If we
happen to be task oriented and think of a distributed application, then the
whole idea from the beginning has been to make distinct differentiation between
processing and communication jobs involved in the task. Processing is the job of the host computer
(and this computer could be both the client and the server) and communication
is the job for network infrastructures and the Internet.
Internet is
an open source system. An open source is
one, the architecture, design and implementation of which is not proprietary
(everyone can get to the source code).
That is these details are made public and are accessible to all. The idea is very high interoperability. If a developer of a system wishes for that
system to readily connect to a particular system then this is possible if
particulars of that system is not proprietary and is accessible to him, that is if that system is open source.
Collaboration
is also another underlying idea of open systems or open source. The idea is for the community to collaborate
to provide for better, faster, cheaper (mostly free) and more reliable products
that are accessible to all. When IT
people have access to the source code and they can modify and redistribute it,
it evolves.
Internet is open system. What other open systems can you name? |
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Even the
regulating body that regulates the Internet is open. The Internet Engineering Task Force (IETF) is
an open international community of technicians, designers, vendors, researchers
and operators that are concerned with the operation and development of Internet
and Internet technologies. This
organisation is open in that any interested individual can join but there is no
membership. IETF is not a corporation
and is merely a collection of seminars, meetings, and presentations.
Internet
could be described as the largest possible Wide Area Network. It is the interconnection between all the
Local Area Networks that connect to the Internet. It is the largest sharing of resources and
services in the world and it is these resources and services that are the main
focus and interest of Internet and not so much the infrastructure that enables
the delivery of them. Another words
delivery and architecture of this infrastructure is well hidden from the user
and all the user cares for is the interesting bits, that is
the information he asked for.
Just
like any other network, Internet could be conceptualised according to OSI model
of communication. There are however a
number of protocols within the OSI stack that are
predominantly designed for greater interoperability and provision of easier
connectivity. What this basically means
is that adhering to these standards is crucial for readily connecting to the
Internet and being an integral part of it.
In particular TCP/IP suite of protocols are the
most important. These are in fact two
sets of protocols. Transmission Control
Protocol (TCP) is a transmission layer protocol and Internet Protocol (IP) is a
network layer protocol.
What are the similarities and differences of
LAN/WAN based networks and Internet? |
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The are
many (1000s) regional ISPs. These
provide individuals and also companies access to the Internet. Examples of regional ISPs could be Freeserve, and AOL. There
are also those service providers, referred to as Backbone ISPs. These are not great in numbers and amount to
dozens and they operate the high speed networks. The regional ISPs have access to the Internet
through the BISPs.
The BISPs also provide companies with access
to the Internet. Examples of BISPs are At&T,
PSINet, and Cable and Wireless. Many regional and backbone ISPs interconnect and
exchange information at Network Access Points (NAPs). So Internet is a network of the NAPs, BISPs, ISPs, and on the
periphery we have the company networks and the individual users and personal servers. These are the entities on the periphery that
are the interesting parts of Internet as they hold the required information and
services.
Typically
an individual, wishing to connect to the Internet from home through a personal
computer would need a modem, a telephone line
connection and an account with his regional ISP. These regional ISPs also provide their
clients with value-added services such as Email, and Web space. A company LAN could connect to the Internet via
a regional or a backbone service provider.
Access to the internet and to the company resources are through a web
server and a security provision such as a Firewall. Corporate needs such as web-hosting and Email
services could also be outsourced from these ISPs. Organisations that have a high number of
users on a LAN would need a dedicated connection. ISPs could arrange a T1 connection, for which
a flat rate is usually charged. The
dedicated line is arranged by the ISP through the local telephone company. These ISPs are usually those with significant
backbone capacity and those have a direct connection to NAPs
are preferred. Each computer that is
connected to the Internet is allocated a unique address referred to as its IP
address and usually a domain name is mapped onto this IP address. It is through the IP address that computers
manage to locate the required resources.
Food for
thought: