3.0 DTC 101

The Internet

3.1 Networks

A network is defined as “an interconnected or interrelated chain, group, or system.” Although the science of networks is several hundred years old, it is in the age of electric (high speed) communications that the study of the interaction and behavior of complex relational data emerges. Complex networks such as telecommunication networks, computer networks, cognitive networks, and social networks all share distinct characteristics and emergent behavior. Networks are made up of individual nodes and the links that connect these nodes. A node with a greater than average amount of links in the network, is called a hub and often has the role of linking other nodes. Because networks contain multiple and divergent pathways between nodes, they exhibit nonlinearity, decentralization, interconnectedness and interdependence.

In a random network, new nodes attach themselves to a random node in the network, creating an unpredictable branching structure. In a small-world network, a controlled mathemetical graph makes it so that any node can be reached from any other node in a small number of steps. In a scale-free network, new nodes attach to hubs —nodes with the most connection to the other nodes. A scale-free network has the tendency to grow by favoring the already more active nodes. For example, Google and Facebook have grown exponentially to be such dominant hubs on the web, because anyone who goes online will want to use the services that everyone else seems to be using. In a random network, a new node will link itself to just a random node. And in a small-world network, nodes follow strict algorithms for linking.

The network effect in scale-free networks favors the growth of already popular nodes. This can seem to result in "the rich getting richer." However, active hubs can be rejected if they fail as connectors or if a better more active hub emerges. MySpace lost its dominant role as an online social network, because Facebook had more to offer as a hub for social interaction. In this case, the network effect was negative for MySpace and positive for Facebook.

Networks favor decentralization and nonlinearity as opposed to hierarchy and narrative sequence. The internet, in its early days, was thought of as just another form of mass media. But as the internet grew, without a plan or centralized control, it became clear that this was another kind of medium altogether. A medium that grew community networks, networks of knowledge and created a "network culture." To understand the social and cultural impact of the Internet, the video below gives a sense of the "power of networks" in an increasingly complex world.

3.2 A Network of Networks

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The Internet grew out of the efforts to connect the local computer networks of remote research institutions; to build a “network of networks” for the sharing of data and scientific research. The funding for this initial work came from the Advanced Research Projects Agency of the US Department of Defense and the result was ARPANET.

Key Stages of Internet Growth

ARPANET: the first instance of what would later become the Internet. On October 29, 1969 the first message was sent from a computer at UCLA to one at Stanford University. ARPANET used packet-swiching to break messages into small units that could be distributed across networks and put back together at the desitination, a specific computer address or IP address.

A Packet Network: unlike the telephone system's circuit network, where each conversation has a dedicated circuit, information on the Internet is sent in standardized individual packets that are routed dynamically through a changing collection of networks. This makes for a robust and efficient system for delivering information across networks.

Internet Protocol: the Internet has a few rules and standards for how users interact in the network. One of these protocols is the Internet Protocol or IP, which defines packet structures that hold the data to be delivered across the Internet. IP also defines addressing methods to label packets with source and destination information. An IP address is a numerical label (such as 216.3.128.12) assigned to each device connected to a computer network. To be on the Internet, there must be a computer device with a specific address so that messages can be sent and recieved. IP addresses are managed globally by the Internet Assigned Numbers Authority (IANA) and IP registries responsible for assigning users in designated territories.

TCP/IP: Transmission Control Protocol or TCP, which works with Internet Protocol, is rule-bound standard for establishing and maintaining a network connection and the exchange of data. TCP with IP defines how computers send packets of data to each other.

Email: Electronic Mail or Email operates across the Internet. In the early 1980s, email systems required the author and the recipient to both be online at the same time. Today's email systems are based on a "store-and-forward model. Email servers accept, forward, deliver, and store messages. Users need to connect to the network for as long as it takes to send or receive messages. Unlike the simultaneity of telecommunications, exchange with email allows for instant, yet asynchronous exchange.

World Wide Web: with the creation of Hypertext Markup Language or HTML in 1989, Internet documents could link to each other. This linking created neworks of knowledge that are independent of the underling networks of hardware. The rapid growth of the Web, based on human language communication, emerges as a new network "on top" of the networks of computers. A user joins an Internet Service Provider or ISP to connect to the Internet, but joins a "kite flying" forum to connect with a like-minded community.

Networked Media: with growth of high-speed interent connections in the 2000s, media besides just data and text — images, sound files, video files, geolocation and VR data — travel the Internet as packets to mutiple destinations. This makes the reproduction and remediation of complex and multimodal ideas across a global network effortless and nearly instantaneous. Media becomes conversational. This socializing with and through media brings new layers of cultural networks on top of the Internet.

Internet of Things: as individual objects are embedded with computing devices with IP addresses, and are connected to the Internet, their data (such as geolocation) can be tracked and monitored and made available to a global network. Someone searching to purchase a type of bolt or a Ming Dynasty vase may get an exact location, pricing and description delivered with out human intervention.

Types of Networks on the Internet

Personal Area Network (PAN): a personal area network enables communication between computer devices near a person.

Local Area Network (LAN): a local network, for example a home or office network, connect computers via ethernet or WiFi that connects to a router that connects to an Internet Service Provider or ISP.

Wireless Local Area Network (WLAN): a wireless computer network links two or more devices using wireless communication to form a local area network.

Campus Area Network (CAN): a campus area network is made up of an interconnection of local area networks within a limited geographical area.

Metropolitan Area Network (MAN): a metropolitan area network (MAN) interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network

Wide Area Network (WAN): a computer network in which the computers connected may be far apart, generally having a radius of half a mile or more.

Storage-Area Network (SAN): is storage-area network is a specialized, high-speed network that provides network access to storage.

3.3 Free vs. Open Source

3.4 Unit Exercise: Seeing the Internet

1. Find the IP address of your computer.
2. Find your current Internet Service Provider or ISP.
3. Search a random Wikipedia page.
4. See live statistics of the Internet.
5. Look at live maps of marine traffic.
6. Visit a map that tracks wikipedia edits around the world in real time.
7. Visit random streetview.

3.5 Glossary

3.5 Bibliography