History & Technologies of the InternetLecture 1 – September 22, 2016

―Lincoln Towers University‖Sept. 22 – Oct. 13, 2016

Thursdays 7:30-9 pm, 150 WEA Community Room

Instructor: Stephen Weinstein

s.weinstein@ieee.org, (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 communications industry. I am

a member of the Boards of the 150WEA Owners Corp. and

of Project Open*. My consulting website, cttcservices.com,

has further personal background information.

*I maintain the Project Open web site, projectopenlincolntowers.org

Goals of this course

1. Provide an intuitive explanation, not requiring an

engineering or computer science background, of

-Internet history

-The technical foundations of the Internet

-Relevant basic concepts of communications and

information technology.

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 computers 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 Digital Media

-Definitions of a few basic terms (data, digital, bit, packet & packet switching, 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 probablybe left to Lecture 2.

Lecture 2: Digital Media and Communications

-Basic concepts: frequency, wavelength, bandwidth & data rate.

-History of digital/data and wireless communication.

-Why digital? - and how conventional analog media (voice,images, video) are converted to digital.

-Modulation and modems.

-The different kinds of communication networks supportingthe Internet; protocol stacks.

Lecture 3: Internet architecture & technologies

-Internet architecture (routers, domain name service, …).

-Connection-oriented vs. connectionless (datagram).

-The most important communication protocols used inthe 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 World Wide Web: History, browsers, and web pages.

-Audio and video streaming, voice over IP.

-Cloud computing.

-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 representinformation.

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 computerhard 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 theset: 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 usebinary numbers to represent an integer by multiples of powers of 2.

Example: 14 (decimal) is the same as1110 (binary) = 1x8 + 1x4 + 1x2 + 0x1

14 and 1110 are both digital representations of the same quantity!

Data Stream: A sequence of digital numbers (sometimescalled digital ―words‖) representing an information objectsuch as a movie.

Example of decimal and binary digital data streams for the sameinformation:

14 05 12 15 02 …..1110 0101 1100 1111 0010 …..

Movies streamed from Netflix or other Internet sources come inbinary 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).Byte: 8 bits. Megabyte (MB): A million bits. Gigabyte (GB): abillion 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 signal can be represented by a data sequence of bits.

Analog to digital conversion

…0111 0000 1101 0100 ...

A/D

Sound pressure wave in air (analog)

Network (for data communications): A set of originating and terminating entities, forwarding nodes, and the transport links connecting them, for conveying data traffic.

Switch (in traditional telephone network)

or router (in Internet and other packet networks).

Terminating device (phone,

computer, cell phone, etc.)

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 trucksthat may possibly be of different sizes.

Packet multiplexing: A mixed stream of packets from different sources.

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

1-video1-video 1-video1-video

2-voice 3-keyboard

Packet switching (routing) vs. traditional line switchingat a network node

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 ―header‖, sending and receiving addresses, information quantity, and information type.

Simple packet model:

Header Information field (payload)

Source & destination addresses, etc.

Bluetooth

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.

WiFi(IEEE 802.11)

DSL

Optical Core Network,

metropolitan & long haul

Local AreaNetworks

Cellularmobile

Cable (HFC)

Ethernet Opticalfiber

Accessnetworks

Personal AreaNetworks

CoreNetworks

Bluetooth

Infrared

Satellite

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

Optical Core Network,

metropolitan & long haul

Cellularmobile

Cable (HFC)

EthernetOpticalfiber

Bluetooth

IPWireless router

IP DomainNameServer

WiFi

The Internet is one example ofan internet

Router

LawrenceRoberts

LeonardKleinrock

PaulBaran

DonaldDavies

RobertKahnVinton

Cerf

J.C.R. Licklider

History of the Internet

JonPostel

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.

Refs: https://www.internetsociety.org/internet/what-internet/history-internet/brief-history-internet1 L. Kleinrock, "Information Flow in Large Communication Nets", MIT RLE Quarterly Progress Report, July 1961.

Kleinrock message switching1: "Basically, what I did for

my PhD research in 1961–1962 was to establish a mathematical theory of packet

networks...―.

Mid 60s: Publications on packet switching from RAND (Paul Baran) and the National Physical Lab in the U.K. (Donald Davies).

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 systemin which a broken route couldeasily be replaced by another.2 Hecalled it ―hot potato‖ routing oradaptive ―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.pdf2 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.

DaviesTuringNPL

PS: packet switch

UM: User machine (computer)

T: Terminal

TP: Terminal ProcessorR. Scantlebury & P. Wilkinson, ―The National Physical Laboratory Communication Network‖,

Proc. ICCC 1974, available at http://rogerdmoore.ca/PS/NPLPh/NPL1974A.html

Ref: https://www.internetsociety.org/internet/what-internet/history-internet/brief-history-internet

Incoming packets onseveral lines Outgoing packets on

several lines

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 desiredoutput line.

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:

Network topology

& 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, implementedin 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 hypertext system. Engelbart was also the inventor ofthe computer mouse.

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

Knowledge linking, collaborative work, …

Why did they want a packet-switching data network rather than a line switching network like the telephone network?

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 keyboardentry) 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 differentnetworks.

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 predecessorof TCP.

Steve Crocker

S. Crocker, J. Postel, J. Newkirk & M. Kraley, ―An Office Protocol Proffering‖, RFC 54,

June 18, 1970.

Fall 1972: Bob Kahn demonstrates ARPANET services at the International Conference on Computer Communications (Washington). I was there. Unfortunately no photos are available.

1973: Vint Cerf 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 internetworking 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, process-to-process connections.

ARPANET geographic map, July, 1976http://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 supercomputers. 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 Michigan 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 Al Gore 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 Mosaic web browser was developed there.

2012, Gore was inducted into the Internet Hall of Fame 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 United States 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 physicistsexchange information.

World Wide Web technologies (web sites and addresses, hypertext description language, …) will be explained in Lecture 4.

Early web browser

Tim Berners-Lee

28 Feb. 1990: ARPANET formally decommissioned. It was nottransformed into the Internet; they were different entities with theInternet 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 bytes per month by end 1994.

Internet Service Providers (ISPs), providing dial-up access to the Internet for consumers, began to appear, some extensions of earlieron-line content providers, including:CompuServe, BIX, AOL, DELPHI, Prodigy, UUNET, The Pipeline, Panix, Netcom, the World, EarthLink, and MindSpring

1993: My wife, Judy, and I, together with several Bellcore, NJ Belland Morris County Information Network colleagues, launch MORENET, second only to Seattle in providing Internet access 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 tofull 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 Jon Postel, 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).

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

Deborah Estrin

In early-mid 1990s, made important contributions to Internet routing.

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

IETFInternet EngineeringTask Force

IABInternet ArchitectureBoard

ICANNInternet Corporationfor Assigned Names & Numbers

IESGInternet EngineeringSteering Group

NTIANat. Telecommun. &Infor. Administration

[Functions on next several slides]

ISOCInternet Society

IANA functionsInternet AssignedNumbers Authority

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 appealEditorial management and publication of the Request for Comments (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 address space allocation, protocol parameter assignment, domain name system management, and root server system management functions. Jon Postel created this vital activity in the1970s, 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 Telecommunications 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 BillBy THE ASSOCIATED PRESS, 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)