NETWORKING

Networking is a Department under the School of Computer Science. Courses focus on the interconnection of computing systems to share resources, and ultimately should provide an ever-increasing level of complexity in subject material, much as advancing classes in a traditional university do.
Networking is the practice of enabling and harnessing the transmission of data from one computer system to another. A crude analogy of a data network is pictured at right: two tin cans connected by a simple string. Note that what this basic analogy suggests holds true for actual implementations of data networks:

• The network exists merely as a medium for communications of some kind, across it
• A protocol of some form is needed to initiate and carry on conversations (this is not intrinsic to the network itself)
• The same protocol (a spoken language) can also be used with different media for the same purpose; different networks have different advantages and uses

A network may require one engineer to design it, another engineer to build it, and another engineer entirely to administer it. The skills needed for each stage in the process are related but not necessarily dependent; hence, Networking is interdisciplinary. The distinction between Networking and Computer Science in general is difficult to precisely define; it is better perhaps to consider that Networking grew out of Computer Science, because of a need to extend the existing capabilities of a computer (which includes data transmission) across large distances and with other unlike systems. However, an extensive background in Computer Science is not necessary to study or even practice Networking. A Network Engineer is a qualified individual who works with networks of some form, but the scope of that work and the skills required may be as diverse - even from one job to the next - as those of any scientist.

Networking is the practice of enabling and harnessing the transmission of data from one computer system to another, and can be divided into three categories:

• Connectivity Concepts - The principles and methods devices use to communicate over a network
• Mediums - The actual, physical method used to communicate.
• Administration - The process of maintaining a network.

THE INTERNET

The Internet is the worldwide "network of networks" that links millions of computers together via copper wires, fiber-optic cables, wireless connections, and other telecommunications channels. It is a massive network of networks, a networking infrastructure, forming a network in which any computer can communicate with any other computer as long as they are both connected to the Internet. Information that travels over the Internet does so via a variety of languages known as protocols.This publicly accessible network of interconnected computer networks communicate using a set of protocols and standards, the most basic of which are TCP/IP. TCP/IP consists of the Transmission Control Protocol in conjuntion with the Internet Protocol. Other protocols such as DHCP, DNS, FTP, HTTP, IRC, MIME, POP3, SMTP, SSH, TELNET, RTP and many more help hold the whole thing together.
This learning resource will look mostly at the technical aspects of the Internet, but may eventually cover social, economic, historical and other aspects.
A popular way to visualize the complexity of the Internet is to see it as a stack of layers known as the OSI model, short for Open Systems Interconnection model.

OSI Layers:
* Layer 7: Application Layer – the main interface for the user(s) to interact with the application and therefore the network
* Layer 6: Presentation Layer – transforms data to provide a standard interface for the Application layer
* Layer 5: Session Layer – controls the dialogues (sessions) between computers
* Layer 4: Transport Layer – provides transparent transfer of data between end users and machines
* Layer 3: Network Layer – provides the functional and procedural means of transferring variable length data sequences from a source to a destination via one or more networks
* Layer 2: Data Link Layer – provides the functional and procedural means to transfer data between network entities and to detect and possibly correct errors that may occur in the physical layer
* Layer 1: Physical Layer – defines all the electrical and physical specifications for devices and the communications media