The Internet

1. The Internet Introductory material. An overview lecture that covers Internet related topics, including a definition of the Internet, an overview of its history and growth, and standardization and naming.

2. A Definition • On October 24, 1995, the FNC unanimously passed a resolution defining the term Internet. • RESOLUTION: The Federal Networking Council (FNC) agrees that the following language reflects our definition of the term "Internet"."Internet" refers to the global information system that -- (i) is logically linked together by a globally unique address space based on the Internet Protocol (IP) or its subsequent extensions/follow-ons; (ii) is able to support communications using the Transmission Control Protocol/Internet Protocol (TCP/IP) suite or its subsequent extensions/follow-ons, and/or other IP-compatible protocols; and (iii) provides, uses or makes accessible, either publicly or privately, high level services layered on the communications and related infrastructure described herein.

3. History of the Internet Mid 1960: Papers on “Packet Switching” emerge. End 1969s: ARPA sponsors the development of a packet-switching network, called the ARPANET. 1974: The TCP/IP protocols and model are being proposed by Cerf/Kahn. 1980: IPv4 is introduced 1983: ARPANET adopts TCP/IP. At this time, the ARPANET has 200 routers. 1984: NSF funds a TCP/IP based backbone network. This backbone grows into the NSFNET, which becomes the successor of the ARPANET. 1995: NSF stops funding of NSFNET. The Internet is completely commercial.

4. Applications of the Internet • Traditional core applications:Email News Remote Login File Transfer • The killer application:World-Wide Web (WWW) • New applications:Videoconferencing Telephony P2P applications Internet Broadcast

5. Growth of the Internet Source: Internet Software Consortium

6. Internet Infrastructure

7. Internet Infrastructure • The infrastructure of the Internet consists of a federation of connected networks that are each independently managed (“autonomous system”) • Note: Each “autonomous system may consist of multiple IP networks • Autonomous systems have a number (AS number) • Hierarchy of network service providers (NSPs) • Tier-1: nation or worldwide network • Tier-2: regional networks • Tier-3: local Internet service provider

8. Internet Infrastructure • Location where a network (ISP, corporate network, or regional network) gets access to the Internet is called a Point-of-Presence (POP). • Locations (Tier-1 or Tier-2) networks are connected for the purpose of exchanging traffic are called peering points. • Public peering: Traffic is swapped in a specific location, called Internet exchange points (IXPs) • Private peering: Two networks establish a direct link to each other.

9. Topology of a Tier-1 NSP

10. Organization of a single node in a Tier-1 network

11. Who is Who on the Internet ? • Internet Society (ISOC):Founded in 1992, an international nonprofit professional organization that provides administrative support for the Internet. Founded in 1992, ISOC is the organizational home for the standardization bodies of the Internet. • Internet Engineering Task Force (IETF): Forum that coordinates the development of new protocols and standards. Organized into working groups that are each devoted to a specific topic or protocol. Working groups document their work in reports, called Request For Comments (RFCs). • IRTF (Internet Research Task Force):The Internet Research Task Force is a composed of a number of focused, long-term and small Research Groups. • Internet Architecture Board (IAB): a technical advisory group of the Internet Society, provides oversight of the architecture for the protocols and the standardization process • The Internet Engineering Steering Group (IESG): The IESG is responsible for technical management of IETF activities and the Internet standards process. Standards. Composed of the Area Directors of the IETF working groups.

12. Internet Standardization Process • Working groups present their work i of the Internet are published as RFC (Request for Comments). RFCs are the basis for Internet standards. • Not all RFCs become Internet Standards ! (There are >3000 RFCs and less than 70 Internet standards) • A typical (but not only) way of standardization is: • Internet Drafts • RFC • Proposed Standard • Draft Standard (requires 2 working implementation) • Internet Standard (declared by IAB)

13. Assigning Identifiers for the Internet • Who gives the university the domain name “www.mdurohtak.com” • Who assigns it the network prefix “128.143.0.0/16”? • Who assigns port 80 as the default port for web servers? • The functions associated with the assignment of numbers is referred to as Internet Assigned Number Authority (IANA). • IANA used to be managed by Jon Postel at ISI • Since the 1990s, IP addresses and domain name allocation are delegated to independent organizations. Different organizations are responsible for allocating domain names and IP addresses

14. The IANA Function • The functions associated with the assignment of numbers in the Internet is referred to as Internet Assigned Number Authority (IANA). • IANA serves as a registry that keeps records of assigned numbers: • IP addresses • Protocol numbers • Domain names (until 1992) • There is no charge for allocation.

