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Home , Communication protocol, History of the Internet, Internet Hall of Fame, Paul Mockapetris, Steve Crocker

History & Technologies of the Lecture 1 – September 22, 2016 ―Lincoln Towers University‖ Sept. 22 – Oct. 13, 2016 Thursdays 7:30-9 pm, 150 WEA Community Room

Instructor: Stephen Weinstein

[email protected], (646) 267-5904 Lecture notes posting site: projectopenlincolntowers.org/lincolntowersuniversity Your instructor

A mostly retired engineer living in Lincoln Towers, with a PhD in electrical engineering from U.C. Berkeley and extensive experience in the industry. I am a member of the Boards of the 150WEA Owners Corp. and of Project Open*. My consulting , cttcservices.com, has further personal background .

*I maintain the Project Open web site, projectopenlincolntowers.org Goals of this course

1. Provide an intuitive explanation, not requiring an engineering or background, of -Internet history -The technical foundations of the Internet -Relevant basic concepts of communications and .

2. Answer your questions. Don’t be afraid to ask! Please have confidence in yourself to understand basic technical concepts! Important note:

This is not a course on how to use and Internet services. It is a course on how the Internet came to be, what it is, and from a science and engineering perspective, how it works. Topics Covered in Four Lectures

Lecture 1: Internet background and -Definitions of a few basic terms (data, digital, , packet & , network, protocol). -Internet definition and organizations. -Internet history (and more in future classes).

If there is time, we may introduce digital media, but this will probably be left to Lecture 2. Lecture 2: Digital Media and Communications -Basic concepts: frequency, wavelength, & data rate. -History of digital/data and . -Why digital? - and how conventional analog media (voice, images, ) are converted to digital. - and . -The different kinds of communication networks supporting the Internet; protocol stacks. Lecture 3: Internet architecture & technologies -Internet architecture (routers, domain name service, …). -Connection-oriented vs. connectionless (). -The most important communication protocols used in the Internet: IP, TCP, UDP, and some others. -Translating a web address (like projectopenlincolntowers.org) to an IP address. -Avoiding address depletion. Lecture 4: Internet applications -The original application level protocols: ftp, smtp, telnet -The : History, browsers, and web pages. -Audio and video streaming, voice over IP. -Cloud . -Security attacks (e.g., denial of service). -The Internet of Things. Lecture 1: Internet background and digital media

Basic terms. Internet definition, organizations, and history. Digital media. BASIC TERMS Data: A set or stream of symbols or numbers that represent information.

This information can be voice, video, a picture, your tax return - virtually any kind of meaningful content. These days we keep data in digital storage devices such as computer hard drives and USB memory sticks. The data is in digital format (described on the next slide). Digital: Expressed as a group of numbers chosen from a small set.

We have ten fingers and that is why we use decimal numbers from the set: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 We represent an integer by multiples of powers of 10. Example: 14 (decimal) = 1x10 + 4x1

If we had two fingers, like electronic memories, we would use binary numbers to represent an integer by multiples of powers of 2. Example: 14 (decimal) is the same as 1110 (binary) = 1x8 + 1x4 + 1x2 + 0x1 14 and 1110 are both digital representations of the same quantity! Data Stream: A sequence of digital numbers (sometimes called digital ―words‖) representing an information object such as a movie.

Example of decimal and binary streams for the same information: 14 05 12 15 02 ….. 1110 0101 1100 1111 0010 ….. Movies streamed from Netflix or other Internet sources come in binary data streams like that above. Bit: A quantity of information, equivalent to the information generated by the toss of an unbiased coin (head or tail). : 8 . (MB): A million bits. (GB): a billion bits. A bit of information is commonly represented by ―1‖ or ―0‖ rather than ―head‖ or ―tail‖, which fits nicely into a digital data stream! We will, in the next class, explain how a speech or video can be represented by a data sequence of bits.

Sound pressure wave in air (analog)

Analog to digital conversion A/D

…0111 0000 1101 0100 ... Network (for data communications): A set of originating and terminating entities, forwarding nodes, and the transport links connecting them, for conveying data traffic. Terminating device (phone, Switch (in traditional network) computer, cell phone, etc.) or (in Internet and other packet networks). Packet: A data package conveying, through a network, bits representing part or all of a message.

Complete message (digital data)

A series of packets, each carrying part of the message

It’s a lot like packing a large shipment into a series of trucks that may possibly be of different sizes. Packet : A mixed stream of packets from different sources.

The sources are represented here by the numbers 1,2,3,4.

2-voice 3-keyboard

1-video 1-video 1-video 1-video Packet switching () vs. traditional line switching at a network

Line switching: For a particular information flow for which the entire path through the network is reserved in advance, a connection is made between the input line carrying this flow and an output line on the prearranged route. Packet switching (routing) vs. traditional line switching:

Packet switching, ―datagram‖ model: Without reserving a route in advance, a particular packet is transferred to a buffer for an output line that the router selects as the best next ―hop‖. If the buffer is too full, the packet will be discarded.

The Internet implements this ―unreliable‖ routing mechanism, but with enough capacity, packet discards (or long delays) will be minimal. (Communication) protocol: A formal description of the format and rules for a message exchange. Several layers of protocols are usually needed to completely specify an information exchange.

A packet protocol, for example, will specify, in the packet ―‖, sending and receiving addresses, information quantity, and information type. Simple packet model:

Header Information field (payload)

Source & destination addresses, etc. Definitions of an internet and the Internet

An internet (not the Internet) is a combination of several distinct communication networks capable of conveying data between endpoints on different networks.

Access Core networks Networks Local Area Networks Satellite Personal Area Networks Cellular Infrared mobile

WiFi Optical Core Network, (IEEE 802.11) Cable (HFC) Bluetooth metropolitan & long haul DSL

Ethernet The Internet is the publicly available combination of multiple distinct communication networks augmented by the (IP) and subscribing to Internet standards in order to convey data through this multi-network environment.

IP Domain Name The Internet is one example of Server an internet Router Cellular mobile WiFi Cable (HFC) Optical Core Network, Bluetooth Wireless router metropolitan & long haul IP Optical fiber

Donald Davies

Lawrence Roberts J.C.R. Licklider

Robert Jon Vinton Kahn Postel Cerf 1961-62: MIT Prof. J.C.R. Licklider envisioned a "Galactic Network" as a globally interconnected set of computers through which everyone could quickly access data and programs from any site. Leonard Kleinrock published first paper on relevant packet switching theory.

Kleinrock message switching1: "Basically, what I did for my PhD research in 1961–1962 was to establish a mathematical theory of packet networks...―.

Refs: ://www.internetsociety.org/internet/what-internet/history-internet/brief-history- internet 1 L. Kleinrock, "Information Flow in Large Communication Nets", MIT RLE Quarterly Progress Report, July 1961. Mid 60s: Publications on packet switching from RAND (Paul Baran) and the National Physical Lab in the U.K. (). RAND was studying network survivability after nuclear war:

―If war does not mean the end of the earth in a black and white manner, then it follows that we should do those things that make the shade of grey as slight as possible: to plan now to minimize potential destruction and to do all those things necessary to permit the survivors of the holocaust to shuck their ashes and reconstruct the economy swiftly.‖1 His concept was a distributed system in which a broken route could easily be replaced by another.2 He called it ―hot potato‖ routing or adaptive ―message block switching.‖

1 Paul Baran, ―Reliable Digital Communications Systems Using Unreliable Network Repeater Nodes‖, the RAND Corp. report P-1995, 5/27/60, www.rand.org/content/dam/rand/pubs/papers/2008/P1995.pdf 2 http://www.rand.org/about/history/baran.list.html Donald Davies invented the terms ―packet‖ and ―packet switching‖ and built early experimental packet networks.

He initially worked at the National Physical Laboratory under Alan Turing, the great pioneer of computing whose WWII work broke the Enigma code and greatly contributed to the allied victory. Turing Davies NPL

PS: packet switch UM: User machine (computer) T: Terminal TP: Terminal Processor R. Scantlebury & P. Wilkinson, ―The National Physical Laboratory Communication Network‖, Proc. ICCC 1974, available at http://rogerdmoore.ca/PS/NPLPh/NPL1974A.html FUNCTIONS OF A PACKET SWITCH (or ROUTER) -Routing (which output line is part of the best path to destination?) -Forwarding (place packet in the waiting line (queue) for the desired output line.

Incoming packets on several lines Outgoing packets on several lines

Ref: https://www.internetsociety.org/internet/what-internet/history-internet/brief- history-internet 1968: Lawrence Roberts and colleagues at the U.S. Defense Advanced Research Projects Agency (DARPA) developed specifications and a Request for Proposals for the ARPANET, in particular for development of packet switches called Interface Message Processors (IMPs). The RFQ was won by Bolt Beranek and Newman (BBN). The first IMP was installed at UCLA in 1969.

Bob Kahn: ARPAnet architecture

Len Kleinrock: Network measurements

Larry Roberts: & economics Early ARPANET Architecture

HOST - A computer serving as an originating/terminating node. IMP- Interface Message Processor, a packet switch handling up to four Hosts and four 50Kbps communications lines, implemented in a Honeywell DDP-516 minicomputer. TIP- Terminal Interface Processor, an IMP supporting 64 terminals. T - Terminal (―dumb‖ personal computer, just keyboard and screen). Ref: http://nrg.cs.ucl.ac.uk/internet-history.html IMP The second node was at Stanford Research Institute (SRI) where Doug Engelbart’s project on ―Augmentation of Human Intellect‖ included NLS, an early system. Engelbart was also the inventor of the computer mouse.

Knowledge linking, collaborative work, … Refs: http://www.internetsociety.org/internet/what-internet/history-internet/brief-history-internet#LK61 http://www.dougengelbart.org/firsts/mouse.html D. Engelbart, ―Augmenting Human Intellect: A Conceptual framework‖, SRI Rpt. AFOSR-3223, Oct. 1962, http://www.dougengelbart.org/pubs/augment-3906.html Why did they want a packet-switching data network rather than a line switching network like the ?

Resource sharing: Access to distant computers.

Resilience: Ability to reroute packets if a link or node goes down. This was a major motivation for military networks.

Burst traffic: Ability to convey brief data bursts (like a keyboard entry) without the delay and complexity of setting up new switched lines.

Flexibility: Ability to mix different kinds of traffic (computer bursts, voice, video) at different data rates, across different networks. 1971-72: Host-to-Host (computer to computer) Network Control Protocol (NCP). NCP provided connections and flow control between processes (computer programs) running on different ARPANET host computers but did not guarantee end-to-end reliability. NCP ran on top of packet forwarding supplied by the IMP. It was the predecessor of TCP.

Steve Crocker

S. Crocker, J. Postel, J. Newkirk & M. Kraley, ―An Office Protocol Proffering‖, RFC 54, June 18, 1970. Fall 1972: demonstrates ARPANET services at the International Conference on Computer Communications (Washington). I was there. Unfortunately no photos are available. 1973: and Bob Kahn develop TCP/IP (Transport Control Protocol / Internet Protocol), a protocol pair supporting routing and reliable end-to-end connections built on IP’s ―best effort‖ (datagram) service. Enhanced across dissimilar networks (Kahn wanted to add a satellite network). Originally tightly integrated, TCP and IP were later separated to allow alternative transport-level protocols. These protocols will be described in a later lecture. Cerf and Kahn receiving Presidential Medal of Freedom, 2006 This paper largely focused on the TCP part, -to-process connections. ARPANET geographic map, July, 1976 http://mercury.lcs.mit.edu/~jnc/tech/jpg/ARPANet/G76Jul.jpg 1980: TCP/IP adopted as a defense standard. 1981: Original DARPA protocol standard for IP (RFC 791). Jan. 1983: ARPANET cutover from NCP to TCP/IP. 1983: MILNET (Military Network) split off from ARPANET. 1986: NSFnet launched by the National Science Foundation, initially to interconnect . Connection to ARPANET makes packet network more generally available to all academic users. Ref: https://www.nsf.gov/about/history/nsf0050/internet/launch.htm

http://207.75.117.26/research/nsfnet.php 1987: NSF upgrade solicitation, foreseeing commercial users. IBM, MCI and a consortium of universities win contract.

