outlook mail server) or by a web page.
Proxy server
A proxy server is basically the security; It protects local networks from the internet and stores recently looked at web pages.
In more detail, a Proxy server is an intermediary between work station users and the internet. It needs a cache of recently accessed webpages and if the user requires a page in the cache it does not have to be downloaded again.
Proxy servers runs a firewall to filter data from inter-minimal machine, which means all the unnecessary data is removed which should reduce the number of hackings/hackers.
It allows cache to be shared between users and reduces the need to access the internet. It should also be invisible to workstation users!
Routers
A router is a device that receives packages or datagrams from one host (computer or router) and uses the destination IP address the packets contain to pass them, correctly formatted, to another host (PC or router).
In basic; Routers forward the packets to the next destination.
Explaining how a router works; The only way to explain this
so that it makes sense is if we use a roundabout as an example. The router is
the roundabout and the different ports are the different directions it could
go.
For example: the network number 12.0.0.0 arrives at the
router (roundabout), the router would see that it starts with the 12 and direct
it to port A. Another network number arrives at the router, this time the
number begins with a 195.. followed by other numbers. Again the router will see
that it begins with 195 and know that it needs to go down the port B. Same with
159.. going off to port C. However if the network number is anything beginning
with a 0.0.0.0 it’s the same as the roundabout’s directions saying it’s going
off to a different direction to specific places. In this case 0.0.0.0 is the
‘other directions’ route, which in router talk, goes off through port D.
The
same principal goes for the internet routers. However, this is classified more
as a hierarchy of routers, starting with local routers at the bottom like
schools and colleges. With every port D (other directions route) there is the
higher it goes to get you the information you need. So local routers will go up
to more localized systems such as counties; i.e. Sussex. If still not found,
the router will direct it up to regional routers like South East, South West
and then national routers. In some cases it’ll even go so far as up to
international routers.
Software
Software is a set of programs, procedures, functions...
The program software performs the function of the program it uses.
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Protocols: (TCP/IP)
A protocol is a set of rules for communications between devices; If all devices on the internet didn't use the same protocols, communication wouldn't be possible.
A protocol stack; his is when each set of rules uses the ones at a lower level, this means that the protocol from one layer could be replaced by another one.
A message is not sent across the internet whole; it is broken up into different blocks of data where extra information is added to each bloc according to the rules of each protocol.
An IP protocol defines the format of an IP packet; which contains the destination IP address. An IP packet contains a Time To Live value (TTL) which is decreased by 1 every time the packet goes through a router. When the TTL reaches 0, the packet is deleted; this is A) For safety reasons and B) so it doesn't sit aimlessly around the internet, or clog up anything.
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