- Internet History
- - Prelude 1950-65
- - - Paul Baran
- - ARPANET 1966-68
- - Birth of ARPANET 1969
- - ARPANET 1970s
- - - TCP/IP
- - Internet 1980s
- - - NSFNET
- - 1990s
- - - CIX
- - DNS
- - World Wide Web
- - VoIP
- - Backbone
- - Internet2
- - Reference
- - - NSFNET
- - 1990s
- - - CIX
- - DNS
- - World Wide Web
- - VoIP
- - Backbone
- - Internet2
- - Reference
- Wireless / Radio
- Common Carrier
- - Communications Act
- - Telecom Act
- - Hush a Phone
- - Computer Inquiries
- - Digital Tornado 1997
- - Steven Report 1998
- - Broadband
- - Universal Service
- - VoIP
- - Mergers
- - Network Neutrality
UCLA operates the ARPANet NOC
March: ARPANet connects from West Coast to East Coast at BBN. [Roberts, Net Chronology][Abbate p 64]
Lawrence G. Roberts & Barry D. Wessler, Computer Network Development to Achieve Resource Sharing, in Proceedings of AFIPS Spring Joint Computer Conference (AFIPS Press, 1970).
ARPA's contract with BBN to build IMPs is extended. [Nerds p 100]
Host to Host
1983 - ??
1996 - ??
Steve Crocker recounts that while they were given this IMP to operate, they kept expecting at some point someone would show up and tell them what they should be doing; they never did show up. While awaiting for direction, it was decided that they needed some system of tracking and recording their work. To that end, Crocker created the Network Working Group (NWG), the forerunner of the IETF in 1986. NWG meets in Atlanta [Padlipsky] [Salus p 29]
Crocker was concerned that the act of writing things down would be an assertion of authority. To emphasize that these were not official decrees, the documents produced by this body came to be known as Requests for Comment. Crocker figured that this would go on for a few months until Washington DC stepped in and told them what to do.
Vint Cerf: "we were just rank amateurs, and we were expecting that some authority would finally come along and say, "Here's how we are going to do it." And nobody ever came along, so we were sort of tentatively feeling our way into how we could go about getting the software up and running." [Cerf, Oral History 1990]
Steve Crocker leading, releases the Network Control Protocol (NCP), the initial host-to-host protocol. [ISOC] [Roberts, Net Chronology] [Abbate p 68] This will become the Internet Configuration Control Board.
"NCP relied on ARPANET to provide end-to-end reliability. If any packets were lost, the protocol (and presumably any applications it supported) would come to a grinding halt. In this model NCP had no end-end host error control, since the ARPANET was to be the only network in existence and it would be so reliable that no error control would be required on the part of the hosts." [ISOC]
RFC 33; Crocker, S.; Carr, S.; Cerf, V.; New HOST-HOST Protocol ; 12 Feb 1970. RFC 36; Crocker, S.; Protocol Notes ; 16 Mar 1970 . RFC 78; Harslem, E.; Heafner, J.; White, J.; NCP Status Report: UCSB/RAND; Nov 1970.
Xerox PARC established. Robert Taylor moves to Xerox PARC. [Markoff Dec. 20, 1999]
July: Norman Abramson builds ALOHANet, using DARPA and NAVY funding. [Nerds 2.0.1] ARPA provides a Terminal Interface Processor to ALOHANet [Nerds p 103] [Roberts, Net Chronology] [Abbate p 115]
Stu Mathison, Phil Walker, and Barry Wessler meet during the summer to discuss building a commercial network based on ARPANET technology (will become Telenet) [History of Telenet p 29]
Steve J. Lukasik becomes director of ARPA. He will leave ARPA in 1975 and he will join the FCC as Chief Technologist in 1979. [Lukasik]
Roberts intended a two phase start to the ARPANET:
Phase One: started in 1969 as Initial Research and Experimental Use, with the original 14 nodes and about 2000 people." These ARPA-funded researchers were engaged in Computer System Architecture, Information System Design, Information Handling, Computer Augmented Problem Solving, Intelligent Systems, and Computer Networks. "The major use they will make of the network is the sharing of software resources and the educational experience of using a wider variety of systems than previously possible." A major purpose in this phase is the experiment of the network itself, with Stanford operating the NIC, gathering and monitoring network information. Phase Two: intended to initiate after November 1970 to open the network up to the external research community use, expanding the network to about 20 notes. This would open the ARPANET to additional ARPA funded researchers in the areas of Behavioral Science, Climate Dynamics and Seismology.