July, 1988: New backbone becomes operational, using 1.5 Mbps (megabit per second) links. This may be considered the beginning of the Internet. Demand surges, leading to replacement by 45 Mbps links in 1991. Did have a role in realization of the Internet?

Yes, indirectly, of part of the modern Internet. He was prime sponsor of the 1991 High-Performance Computing and Communications Act which allocated $600 million to the National Center for Supercomputing Applications among other entities. The early was developed there. 2012, Gore was inducted into the for being ―a key proponent of sponsoring legislation that funded the expansion of and greater public access to the Internet.‖ But he probably shouldn’t have said, in a 1999 interview with Wolf Blitzer, that ―During my service in the Congress, I took the initiative in creating the Internet.‖ https://www.washingtonpost.com/blogs/fact-checker/wp/2013/11/04/a-cautionary- tale-for-politicians-al-gore-and-the-invention-of-the-internet 1989: Tim Berners-Lee invented the World Wide Web while at CERN (European Nuclear Research Center), mainly to help physicists exchange information. World Wide Web technologies (web sites and addresses, hypertext description language, …) will be explained in Lecture 4.

Tim Berners-Lee

Early web browser 28 Feb. 1990: ARPANET formally decommissioned. It was not transformed into the Internet; they were different entities with the Internet inheriting technical concepts from ARPANET. 1991: NSF lifts ban on commercial use of NSFnet, effectively launching the Internet. Deployment of 45 Mbps links and establishment of for-profit subsidiary to enable commercial development of the network. NSF Backbone carrying 17.8 trillion per month by end 1994. Internet Service Providers (ISPs), providing dial-up access to the Internet for consumers, began to appear, some extensions of earlier on-line content providers, including: CompuServe, BIX, AOL, DELPHI, , UUNET, The Pipeline, Panix, Netcom, the World, EarthLink, and MindSpring 1993: My wife, Judy, and I, together with several Bellcore, NJ Bell and Morris County Information Network colleagues, launch MORENET, second only to Seattle in providing to public libraries including dialup from home. http://mclib.info/wp-content/uploads/2015/06/timeline.pdf April, 1995. NSFNET backbone defunded, opening the Internet to full commercial use. NSF funding was $200 million from 1986 to 1995. Regional networks now bought national-scale Internet connectivity from various long-haul network providers. Some additional Internet pioneers:

Robert Taylor Directed ARPA’s computer research program in 1960s, initiated ARPAnet project 1966, coauthored influential paper ―The Computer as a Communication Device‖ with J.C.R. Licklider

Paul Mockapetris, along with , designed and developed DNS, the domain name architecture translating a URL into an IP address.

David Clark Chairman of the Internet Activities Board in the 1980s, he was the Chief protocol architect and developer of operating rules.

Elizabeth Feinler Managed network information center (NIC) of the ARPANET, under contract to DoD. Her group developed early address servers and Host Naming Registry. She and her group developed the top-level domain-name scheme (.com, .edu, .gov, .mil, .org, and .net). Deborah Estrin In early-mid 1990s, made important contributions to Internet routing.

Steve Wolff As Division Director for Networking at the National Science Foundation (NSF) in the 1980s, he was responsible for the development of the NSFNET

Lixia Zhang Cofounder of the Internet Engineering Task Force, designed the Resource Reservation Protocol in the 1990s.

