The Internet is a packet data network that spans the globe and comprises multiple, authonomous, interconnected backbones all using the TCP/IP protocols. The Internet has essentially three basic elements: computers (also known as hosts, end-systems, clients, and/or servers), the networks to which they are attached, and the routers that interconnect those networks. The Internet has become an integral part of our professional and personal lives. A recent survey of a few people in our office revealed their most popular uses of the Internet include:
- Paying bills
- Sharing photographs with family and friends
- File sharing
- Investment management
In 1969 the DoD commissioned the Advanced Research Projects Agency Network (ARPANET) to research networking concepts. The nodes, Interface Memory Processors (IMPs), were built by BBN Communications—Honeywell DDP-516 minicomputers with 12K of memory. AT&T provided 50 kbps lines for interconnection. The locations and functions of the nodes were as follows.
- Node 1: UCLA, Network Measurement Center
- Node 2: Stanford Research Institute, Network Information Center (NIC)
- Node 3: University of California Santa Barbara (UCSB), Culler-Fried Interactive Mathematics
- Node 4: University of Utah, Graphics
In 1982 the Defense Communications Agency (DCA), now the Defense Information Systems Agency (DISA), and ARPA established the Transmission Control Protocol (TCP) and Internet Protocol (IP) as the protocol suite, commonly known as TCP/IP. This led to one of the first definitions of an “internet” as a connected set of networks using TCP/IP, and “Internet” as connected TCP/IP internets. In that year, the DoD declared the TCP/IP suite the standard for the DoD.
In 1990 the World Wide Web (WWW) browser and concepts were released by CERN. The first Web server was nxoc01.cern.ch, launched in November 1990 and later renamed info.cern.ch. Other noteworthy events of the year include: the NSFNET backbone upgraded to T3 (44.736 Mbps) and the NSFNET traffic passed 1 trillion bytes/month and 10 billion packets/month.
In 1994 the ARPANET/Internet celebrated its 25th anniversary, shopping malls arrived on the Internet, the first cyberstation, RT-FM, broadcast from Interop in Las Vegas, and the NSFNET traffic passed 10 trillion bytes/month. The WWW edged out Telnet to become the second most popular service on the Net (behind ftp-data) based on traffic distribution on NSFNET.
Today, the Internet2 interconnects 200 universities and 60 countries in a network that has backbone speeds that reach 10 Gbps. The number of WWW servers on the Internet is estimated at right under 50 million and the number of users on the Internet is estimated at 1 billion.
Internet Administration and Oversight
Over the years, many organizations have been involved in the administration and oversight of the constellation of networks that has come to be known as the Internet. Organizations that once played pivotal roles in overseeing the Internet include the U.S. Department of Defense (DoD), the National Science Foundation (NSF) and InterNIC, among others.
The diagram on the visual illustrates the major organizations responsible for the administration and oversight of the Internet at the current time. The group responsible for oversight of the Internet on a worldwide basis is the Internet Society (ISOC). ISOC is a board comprised of 15 individuals from around the world, many of whom have been instrumental in the development of the Internet as we know it. ISOC is headquartered in Reston, Virginia; their web site is www.isoc.org. ISOC oversees the activities of the Internet Engineering Steering Group (IESG), the Internet Corporation for Assigned Names and Numbers (ICANN) and the Internet Research Task Force (IRTF). The IESG oversees the Internet Engineering Task Force (IETF), which is the organization responsible for maintenance of the Internet standards, or RFC. The major function of ICANN is to coordinate the assignment of Internet domain names and IP addresses. ICANN handles Internet domain name assignment via designated registries. The Internet Assigned Number Authority (IANA) oversees the actual distribution of IP addresses and other important registered numbers for the Internet.
The Internet Architecture Board (IAB) has existed for quite some time, although it has been known by other monikers in the past (e.g., the Internet Configuration Control Board, or ICCB). As shown on the visual, the IAB plays an advisory role to many of the other Internet oversight groups. In addition, the IAB is the avenue by which other standards organizations (e.g., ISO, ANSI, ETSI) can impact the development and administration of the Internet.
Finally, many other organizations seek to influence the deliberations and decisions of the aforementioned oversight organizations. From foreign governments to academic institutions to vendors and ISPs, just about any group with a vested interest in the ongoing development of the internet tries to influence the ISOC hierarchy to achieve their particular ends.
Internet Request for Comments
Documents pertaining to the Internet are called Request For Comments (RFC). RFCs are numbered sequentially as they are published. Draft RFCs are called, appropriately, Internet drafts. As an RFC undergoes revision, the newer version is given a new RFC number and supersedes previous versions. For example, RFC 793 describes TCP; this RFC superseded the earlier versions of TCP, numbered 761 and 675.
The scope of RFCs is very broad and incorporates Internet protocols and lore, as well as user’s guides and tutorials. Humor has not been absent from the Internet—a lot of good technical humor can be found in any RFC dated “1 April.”
A subset of RFCs describes Internet standards. It is important to note that while all Internet standards are published as RFCs, not all RFCs are Internet standards. Internet standards (STD) are assigned a number that always refers to the latest RFCs. STD 19, for example, is the Network Basic Input/Output System (NetBIOS) Service Protocols standard, and comprises RFCs 1001 and 1002. STD 1 lists the current status of all Internet standards; it is also an RFC but the way to ensure that you are getting the latest version is to obtain “STD 1.”
Another subset of RFCs is the Best Current Practices (BCP) series. These documents have the technical approval of the IETF, but are not official Internet standards.
Yet another set includes general information for the Internet community. These For Your Information (FYI) documents also always refer to the latest RFC. FYI 1 lists all FYI documents.
Finally, the RFC series contains Technical Reports from the European research community, the Réseaux Accociés pour la Recherche Européene (RARE). In 1994, RARE merged with EARN to form the Trans-European Research and Education Networking Association (TERENA).
RFCs can be obtained electronically over the Internet using electronic mail or anonymous FTP, or on the Web at www.ietf.org/rfc/ or at www.rfc-editor.org.
For more informations see the IETF Home Page at http://www.ietf.org or RFC 2026 / BCP 0009 (The Internet Standards Process - Revision 3).
Internet Host Names
A 32 bit binary, usually shown in dotted decimal notation, IP address is used to identify host systems on the Internet. Although this is convenient for the network and for the routers, it is easier for users to remember names. It is also better for the network if users use names instead of numeric addresses; users will more accurately remember names, reducing frustration, and system administrators can move systems around without having to notify everyone about a new address.
All Internet host names follow the same general hierarchy that can be read from right to left. The rightmost part of the address represents the top-level domain (TLD). Generic top-level domain (gTLD) names used today include .com (commercial organizations), .edu (educational sites, generally colleges and universities), .gov (U.S. government agencies), .mil (U.S. military), .org (nonprofit organizations), .net (network operations hosts), and .int (international treaty organizations). The .com, .org, and .net domains were originally restricted to U.S. organizations, but are now available globally. Other top-level domains include two character country codes as defined in International Organization for Standardization (ISO) Standard 3166. ISO 3166 country codes include .au (Australia), .ch (Switzerland), .de (Germany), .fr (France), .il (Israel), .jp (Japan), .mx (Mexico), .uk (United Kingdom), and .us (U.S.A.).
The next-to-last portion of the address is generally called the second-level domain name, or simply domain name, and is assigned by the naming authority associated with each top-level domain. The fully qualified domain name hill.com, for example, is associated with the Class C IP address. When country codes are used, names are assigned by the appropriate country’s Internet naming authority. The other portions of the address are assigned by the local Internet administrator, who is probably responsible for the assignment of individual host identifiers as well. Listed below are several addressing examples from different domains.