[Roberts Wessler 1970]
1400 Wilson Blvd, Rosslyn, Arlington, Virginia, was the home of ARPANET from 1970 to 1975. This historic marker was installed in 2011 on the sidewalk outside the old ARRPANET building. It reads:
"The ARPANET, a project of the Advanced Research Projects Agency of the Department of Defense, developed the technology that became the foundation for the Internet at this site from 1970 to 1975. Originally intended to support military needs, ARPANET technology was soon applied to civilian uses, allowing information to be rapidly and widely available. The Internet, and services such as e-mail, e-commerce and the World Wide Web, continues to grow as the under-lying technologies evolve. The innovations inspired by the ARPANET have provided great benefits for society."
The binary sign spells out "ARPANET." Pictured are (Left to Right) Robert Young; Christopher Zimmerman, chair of the Arlington County Board; George Lawrence; Steve Lukasik, former ARPA director; Eric Willis; and Francis Niedenfuhr. Picture was taken during an Arlington County Board ceremony.
19 nodes on ARPANet including UCLA, SRI, UCSB, Uni Utah, BBN, MIT, RAND, SDC, Harvard, Lincoln Lab, Stanford, U of Ill Urbana, Case Western Reserve, CMU, NASA-Ames [Hauben]
Steve Crocker joins IPTO as a program manager.
Larry Roberts wants to avoid DoD owning and operating the Internet. Therefore Roberts approaches AT&T offering it to them, offering to give them the network and have the USG as an anchor tenant customer. "AT&T could have owned the network as a monopoly service, but in the end declined." "They finally concluded that the packet technology was incompatible with the AT&T network," Roberts said." AT&T would not build its first packet switched network until 1982.[History of Telenet p. 29]"Bob Taylor also tried to talk to AT&T about the venture. "When I asked AT&T to participate in the ARPANet, they assured me that packet switching wouldn't work. So that didn't go very far." " [Nerds2.0 p 74]
Larry Roberts said, "They wouldn't buy it when we were done. We had decided that it was best if industry ran it, because the government had done its experiment and didn't need to run it anymore. I went to AT&T and I made an official offer to them to buy the network from us and take it over. We'd give it to them basically. Let them take it over and they could continue to expand it commercially and sell the service back to the government. So they would have a huge contract to buy service back. And they had a huge meeting and they went through Bell Labs and they made a serious decision and they said it was incompatible with their network. They couldn't possibly consider it. It was not something they could use. Or sell." [Nerds p 109] [See also Vanity Fair (quoting Baran " The one hurdle packet switching faced was AT&T. They fought it tooth and nail at the beginning. They tried all sorts of things to stop it.")]
"Roberts discussed the issue with Bernie Strassburg, Chief of the Common Carrier Bureau of the FCC. Strassburg advised that the best approach would be to form a new com pany and apply for an operating license from the FCC." [History of Telenet p. 29] This would be Telenet.
See Western Union's Decision not to buy the Bell telephone patents 1876.
Stephen Lukasik becomes Chief of ARPA. He was a major proponent of network research of of electronic mail. Would become FCC Chief Scientist in 1979.
Alex McKenzie took charge of the Network Control Center at BBN. He envisioned the ARPANET as a "computing utility." [Abbate p 65]
A Bhushan, RFC 114, A File Transfer Protocol (April 16, 1971)
T O'Sullivan, NWG RFC 158, TELNET Protocol (May 19, 1971)
Project Guttenberg is initiated with the posting of a copy of the Declaration of Independence to Michael Hart's site at the Uni of Illinois.
