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The Big Picture. Bond University, IT School Tan Alam Acknowledgment: Alexander Zangerl. PART A: INTERNET Internet History. http://www.zakon.org/robert/internet/timeline/ 1969: ARPA ARPA: Advanced Research Projects Agency (US) Commissioned by DoD during cold war
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The Big Picture Bond University, IT School Tan AlamAcknowledgment: Alexander Zangerl
PART A: INTERNET Internet History • http://www.zakon.org/robert/internet/timeline/ • 1969: ARPA • ARPA: Advanced Research Projects Agency (US) • Commissioned by DoD during cold war • Control over network to service Nuce War • public teleph net was vulnerable • packet-switching network • 4 node ARPANET (UCLA, SRI, UCSB, UoU)
Internet History • 1975 • First ARPANET mailing list, MsgGroup, is created by Steve Walker. • John Vittal develops MSG, the first all-inclusive email program providing replying, forwarding capabilities.
Internet History • 1983: Name server developed at Univ of Wisconsin, no longer requiring users to know the exact path to other systems • 1985: NSF (US national science foundation) links supercomputers & universities • late 80's • first commercial ISPs
Internet History • 1990: ANS (Advance Networks and Services) took over NSFNET, • Updated 1.5 Mbps links to 45 Mbps • Early 90's: NSF awarded contract to PacBell, Ameritech, MFS, Sprint to build NAPs -- to ease transition and make sure every regional network could communicate with every other regional network
Internet History • Mid 90's • explosive growth of the net • Mosaic 1, web browser (hit the market in 93, images) • Netscape 1 was founded in Dec 94, Mozilla • Sun: Java was invented
Internet History • Late 90's • net abuse & censorship • Microsoft: tries to reinvent/control/rule Browser War http://www.quirksmode.org/browsers/history.html Microsoft targeted web designers with little knowledge • Reflow of pages
What is the Internet? • A global network of networks • network connecting hosts • hosts can transparently communicate with other hosts • provide services • access services • based on IP packet switching
Involved Parties • User PC • at home/company • multimedia (sound, video, graphics) • User Communication Equipment • Modem (plugs into phone, 56 kbit/s) • Cable modem (plugs into Cable TV outlet) 2-10Mbit • ISDN adapter (plugs into ISDN outlet) 2x 64kbit
Parties (cont'd) • Organisation Communication Equipment • Ethernet card (plugs into LAN, 10, 100Mbit) • Token Ring card (plugs into LAN) • company firewall (hopefully well configured) • Router plugs into leased line (LL) etc.
Parties (cont'd) • ISPs (Internet Service Provider) • Dial-up infrastructured, lease line infrastructure • backbone (Ethernet, optic fibre, satellite links) • services • transport of your data to and from the internet • DNS, mail, web hosting • national peering (NAPs) • international connectivity/peering
Parties (cont'd) • Carriers • backbone providers • AT&T, Sprint, MCI/WorldCom, C&W, Qwest • optic fibre (Gbits) • switches • interconnection points (bridges, hubs, repeaters etc.)
Online providers (classes) • Carriers (Sprint, AT&T, C&W, Qwest) • only (leasable) lines • Internet Service Provider (BigPond, ...) • IP traffic & routing, essential services (DNS) • Content Service Providers (AOL, MSN) • IP traffic and content • online news, ....
Internet Administration • No central authority • organisational bodies • IANA (provides DNS, http://www.iana.org/) • ICANN (http://www.icann.org/ new assignment authority) • IETF, engineering task force (www.ietf.org) • W3O, world wide web consortium (http://www.w3.org/) • CERT (Internet security)
Internet Standards • RFCs, • request for comments • published concept, technique or protocol as draft • IETF gives comments • work groups, related issues • review process • publishing queue of editor • RFC2223
Internet Impact • accessibility of information • experts, governments, university • speed of technology change • new industries • ISPs, web agencies, consulters, application providers, portals • e-commerce (C2B, B2B) • reseller chains, interfacing/tracking customers
Internet Impact • Results • decentralized • not really easy to control • but all governments would like to... • lots of anti-privacy laws...
Netiquette • Conduct guidelines • RFC1855 • Mail: be concise, don't fire mails in anger • Be proud of what you say • Web: be careful when doing e-commerce • VideoConferencing: wear shirts ;-)
PART B • Binary to Decimal • Decimal to Binary • Hex • https://james.bond.edu.au/courses/inft12230/043/Labs/week1.html • Gates: AND, OR
Throughput and Bandwidth • Throughput - the amount of data that a communications channel can carry during a given period of time. • The physical nature of every communications channel determines its potential throughput. • Bandwidth - a measure of the difference between the highest and lowest frequencies that a media can transmit.
Terminology • Standalone workstation - a workstation that is not connected to a network, but relies on its own hard disk for operating system files, data storage and applications. • Client - a workstation or Node/Host connected to a network. A person whose workstation is part of a network may also be called a client, or that person may be known more informally as a user. • Server – special purpose Nodes/Hosts on a network that can store shared data and programs. They can also perform management functions, such as determining which users have access to certain programs.
Requirements for Communications • Node - any device (for example, a server, client, or printer) that can receive a transmission over a network. To receive data, each node must have a unique address, or identifying number. • Protocol - a policy/standard that governs how the parts of a network communicate
Servers • Server - A Node/Host on the network that manages shared resources. • Network operating system (NOS) - software that can manage not only data, but also users, groups, security, and applications on the network.
LANS, MANS, and WANS • Local area network (LAN) - a network of nodes (computers and other devices) that is confined to a relatively small space, such as one building or even one office. Usually under local administration control and owned by the organization.
LANS, MANS, and WANS • Metropolitan area network (MAN) - a network that connects nodes and network segments in multiple buildings in a region. Usually connecting sub-networks (subnets) or small networks together to form a larger network. These networks are usually owned by the one company or connected together for business reasons. Administration can be centralized or distributed – in-house or independent.
LANS, MANS, and WANS • Wide area network (WAN) - a network that connects two or more geographically distinct LANs into one larger network enabling the nodes on all networks to communicate with each other
The Internet • The Internet is a unique WAN not only because of its size, but also because of its diversity. • It may transmit confidential information between two offices within the same organization, or it may transmit public records to anyone who requests them. • To connect users from around the globe, the Internet relies on a hierarchical structure of connection points, just as the PSTN relies on a hierarchy of central offices. • An Internet Service Provider (ISP) is a company that operates a network and provides consumers with a link to the Internet.
Switching • A method of establishing connections and sending information between nodes on a network • Used in both voice and data communication • Circuit, message, packet switching,
Circuit Switching • Establishing a connection between two devices on a network, before they begin transmitting data. • All data follows the same path (set up) between the two devices • Bandwidth is reserved and dedicated to the path until the connection is terminated. • Can be inefficient use of bandwidth, good for real-time applications eg.voice, video, etc.
Message Switching • ‘Store and Forward’ • Same path • Not dedicated connection –allows sharing of channels • Requires intermediate nodes to have storage capacity • Not often used except for E-mail
Packet Switching • Most common • Large data/message is split into specific size (max) Packets • Each packet has the source and destination address and its place in the larger message • Each packet can travel a different path to the destination • All packets are reassembled back into the larger message at the final destination ONLY
Packet Switching • Advantages • Each packet can find the fastest path available (now) • Each packet can take a different path and not have to travel single file • Disadvantages • Some time is needed to reassemble packets into the larger message at the destination • Some packets may be delayed on their path – meaning the reassembly is delayed • Some packets may be lost on their path – meaning that some packets reach the destination but not all so reassembly is impossible • These time delays make it unsuitable for real-time applications