- ftp.netscape.com: The address of the FTP server at Netscape Communications Corporation
- www.google.com: The World Wide Web (WWW) server address of a popular search engine
- iitf.doc.gov: The name of the U.S. Department of Commerce’s Information Infrastructure Task Force *WWW system; www.whitehouse.gov is the White House’s Web server
- dps.state.vt.us: The domain name for the Vermont Department of Public Safety
In November 2000, the ICANN board selected seven additional top level domains: .aero; .coop; .info; .museum; .name; .pro. For the most recent status, visit the ICANN home page at www.icann.org.
The Naming Hierarchy
The accompanying diagram shows a slightly different way of looking at the Internet host name hierarchy. As shown, the name hierarchy has a tree structure, much like the file directory structure in operating systems such as UNIX, VMS, and Windows. Like the root directory in those operating systems, the host name hierarchy has a root, denoted by a “dot” (.).
Each top-level domain (TLD) within the hierarchy has its own administration. The generic top-level domains (gTLD) .com, .org, and .net are administered by a number of different registrars verified by the Internet Corporation for Assigned Names and Numbers (ICANN) and are for global use. The .edu domain is still for U.S. educational institutions and is administered by Network Solutions, Inc. The .gov domain is for the U.S. Government (www.nic.gov) and the .mil domain is for the U.S. Military (www.nic.mil). The .int domain is used only for registering organizations established by international treaties. The .us domain and other country-code top-level domains (ccTLD) are administered by registrars approved by each country. See www.icann.org or www.iana.org for a list of registrars for each ccTLD.
Each domain registered under a TLD is in turn responsible for its own administration. For example, the network administrator for Hill Associates is responsible for administering names and addresses within the hill.com domain and for creating any subdomains that might exist under hill.com.
Added Internet Domains
The scheme of domain name assignment and management worked well for many years, but the pressure of increased commercial activity, network size, and international use caused controversy about how names can be fairly assigned without violating trademarks and conflicting claims to names. In November 1996, an Internet International Ad Hoc Committee (IAHC) was formed to resolve some of these naming issues, and to act as a focal point for the international debate over a proposal to establish additional global naming registries and top-level domains (TLD). In November 2000, the Internet Corporation for Assigned Names and Numbers (ICANN) board chose seven additional TLDs.
- .aero: For the air transport industry
- .biz: For businesses
- .coop: For cooperatives
- .info: For unrestricted use
- .museum: For museums
- .name: For registration by individuals
- .pro: For accountants, lawyers, and physicians
There is a loose hierarchy into which the components of the Internet fit. While general definitions of the various components are helpful, there are many variations in providers’ networks and interconnection profiles. Those differences are exploited by providers’ marketing and sales offices in an attempt to gain a competitive advantage, resulting in a rather confusing picture of what constitutes typical Internet connectivity.
Nevertheless, some similarities remain. At the top of the Internet connection picture are the network access points (NAP), whose responsibility it is to provide the physical and logical means for networks to interconnect. While the National Science Foundation (NSF) originally funded four NAPs, the explosion in the growth of Internet connectivity has resulted in the establishment of providers’ own NAPs, which are of greater or lesser significance depending on what technologies are implemented and the number of providers at the NAP. The original NAPs still rank at the top of the list when it comes to size, speed, number of interconnected networks, and prominence in the public mind. Large ISPs often have multiple private connections between them, referred to as peering points. NAPs are public peering points.
One step below the NAPs—and the primary reason for their existence—are the largest of the ISPs, called Tier 1 providers, national ISPs, or carrier providers. While there are no hard and fast criteria for belonging to this group, Tier 1 provider status is determined by the amount of traffic the provider generates and receives from other ISPs. Membership in the Tier 1 grouping is highly desired among ISPs.
Tier 2 providers, or regional ISPs, are smaller versions of the above networks, yet they lack the geographic reach and customer base of the bigger networks. Tier 2 providers often pay one or more of the Tier 1 providers for access to the Internet at the speeds that they (and their customers) require.
Tier 3 or local ISPs depend on other ISPs for their access to the Internet backbone. While these providers have traditionally been the corporate and consumer market entry points to the Internet, many have merged or been acquired by larger providers who value their local access facilities and customer bases.
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