Computer History Museum
Robert Kahn leaves BBN, joins IPTO. [Kahn][Nerds p 109][Vanity Fair] [Waldrop 83]
Vint Cerf completes dissertation at UCLA in March, goes to Stanford to teach. [Cerf, Oral History 1990]
ARPA conducts Public demonstration of ARPANet at the IEEE International Computer Communications Conference (the ARPANet's coming out party) at the Washington Hilton Hotel [Babbage 25] [Nerds p 107] [Cerf, Oral History 1990] [Abbate p 79] Demonstration to AT&T reportedly failed but the demonstration to everyone else was successful and persuasive.[Vanity Fair quoting Metcalfe ("And I turned around to look at these 10, 12 AT&T suits, and they were all laughing. And it was in that moment that AT&T became my bête noire, because I realized in that moment that these sons of bitches were rooting against me.")] [Hauber] After the success of the conference, network traffic increased 67% and continued strong growth thereafter. [Abbate p 79]
With the public demonstration of the ARPANET, the "experiment in packet switching" is established as a success. This marks the transition of the ARPANet from an experimental network to an operational network. [Abbate p 114]
Last Apollo flight to the moon [Apollo]
ARPA rechartered as DARPA, removing ARPA from the Office of the Secretary of Defense. [Hauber] [RFC 1000]
Cost of setting up an ARPANET node: $55k - $107k. [Abbate p 84]
J. Pickens, RFC 369, Evaluation of ARPANET Services; January through March 1972 (July 25, 1972)
Steward Brand, Spacewar: Fanatic Life and Symbolic Death Among the Computer Bums, Rolling Stone (Dec. 7, 1972) (includes good description of ARPANet)
October: BBN proposes setting up separate subsidiary to establish a commercial public packet switched network service. Formed the Telenet Communications Corporation. [History of Telenet p. 32]
Ray Tomlinson invents network email and adopts the "@" sign.
January: 35 nodes to network [Hauben] [History of Telenet p 29 (38 nodes by 1973)]
ARPANet connected to sites in Norway and England using Intelsat I satellite. [Hauben] [Abbate p 121]
CYCLADES network is demonstrated in France.
March: SRI initiates publication of the ARPANET News [Abbate p 87]
Oct: Larry Roberts leaves IPTO to become CEO of Telenet (first public commercial packet-switched network, a subsidiary of BBN). [Roberts, Net Chronology] [Abbate p 80] [Heart p 24 1990] [History of Telenet]
Robert Kahn becomes head of IPTO. [Kahn]
"Packet Communication by R. M. Metcalfe, MAC TR-114, Dec. 1973"
Federal Communications Commission
Lee Talbert (formerly BBN), Ralph Alter, Steve Russell for Packet Communications Inc. (PCI) and in January 1973 apply for authorization from the FCC to build a public packet switched communications network. The application was approved in November, however, PCI was not able to raise sufficient funding to build out. [History of Telenet p. 32]
|While the ARPANET was restricted to ARPANET funded or affiliated sites at universities and contractors, once a connection was established, access to the connection was relatively open. "'Few system administrators tried to add access restrictions to the network commands. According to BBN's ARPANET Completion Report, "despite a deeply ingrained government and Defense Department worry about unauthorized use of government facilities, it was possible to build the ARPANET without complex administrative control over access or complex login procedures or complex accounting of exactly who was using the net for what.' BBN argued that this relax access policy made the system simpler and thus contributed to its quick and successful completion." [Abbate p 79]|
Arthur C. Clarke Predicts the Internet & PC
Licklider returns as head of IPTO.
Steve Crocker leaves IPTO and returns to UCLA. [Salus p 29]
ARPANet in 1973 (image in NIH)
Ethernet Will Never Work - 1974 Xerox PARC memo...., Broadband Reports 6/13/2007
Larry Roberts, Data by the Packet, IEEE Spectrum Vol. 11, No. 2, pp. 46-51 (Feb. 1974)
Vinton Cerf, Yogen Dala, Carl Sunshine, RFC 675 - Specification of Internet Transmission Control Program (Dec. 1974) (2 8 host addresses / 2 4 net addresses)
"In 1974 Western Union was awarded a contract by DCA to develop a packet switching network called AUTODIN II. AUTODIN I, which has been leased to the government since the 60s, uses a message forwarding scheme." John Roberts, The Defense Data Network
DCA Takes Control of ARPANET [Hauber]
Richard Barber, The Advanced Research Projects Agency, 1958-1974 (Defense Technical Information Center Dec 1975) (PDF)
"This historical evaluation of the Advanced Research Projects Agency (ARPA) as an R&D management institution was commissioned by ARPA in recognition of the fact that remarkably little in the way of an official recorded institutional memory had been established during its seventeen year lifetime. From Agency Directors to program managers, the turnover in its leadership has been rapid by most bureaucratic standards, thus eroding first hand knowledge of ARPA's role and activities rather quickly. Conceived as a unique management organization chartered to concentrate on advanced research within the Department of Defense, this very uniqueness has frequently been questioned. Virtually every ARPA Director, and most ARPA personnel at all levels, have encountered friendly and not-so-friendly why ARPA? and what is ARPA? questions throughout its history. This report seeks to explain some of the whys and whats. For the most part, the study ends in 1972 when ARPA was designated a Defense Agency. This date was arbitrarily chosen. In instances where events or programs started in earlier periods extend beyond 1972, they have been pursued a bit further for sake of completeness, but not past 1974."