15. Regional Internet Registries (RIRs) • Registration and management of IP address is done by Regional Internet Registries (RIRs) • Where do RIRs get their addresses from: IANA maintains a high-level registry that distributes large blocks to RIRs • RIR are administer allocation of: • IPv4 address blocks • IPv6 address blocks • Autonomous system (AS) numbers • There are currently 4 RIRs worldwide: • APNIC (Asia/Pacific Region), • ARIN (North America and Sub-Sahara Africa), • LACNIC (Latin America and some Caribbean Islands) • RIPE NCC (Europe, the Middle East, Central Asia, and African countries located north of the equator). • A fifth regional registry (AfriNIC) is in formation for Africa.

16. Transitioning of Domain Name Registration • Until 1992: Domain name registration done as part of IANA • 1992: InterNIC was created in a partnership between US government and companies to organize and maintain the growing DNS registry and services. The company Network Solutions ran the administration of InterNIC. Until 1998, Network Solutions had a monopoly for domain names. • 1995: InterNIC started harging for domain names ($100 for 2 years) • 1997: President Clinton directs the Secretary of Commerce to privatize the management of the domain name system (DNS) in a manner that increases competition and facilitates international participation in its management. • 1998: ICANN was created in response to a policy statement issued by the US Department of Commerce that called for the formation of a private sector not-for-profit Internet stakeholder to administer policy for the Internet name and address system. ICANN operates under a renewable 3-year contract with the US Department of the Commerce. • ICANN accredits domain-name registrar for .com, .org., .net (and other domain)

17. ICANN • The Internet Corporation for Assigned Names and Numbers (ICANN) is an internationally organized, non-profit corporation that has responsibility for Internet Protocol (IP) address space allocation, protocol identifier assignment, Top-Level Domain name system management, and root server system management functions. • ICANN performs the IANA functions • ICANN accredits domain-name registrar for .com, .org., .net (and other domain) • Since ICANN performs the IANA functions, it is in charge for allocating all numbers. However, the main concern is the allocation of domain names. • ICANN role is to oversee the domain-name registration system's transition from government hands to private hands and to coordinate its decentralization and the integration into a global community.

18. Modes of Connecting to the Internet Two Modes of Connectivity • On Demand Connection • Dedicated Connection

19. Dial Up Connection Dial-up Internet Access is a form of Internet access via telephone lines. The user's computer uses an attached modem connected to a telephone line to dial into an Internet service provider's (ISP) node to establish a modem-to-modem link, which is then used to route Internet Protocol packets between the user's equipment and hosts on the Internet. Dial-up connections to the Internet require no infrastructure other than the telephone network. As telephone access is widely available, dial-up remains useful to travelers

20. Dial Up Connection Dial-up access is a transient connection, because either the user or the ISP terminates the connection. Internet service providers will often set a limit on connection durations to prevent hogging of access, and will disconnect the user — requiring reconnection and the costs and delays associated with it. Performance Modern dial-up modems typically have a maximum theoretical transfer speed of 56 kbit/s. Dial-up connections usually have latency as high as 400 ms or even more, which can make online gaming or video conferencing difficult, if not impossible. An increasing amount of Internet content such as streaming media will not work at dialup speeds

