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Transcript
SOCIAL WEB MEDIA Course Introduction and Technical/Conceptual Foundations lecture based on: Navigating the Internet - Smith, Gibbs, McFedries Pocket Guides to the Internet – Veljkov Protocol (ch 1) – Galloway Wikipedia entries BASIC TERMS BASIC TERMS INTERNET WORLD WIDE WEB PROTOCOL TCP/IP IP ADDRESS DNS INTERNET or WEB? The Internet is a worldwide, publicly accessible series of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP) (Wikipedia) “A worldwide network of networks” (Veljkov p1) The World Wide Web (WWW) ...a system of interlinked hypertext documents accessed via the Internet. (Wikipedia) Email ? instant messaging ? (IRC, Jabber, etc) Facebook chat ? Usenet ? PROTOCOL general definition “agreed-upon methods of communication used by computers and, for that matter, by people.” (Smith p6) CULTURAL PROTOCOLS telephone call protocol bank line protocol grocery store line protocol classroom protocol In a formal meeting... “someone chairs the meeting, states its objectives... invites people to speak. When each person finishes speaking, control returns to the chair.” ways for handling interjections error conditions (Smith p6) for networked computers... which computer begins communication how replies are handled how will data be represented how will errors be handled TCP/IP two protocols... Transmission Control Protocol Internet Protocol protocol suites or protocol stacks lowest level to highest level lowest level: basic functions... receiving pulses of electricity from the communications medium Application layer Transport layer Internet layer Link layer Application layer (content) Transport layer (makes sure data arrives correctly – a social layer) Internet layer (actual movement of data from one place to another) Link layer (hardware-specific) Application layer (content) Telnet, FTP, HTTP Transport layer (makes sure data arrives correctly – a social layer) TCP, UDP Internet layer (actual movement of data from one place to another) IP & ICMP Link layer (hardware-specific) Compare to telephone call “protocols” conversation – (application layer) “Are you still there?” - (transport layer) “Can you repeat that?” - (transport layer) “Hi, this is...” “OK – Bye!” (transport layer - establishing and closing the connection) phone switching/routing (analogous to Internet layer) physical phone or fiber optic lines (link layer/hardware layer) Internet Protocol Developed to enable different local area networks to communicate with each other Has become the basis for connecting computers around the world together over the Internet TCP/IP IP = breaking up data and sending it TCP = make sure data arrives intact error correction is the responsibility of TCP routing is the responsibility of IP Data Transmission consists of sending/receiving streams of zeros and ones along the network connection Two Types of Information: Application data The information one computer attempts to send to another Network protocol data Describes how to reach the intended computer Describes how to check for errors in the transmission Data must be marked with a destination address IP ADDRESS In IP the destination address is 4 bytes (each byte is a number 0-255) example: 64.233.167.104 http://64.233.167.104/ To be able to accommodate more devices, IP addresses will be extended to sixteen bytes DNS Domain Name System resolves names “www.rhizome.org” into IP addresses 206.252.131.211 When a computer wants to request data from a domain name: It asks the DNS for the numeric Internet Address It includes the numeric address with the request for data Domain Name Servers distributed Domain Name System inverted tree structure decentralized hierarchy . (root) _____________|__________ | | | | .org .com .net .edu | | google buffalo | | | images www mediastudy to resolve the numerical address for mediastudy.buffalo.edu first a request goes to a root nameserver to find out where the appropriate top level domain server (.edu) is, then that server is queried as to where the host (buffalo) is, then the host is queried for the address of the actual computer in question (mediastudy) Each server only has info about the area directly below it in the hierarchy. Decentralized network model. Protocols TCP/IP peer-to-peer non-hierarchical distributed DNS hierarchical decentralized FLOW IP breaks large chunks of data up into more manageable packets Each packet is delivered separately Each packet in a larger transmission may be sent by a different route Packets The are numbered recipient reassembles the data Internet Protocol (IP) does not notify the sender if data is lost or garbled This is the job of a higher level protocol Transmission Control Protocol (TCP) The most commonly used Internet services use TCP with IP (TCP/IP) Attempt Try to deliver the data again if there are failures Notify the sender whether or not the attempt was successful PART 2: “The emergence of distributed networks is part of a larger shift in social life. [...] a movement away from central bureaucracies and vertical hierarchies toward a broad network of autonomous social actors.” - Galloway PART 2: “The emergence of distributed networks is part of a larger shift in social life. [...] a movement away from central bureaucracies and vertical hierarchies toward a broad network of autonomous social actors.” - Galloway PART 2: NETWORK TOPOLOGIES CENTRALIZED DECENTRALIZED DISTRIBUTED HUBS NODES HIERARCHIES RHIZOME [[clip: Apple Macintosh 1984 ad]] changes in workplace teams/outsourcing/consulting etc. Protocol “a set of guidelines or rules” (Wikipedia) Uses of term protocol: military chain of command, hierarchy Internet flexible, distributed, resistive of hierarchy Network Topologies Network models Centralized Decentralized Distributed discuss in terms of hubs and nodes... Image: Rand Corporation Cold War origins of Internet* (*specifics are open to debate) two images: nuclear attack Internet Two images: nuclear attack “highly energetic, dominating, centralized” Internet “non-centralized, non-dominating, nonhostile” (Galloway) Image: Rand Corporation centralized networks: hierarchical a single authoritative hub “top-down management” US judicial system Bentham's Panopticon (as discussed by Foucault) decentralized networks: network diagram of the modern era multiple hubs w/ dependent nodes airline system (airline hubs) university departments distributed networks: no central hubs no radial nodes each entity is autonomous Internet freeway system Many paths to a destination freeway system if 90 is closed use another route “The emergence of distributed networks is part of a larger shift in social life. [...] a movement away from central bureaucracies and vertical hierarchies toward a broad network of autonomous social actors.” “The emergence of distributed networks is part of a larger shift in social life. [...] a movement away from central bureaucracies and vertical hierarchies toward a broad network of autonomous social actors.” - Galloway Gilles Deleuze and Felix Guattari metaphors: arborescent tree-like structure directional rhizomatic root network (ginger) multiple, non-hierarchical image: Wikipedia “What was once protocol's primary liability in its former military context – the autonomous agent who does not listen to the chain of command – is now its primary constituent in the civil context.” (Galloway p38) Classical era sovereign central control Classical era sovereign central control Modern era bureaucracy decentralized control Classical era sovereign central control Modern era bureaucracy decentralized control Now ??? How it works... materiality of the Internet host computers clients (receiver of information) servers (sender of information) Network conditions are always changing... traffic bandwidth hosts going offline Packets “hop” from host to host. Each host only knows what general direction the packet is headed. Each host knows which of its neighboring hosts lie in which direction. If transmission to a neighbor fails, the host updates its information. Each packet is given a “time-to-live” number. Each hop subtracts from the “time-to-live.” If the packet reaches 0 it is deleted. Each packet has a header. source address destination address checksum Protocological characteristics of TCP/IP facilitates peer-to-peer communication distributed technology (meshwork/rhizome) universal language (any 2 computers that speak TCP/IP can network) robust and flexible/ not rigid and tough open to theoretically unlimited variety of computers is a result of the action of autonomous agents (computers)