SATNET initiated. First satellite network on the Internet. SATNET was DARPA-Sponsored. [RFC 2555] Connected Stanford US, University College London England and Norway. INTELSAT. Would be a part of a TCP/IP interconnectivity demonstration with ARPANET in 1977. [Living Internet TCP/IP] [Abbate p 121]
Telenet begins offering public packet-switched network service in seven cities. [Nerds p. 115] [Abbate p 80] [History of Telenet]
DECNet released [DECNet, CISCO]
"By mid-1975, DARPA had concluded that the ARPANET was stable and should be turned over to a separate agency for operational management. Responsibility was therefore transferred to the Defense Communications Agency (now known as the Defense Information Systems Agency)." [Cerf Com Com Nets] [Roberts, Net Chronology] Note, DISA's official history does not mention its role with the ARPANet. [DISA Our History] DCA will make the decision to migration ARPANet from NCP to TCP in 1980.
Stephen Lukasik leaves his position as Chief of ARPA. Joins FCC in 1979.
PRNET become operational in San Francisco. [Abbate p 118]
Licklider leaves ARPA again, succeeded by Col David Russell.
Queen of England sends email to her subjects celebrating the 25th anniversary of her coronation [Nerds p 113] (where Pres. Bush Jr when he came to office in 2000 indicated that he would refuse to use email) .
X.25 Standard adopted. [History of Telenet 38]
Cerf joins ARPA. [Nerds p 114] [Roberts, Net Chronology] [Waldrop 85]
MERIT interconnects with Telenet. [Merit History] MFENet provides data links between Fusion Energy and Lawrence Livermore National Labs [ESNet History] Experimental Packet Switching Service, operated by the British Post Office, goes online. [History of Telenet 38]
1977 First Internet experimental demonstration
Internet Milestone - 30th Anniversary 3-Network Transmission
Computer History Museum (panel starts at min. 21)
111 Host computers connected to ARPANet. [Hauben]
OSI Subcommittee established. [Salus p 39]
Nov. 22 Cerf and Kahn demonstrate interconnection of networks using IP by interconnecting ARPANet, SatNet, Ethernet, and PRNET. Gateways supplied by BBN.. [Nerds p 113] [Cerf Com Com Nets] [Living Internet TCP/IP] [Cerf Crocker, Nov 2011, Smithsonian American Art Museum lecture] [Bob Kahn, the Bread Truck, and the Internet's First Communion, Wired Aug. 13, 2012]
Compuserv offers computer time sharing services BBN develops first Internet Routers in collaboration with Stanford. [BBN Timeline]
Datapac (Canada) goes online [History of Telenet 38]
IPv3 splits TCP and IP.
NTIA Dept of Commerce releases ARPANET Host to Host access and disengagement measurements , 78-3 May 1978
Clark and Cohen, Internet Engineering Note (IEN) 46 June 1978 A proposal for addressing and routing in the internet: "The current internet header has space to name 256 networks. The assumption, at least for the time being, is that any network entering the internet will be assigned one of these numbers. While it is not likely that a great number of large nets, such as the ARPANET, will join the internet, the trend toward local area networking suggests that a very large number of small networks can be expected in the internet in the not too distant future. We should thus begin to prepare for the day when there are more than 256 networks participating in the internet."
BBN demonstrates packet satellite communications. [BBN Timeline]
Transpac (France) goes online [History of Telenet 38]
Robert Kahn succeeded David Russell as head of IPTO, would serve in that position until 1986. [Waldrop 85]
Vint Cerf at DARPA establishes the Internet Configuration Control Board (forerunner of the IETF; previously had been the Network Working Group). David Clark at MIT was named chair. [Great Moments] [Kessler] [Salus p 205] [Cerf 1160] [Kahn, Role of Govt]
USG announces OSI as a layered computing standard.