21. List of dialup speeds Modem 110 baud 0.1 kbit/s Modem 300 (300 baud) 0.3 kbit/s Modem 1200 (600 baud) 1.2 kbit/s Modem 2400 (600 baud) (V.22bis) 2.4 kbit/s Modem 2400 (1200 baud) (V.26bis) 2.4 kbit/s Modem 4800 (1600 baud) (V.27ter) 4.8 kbit/s Modem 9600 (2400 baud) (V.32) 9.6 kbit/s Modem 14.4 (2400 baud) (V.32bis) 14.4 kbit/s Modem 28.8 (3200 baud) (V.34) 28.8 kbit/s Modem 33.6 (3429 baud) (V.34) 33.6 kbit/s Modem 56k (K56flex) 56.0/33.6 kbit/s Modem 56k (X2_(protocol) 56.0/33.6 kbit/s Modem 56k (8000/3429 baud) (V.90) 56.0/33.6 kbit/s Modem 56k (8000/8000 baud) (V.92) 56.0/33.6 kbit/s Hardware compression (variable) (V.90/V.42bis) 56.0-220.0 kbit/s Hardware compression (variable) (V.92/V.44) 56.0-320.0 kbit/s Server-side web compression (variable) 100.0-1000.0 kbit/s

22. Using compression to exceed 56k Today's V.42, V.42bis and V.44 standards allow the modem to accept data at a port rate faster than its line rate would imply. That is, rather than actually transmit the data given it by the source, it transmits a compressed version of that data. For instance, a 53.3 kbit/s connection with V.44 can transmit up to 53.3*6 == 320 kbit/s if the offered data stream can be compressed that much. One problem is that the compression tends to vary continuously, due to the transfer of already-compressed files (ZIP files, JPEG images, MP3 audio, MPEG video). At some points the modem will be sending compressed files at approximately 50 kbit/s, uncompressed files at 160 kbit/s, and pure text at 320 kbit/s, or any value in between.

23. Compression by the ISP ISP uses a compression program that squeezes images, text, and other objects at the server, just prior to sending them across the phone line. The server-side compression operates much more efficiently than the "on-the-fly" compression of V.44- enabled modems. Typically website text is compacted to 5% thus increasing effective throughput to approximately 1000 kbit/s, and images are lossy-compressed to 15-20% increasing throughput to about 350 kbit/s. The drawback of this approach is a loss in quality, where the graphics acquire more compression artifacts taking-on a blurry appearance, however the speed is dramatically improved and the user can manually choose to view the uncompressed images at any time. The ISPs employing this approach advertise it as "DSL speeds over regular phone lines" or simply "high speed dialup".

24. Replacement by broadband Broadband in telecommunications refers to a signaling method that includes or handles a relatively wide range of frequencies, which may be divided into channels or frequency bins. Broadband is always a relative term, understood according to its context. The wider the bandwidth, the greater the information-carrying capacity. Broadband in data communications can refer to broadband networks or broadband Internet and may have the same meaning as above, so that data transmission over a fiber optic cable would be referred to as broadband as compared to a telephone modem operating at 56,000 bits per second.

25. DSL DSL is a family of technologies that provides digital data transmission over the wires of a local telephone network. DSL originally stood for digital subscriber loop, although in recent years, the term digital subscriber line has been widely adopted as a more marketing-friendly term for ADSL, which is the most popular version of consumer-ready DSL. DSL can be used at the same time and on the same telephone line with regular telephone, as it uses high frequency, while regular telephone uses low frequency. Typically, the download speed of consumer DSL services ranges from 256 kilobits per second (kbit/s) to 24,000 kbit/s, depending on DSL technology, line conditions and service level implemented.

26. Asymmetric Digital Subscriber Line (ADSL) Asymmetric Digital Subscriber Line (ADSL) is a form of DSL, a data communications technology that enables faster data transmission over copper telephone lines than a conventional voiceband modem can provide. It does this by utilizing frequencies that are not used by a voice telephone call. A splitter - or microfilter - allows a single telephone connection to be used for both ADSL service and voice calls at the same time.

27. Cable Modem A cable modem is a type of modem that provides access to a data signal sent over the cable television infrastructure. Cable modems are primarily used to deliver broadband Internet access in the form of cable internet, taking advantage of the high bandwidth of a cable television network. They are commonly found in Australia, Canada, Europe, Costa Rica, and the United States.