Stephen Deering Designed the multicast extension to the Internet Protocol (IP) and was principle architect of the latest version of IP, IPv6, with its immensely larger address pool. Ref: http://www.zakon.org/robert/internet/timeline/ Internet Organizations

NTIA ISOC Nat. Telecommun. & Infor. Administration

IETF Internet Engineering ICANN Task Force Internet Corporation for Assigned Names & Numbers IANA functions IESG IAB Internet Assigned Internet Engineering Internet Architecture Numbers Authority Steering Group Board [Functions on next several slides] ISOC (Internet Society) The parent organization, formal or informal, of the Internet management bodies IETF (Internet Engineering Task Force) ―The Internet Engineering Task Force (IETF) is a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and the smooth operation of the Internet. It is open to any interested individual. ― http://www.ietf.org/old/2009/overview.html Draws up RFCs (Requests for Comments), mostly proposals for enhancing Internet technologies and capabilities, that may or may not be adopted as Internet standards. Administered for many years by the famous packet networking pioneer, Jon Postel. RFC example: The original Internet Protocol RFC: 791 INTERNET PROTOCOL

DARPA INTERNET PROGRAM PROTOCOL SPECIFICATION September 1981

prepared for Defense Advanced Research Projects Agency Information Processing Techniques Office 1400 Wilson Boulevard Arlington, Virginia 22209 by Information Sciences Institute University of Southern California 4676 Admiralty Way Marina del Rey, California 90291

https://tools.ietf.org/rfc/rfc791.txt IAB (Internet Architecture Board) Architectural Oversight of protocols and procedures used by the Internet. Standards Process oversight and appeal Editorial management and publication of the (RFC) document series, and for administration of IANA assignments. IESG (Internet Engineering Steering Group) The major review body for standards. Responsible for technical management of IETF activities and the Internet standards process, specifically for the actions associated with entry into and movement along the Internet "standards track," including final approval of specifications as Internet Standards. Ref. for standards process: https://www.ietf.org/rfc/rfc2026.txt ICANN (Internet Corporation for Assigned Names and Numbers) Administers the IANA (Internet Assigned numbers Authority) functions of IP allocation, protocol parameter assignment, management, and root server system management functions. Jon Postel created this vital activity in the 1970s, as well as administering the RFCs. Example of an IP address: projectopenlincolntowers.org -----> 216.119.141.194

Currently, stewardship is being passed from the U.S. Government's National and Information Administration (NTIA) ―to the global, multi-stakeholder community.‖ Ref: http://www.internetsociety.org/ianaxfer Washington Post U.S. to relinquish remaining control over the Internet By Craig Timberg March 14, 2014

U.S. officials announced plans Friday to relinquish federal government control over the administration of the Internet, a move that pleased international critics but alarmed some business leaders and others who rely on the smooth functioning of the Web.

Pressure to let go of the final vestiges of U.S. authority over the system of Web addresses and domain names that organize the Internet has been building for more than a decade and was supercharged by the backlash last year to revelations about National Security Agency surveillance.

The change would end the long-running contract between the Commerce Department and the Internet Corporation for Assigned Names and Numbers (ICANN), a Califor- nia-based nonprofit group. That contract is set to expire next year but could be extended if the transition plan is not complete. https://www.washingtonpost.com/business/technology/us-to-relinquish-remaining-control- over-the-internet/2014/03/14/0c7472d0-abb5-11e3-adbc-888c8010c799_story.html Trump Weighs In on Internet Fight in Stopgap Spending Bill By THE , SEPT. 21, 2016, 6:25 P.M. E.D.T.

WASHINGTON — Donald Trump's campaign has inserted itself into already tricky negotiations on a temporary spending bill needed to avert a govern- ment shutdown, siding with Texas Sen. Ted Cruz in trying to block the government from ceding its limited role in overseeing some aspects of the internet.

"Donald J. Trump is committed to preserving Internet freedom for the American people and citizens all over the world. The U.S. should not turn control of the Internet over to the United Nations and the international community," senior Trump adviser Stephen Miller said in a statement.

Democratic and Republican administrations have both supported a transition of the U.S. Commerce Department's role in governing the internet's domain name addressing systems, transferring responsibility to such stakeholders as technical experts, businesses and other governments http://www.nytimes.com/aponline/2016/09/21/us/politics/ap-us-congress-rdp.html The next three lectures: The Internet’s Three Technical Foundations

-Digital Media, Communications (September 29) -Internet-Specific Technologies: Architecture, Protocols and Applications (Oct. 6 & 13)