MUDs Multi User Dungeons
FCC Chair Ferris recruits S. J. Lukasik to be FCC Chief Scientist in the Office of Science & Technology (currently the Office of Engineering and Technology); Lukasik had been Chief of ARPA from 1971 to 1975. [M Marcus 2008] [Lukasik 1982]
Compuserv's online service Compuserv Information Service begins to offer service NTT packet net goes online [History of Telenet 38]
It was clear that the Network Control Protocol would need to be revised in order to enable the ARPANet to interconnect with other, dissimilar networks. Cerf explained, "In defense settings, circumstances often prevented detailed planning for communication system deployment, and a dynamic, packet-oriented, multiple-network design provided the basis for a highly robust and flexible network to support command-and-control applications." In 1972, Vint Cerf (Stanford; DARPA funding; Cerf had worked on the original NCP) and Bob Kahn (ARPA) released their paper on TCP, A Protocol for Packet Network Interconnection (distributed in 1973, published IEEE Transactions of Communications Technology 1974) [See also Vanity Fair] [RFC 675, Specification of Internet Transmission Control Program , December 1974] [Abbate p 113]
Cerf has been a graduate student of Kleinrock at UCLA. [Waldrop 84]
TCP would be broken into TCP/IP. That facilitated real time voice applications. TCP's error control protocols which caused packets to be resent was both unnecessary for real time voice and in fact got in the way. By separating TCP and IP, this allowed different error control protocols such as UDP which, if the packet is not delivered on time, just drops and does not retransmit the packet. [Vint Cerf, How the Internet Came to Be, NetValley Nov 20, 2006] "IP would be responsible for routing packets across multiple networks and TCP for converting messages into streams of packets and reassembling them into messages with few errors despite loss of packets the underlying network." [Denning 4] [Vint Cerf, TCP/IP Co Designer, Living Internet] [ISOC] [Roberts, Net Chronology] The phrase "Internet" was first used in RFC 675.[Roberts History s 6]
Further development of TCP/IP was funded by DARPA, with three contracts to Stanford, BBN, and UCL. [ISOC] Vint Cerf and others went through several versions: TCPv1; TCPv2; TCP/IPv3 (splitting TCP into TCP and IP), and, in 1978, they settled on IPversion4. [Living Internet TCP/IP]
TCP/IP was successfully used in 1977 to link together 4 networks.
IP as originally designed had an eight bit networking field which would be sufficient for at maximum 256 networks - it was believed at the time that this would be more than enough. [Nerds2.0 p 112] [Netvalle]
R. Kahn, Communications Principles for Operating Systems. Internal BBN memorandum, Jan. 1972.
Vint Cerf & Robert Kahn, A Protocol for Packet Network Interconnection, IEEE Transactions of Communications Technology (May 1974)
Vint Cerf, Yogen Dalal, Carl Sunshine, Specifications of Internet Transmission Control Protocol NWG RFC 675 (Dec. 1974)
Visionaries at US Department of Defense DARPA realized the value to the research community if computer networks could talk to each other - sharing resources and sharing research. In 1969, the DARPA funded ARPANet went online. Meanwhile, Vint Cerf and Bob Kahn set to work on developing a new protocol that would allow incompatible networks to talk with each other. This new protocol would be DUMB - it would just transmit data - you could run any application over it - you could layer it on top of any physical network. It would be a middle kludge that would hold everything together. In 1972, they release their paper on the Internet Protocol. In 1983, ARPANet formally migrated to IP and morphed into "The Internet."
The Internet technically the name of one network, which is the interconnected network which use the Internet protocol and have one common IP addressing scheme. The Internet is a subnetwork of routers that just route packets. Computing processing power was scarce; in order to maximize throughput, computer processing at the router would be as limited as possible. Routers dont process packets. They dont care if they are email packets, WWW packets, or the latest innovation's packets. They dont care if the packets came over cable, DSL, or fiber. They do not discriminate. Routers just route.