28. Optical Fiber Connectivity Optical fiber can be used as a medium for telecommunication and networking because it is flexible and can be bundled as cables. It is especially advantageous for long-distance communications, because light propagates through the fiber with little attenuation compared to electrical cables. This allows long distances to be spanned with few repeaters. Additionally, the per-channel light signals propagating in the fiber can be modulated at rates as high as 111 gigabits per second, although 10 or 40 Gb/s is typical in deployed systems.

29. The ISP An Internet service provider (ISP, also called Internet access provider or IAP) is a company that offers its customers access to the Internet. The ISP connects to its customers using a data transmission technology appropriate for delivering Internet Protocol datagrams, such as dial-up, DSL, cable modem or dedicated high-speed interconnects. • Virtual ISP A Virtual ISP (VISP) is an operation which purchases services from another ISP (sometimes called a "wholesale ISP" in this context which allow the VISPs customers to access the Internet using services and infrastructure owned and operated by the wholesale ISP. • Free ISP Free ISPs are Internet Service Providers (ISPs) which provide service free of charge. Many free ISPs display advertisements while the user is connected; like commercial television, in a sense they are selling the users' attention to the advertiser. Other free ISPs, often called freenets, are run on a nonprofit basis, usually with volunteer staff. There are also free shell providers and free web hosts.

30. Internet Protocol • The Internet Protocol (IP) is a protocol used for communicating data across a packet-switched internetwork using the Internet Protocol Suite, also referred to as TCP/IP. • IP is the primary protocol in the Internet Layer of the Internet Protocol Suite and has the task of delivering distinguished protocol datagrams (packets) from the source host to the destination host solely based on their addresses. For this purpose the Internet Protocol defines addressing methods and structures for datagram encapsulation. The first major version of addressing structure, now referred to as Internet Protocol Version 4 (IPv4) is still the dominant protocol of the Internet, although the successor, Internet Protocol Version 6 (IPv6) is being actively deployed worldwide.

31. Domain Name System What Is DNS? • DNS stands for Domain Name System.The primary purpose of DNS, whichconsists of a set of specified naming rules and implementation standards, is toprovide host name resolution. • Host name resolution is the process of resolving a computer’s user-friendlyhost name (such as www.idgbooks.com) to the numerical IP address of that computer. The reason host name resolution is important is becauseTCP/IP-based applications and utilities, such as Web browsers, use IPaddresses to communicate with other computers, while users prefer to use easily remembered host names to access other computers.

32. Domain Name System • DNS is implemented as a hierarchical structure often called the DNS domainnamespace.The trees and subtrees that make up the DNS domain namespace are called DNS domains. The DNS domain namespace is graphically represented as an inverted tree structure, with the root of the tree at the top. • The DNS domain at the top (or root) of the tree is called the rootdomain. It is often represented by a period (.). • The DNS domains directly under the root domain are called top-level domains.

33. Domain Name System • com Commercial organizations, such as pepsi.com • gov Government organizations, such as whitehouse.gov • mil Military organizations, such as army.mil • edu Educational organizations, such as stanford.edu • net Internet service providers, such as nsf.net • org Nonprofit organizations, such as metmuseum.org • xx Domains within a specific country, where each country is represented by a two-letter code, such as cbc.ca (where ca stands for Canada

34. Domain Name System • The DNS domains in the next level down, under top-level domains, are called second-level domains. • These domains are subdomains of top-level domains. Many businesses have a second-level domain that is a subdomainof the com domain, such as microsoft.com. Each person or organization using a second-level domain on the Internet is responsible for registering that unique DNS domain name with the appropriate authority—the appropriate authority being the one that manages the top-level domain containing the second-level domain.

35. Domain Name System • DNS domain names (also called fully qualified domain names [FQDNs]) • can contain a maximum of 63 characters. Allowed characters include uppercase letters (A–Z), lowercase letters (a–z), numbers (0–9), and the hyphen (-). Periods are used to separate domain and subdomain names, for