"Four ground rules were critical to Kahn's early thinking:
"Each distinct network would have to stand on its own and no internal changes could be required to any such network to connect it to the Internet. "Communications would be on a best effort basis. If a packet didn't make it to the final destination, it would shortly be retransmitted from the source. "Black boxes would be used to connect the networks; these would later be called gateways and routers. There would be no information retained by the gateways about the individual flows of packets passing through them, thereby keeping them simple and avoiding complicated adaptation and recovery from various failure modes. "There would be no global control at the operations level." [ISOC]
Bob Kahn: "The idea of the Internet was that you would have multiple networks all under autonomous control. By putting this box in the middle, which we eventually called a gateway, it would allow for the federation of arbitrary numbers of networks without the need for any change made to any particular network. So if BBN had one network and AT&T had another, it would be possible to just plug the two together with a [gateway] box in the middle, and they wouldn't have to do anything to make that work other than to agree to let their networks be plugged in." [Nerds p 111]
"The Internet Protocol is designed to interconnect packet-switched communication subnetworks to form an internetwork. The IP transmits blocks of data, called internet datagrams, from sources to destinations throughout the internet. Sources and destinations are hosts located on either the same subnetwork or connected subnetworks. The IP is purposely limited in scope to provide the basic functions necessary to deliver a block of data. Each internet datagram is an independent entity unrelated to any other internet datagram. The IP does not create connections or logical circuits and has no mechanism to promote data reliability, flow control, dequensing, or other services commonly found in virtual circuit protocols." Military Standard Internet Protocol MIL-STD-1777 Sec. 4.1 (DOD DISA Aug 12, 1983)
"The Internet Protocol is designed for use in interconnected systems of packet-switched computer communication networks. Such a system has been called a "catenet" . The internet protocol provides for transmitting blocks of data called datagrams from sources to destinations, where sources and destinations are hosts identified by fixed length addresses. The internet protocol also provides for fragmentation and reassembly of long datagrams, if necessary, for transmission through "small packet" networks." RFC 791, Internet Protocol: DARPA Internet Program Protocol Specification, Sec. 1.1 (Sept 1981) . See also RFC 760, DOD Standard: Internet Protocol Sec. 1.1 (Jan. 1980) ("This document specifies the DoD Standard Internet Protocol.") (same)
Brian Carpenter, RFC 1958, Architectural Principles of the Internet (June 1996) " 2.1 Many members of the Internet community would argue that there is no architecture, but only a tradition, which was not written down for the first 25 years (or at least not by the IAB). However, in very general terms, the community believes that the goal is connectivity, the tool is the Internet Protocol, and the intelligence is end to end rather than hidden in the network. The current exponential growth of the network seems to show that connectivity is its own reward, and is more valuable than any individual application such as mail or the World-Wide Web. This connectivity requires technical cooperation between service providers, and flourishes in the increasingly liberal and competitive commercial telecommunications environment. The key to global connectivity is the inter-networking layer. The key to exploiting this layer over diverse hardware providing global connectivity is the "end to end argument"."
"3.1 Heterogeneity is inevitable and must be supported by design. Multiple types of hardware must be allowed for, e.g. transmission speeds differing by at least 7 orders of magnitude, various computer word lengths, and hosts ranging from memory-starved microprocessors up to massively parallel supercomputers. Multiple types of application protocol must be allowed for, ranging from the simplest such as remote login up to the most complex such as distributed databases.
See also End to End design.
TCP is the error correction mechanism
Assumption is that Internet is a shared resource. But when demand exceeds supply, need resolution. Technology community rely on technological solutions, not economic solutions. In the Internet, this is TCP. TPC has slow start up, ramping up packet transmission until packet lost, then backs up, then ramps up again till packet loss, and so on Resulting in TCP Fair Individual subscriber can have multiple TCP flows. Amount of TCP flow is not based on how much you used in the past few moments RFC 5290 Comments on the Usefulness of Simple Best Effort Traffic Not efficient or optimal. But a solution that has worked well for many years
"These and other documents embody some value judgments and reflect the fundamental political and ethical beliefs of the scientists and engineers who designed the Internet: the Internet architecture reflects their desire for as much openness, sharing of computing and communications resources, and broad access and use as possible. For example, the value placed on connectivity as its own reward favors gateways and interconnections over restrictions on connectivity - but the technology can be used permissively or conservatively, and recent trends show both. Another value underlying the design is a preference for simplicity over complexity." - The Internet's Coming of Age, Computer Science and Telecommunications Board, National Research Council, p. 35 (National Academy Press 2001)