Internet Architecture. Course: CIS 3003 Fundamental of Information Technology. History. October 29, 1969 - The first ARPANET link established. APRANET is a network developed by Advanced Research Projects Agency in Department of Defense.
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Internet Architecture Course: CIS 3003 Fundamental of Information Technology
History • October 29, 1969 - The first ARPANET link established. APRANET is a network developed by Advanced Research Projects Agency in Department of Defense. • During 1960’s, packet switching developed. Data divided into small packets, each of which can take different paths and thus have no central point of failure.
History • On January 1, 1983, TCP/IP protocols became the only approved protocol on the ARPANET. TCP developed in 1970’S • In 1989, World Wide Web and HTML developed by Tim Berners-Lee at CERN. • January 23, 1993, first Internet browser called Mosaic was released by Marc Andreessen and Eric Bina, students at NCSA in UIUC.
History • In 1995, first VoIP software was released by Vocaltec. Same year, Intel, Microsoft, Radvision initiated standardization for VoIP. • In 1999, first peer-to-peer music file sharing program, Napster, released by John and Shawn Fanning. In July 2001, the company is shut down to comply with court ruling.
History • In 1999, Wi-Fi Alliance and its trademark formed. • On October 1, 2001, first commercial 3G cellular network launched by NTT DoCoMo in Japan. Higher bandwidth provided applications such as mobile TV, video on demand, and location-based services.
History • In August 2003, Myspace (a social networking website) launched. A person can post status, create groups, post videos, chat with friends. • In February 2004, Facebook launched. More people visited Facebook than Google for the week ending March 13, 2010. Facebook has 800 million accounts; U.S. population 300 millions. • In February 2005, YouTube launched. User can upload own video. Bought by Google in 2006. • In July 2006, Twitter launched. 140 characters short messages.
Internet Backbone and Provider • Internet backbone – high capacity trunk • Network service providers: AT&T, Qwest, Verizon, etc.
Routing • Data divided into smaller segments called packet. • Each packet can take different path to and gets reassembled at destination. • Routing table is used to direct data packets to a destination. • Packets reach a destination hop by hop. • Routing protocols are used to form routing table.
Routing • Data divided into smaller segments called packet. • Each packet can take different path to and gets reassembled at destination. • Routers direct packets toward a destination. Each router passed is a hop.
Routing Table • Routing table is used to direct data packets to a destination. • Network mask reduces number of entries; destinations in same subnet need one entry.
Routing Protocol • Routing protocols are used to form routing table. Ensures loop free. • Interior gateway routing via link-state • Interior gateway routing via distance vector • Exterior gateway routing.
Interior Gateway Routing Link State • Only connectivity and characteristics of a physical link are used to determine the metric values. • OSPF, IS-IS Distance Vector • Hop count and other information including bandwidth, delay, load, maximum transmission rate of a medium, and performance reliability. • RIP, IGRP and EIGRP
Exterior Gateway Routing • Allow an internal network to connect to other networks. • BGP v4 is the routing protocol used by the public Internet. • IETF RFC1771 • Till late 2001, global routing table entries grow exponentially. Exponential growth of routing table entries
IP Address • IP: Internet Protocol • IETF RFC 791 • An IP address is assigned to any device connected to a network. • The address is logical and not depend on the hardware device.
IP v4 • Each address has 32 bits • 01011110000101001100001111011100 • Dotted Decimal Format • 01011110 00010100 11000011 11011100 • 126.96.36.199 • 32 bits theoretically provides 4,294,967,296 (calculated as 232) unique addresses. However, actual usable addresses are less.
IP v4 Classes • IP address is hierarchical • An organization such as university or Internet service provider can apply for a chunk of IP addresses with Internet Assigned Numbers Authority (IANA) • Class A, Class B, Class C, and Classless • Class D (multicast) and Class E (reserved) are not used.
Class A • Most significant bit set to 0 • Next 7 bits indicate network number • Maximum 128 Class A networks. • Next 24 bits identifies a host in the network. • 16,777,216 addresses per Class A block • Range: 0.0.0.0 - 127.255.255.255 • Organization has a Class A address block: • IBM, US DoD, Apple Inc.
Class B • Most two significant bits set to 10 • Next 14 bits indicate network number • Maximum 16,384 Class B networks. • Next 16 bits identifies a host in the network. • 65,536 addresses per Class B block • Range: 188.8.131.52 – 184.108.40.206 • Organization has a Class B address block: • University of Central Florida.
Class C • Most three significant bits set to 110 • Next 21 bits indicate network number • Maximum 2,097,152 Class C networks!!! • Next 8 bits identifies a host in the network. • 256 address per Class C block • Range: 192.0.0.0 – 220.127.116.11
IP v4 addresses exhaustion • An organization gets entire range of a block regardless whether it can use all the addresses. Any unused addresses cannot be allocated to other organizations. • Class B has too many addresses and Class C too little for a medium size company.
Classless • Delay the exhaustion of IP v4 addresses. • Explicitly state how many bits are used to identify a network. • An organization can get a block that is between Classes A and B or Classes B and C. • Format: • IPv4 block 192.168.0.0/22 represents the 232-22 or 1024 IPv4 addresses from 192.168.0.0 to 192.168.3.255.
Classless Inter-Domain Routing • CIDR reduces the number of routing table entries in the global routing table. • A Internet service provider can have one large IP block and may only need one entry in the global routing table to direct data packet to its users. • Routing entry of 192.168.100.1/24 matches to any address that has the same first 24 bits. This entry has equivalent network mask of 255.255.255.0.
IP v6 • Each address has 128 bits or 16 bytes • 1111110111011100 1010110000010000 1000000100110010 1011101000110010 0100111100010010 0001000001110000 1101110100010011 0110100100100001 • Hexadecimal Format • FDDC:AC10:8132:BA32:4F12:1070:DD13:6921 • 2128 or 3 1038possible addresses. • Human population: 6,775,235,700 or 6 109
Assignment 4 • http://www.cs.ucf.edu/~aho/cis3003/hw/ • A new version of Question 1 is posted. The assignment will be due on Friday 10/21/2011. • Chapters 8, 9 and 10 • Question 3 Example: • My iPhone 4S uses 3G cellular technology. Its wireless capability lets me call my friends and families any time I want.
Local IP v4 address • Defined in IETF RFC 1918. IANA has reserved following for private addresses: • 10.0.0.0 - 10.255.255.255 (10/8 prefix) or a single Class A address block. • 18.104.22.168 - 172.31.255.255 (172.16/12 prefix) or a single Class B address block. • 192.168.0.0 - 192.168.255.255 (192.168/16 prefix) or a single Class C address block. • An organization can use any other range as local addresses without apply with IANA.
Network Address Translation(NAT) • A NAT router translates a local unregistered IP address to an external registered IP address.
Network Address and Port Translation (NAPT) • RFC 2663. Multiple local computer share one registered IP address; each has its own port.
NAPT • Source/destination addresses specified in IP • Port specified in TCP header. NAT router needs to be aware of the protocol used in transport layer in addition to the network layer protocol.
NAT static and dynamic mapping Static • Maps a local address of a host to a fixed static registered address. • Allows an host such as a server to be accessed from outside. Dynamic • Maps a local address of a host to an available address from a range of registered addresses. • Could cause problems to applications such as P2P programs, VoIP, or online games where a host may receive an request from outside.
Domain Name System • Lets human user to enter alphanumeric strings that is easier to remember than the IP address of a website. • Google.com has an IP address of 22.214.171.124
Domain Name • www.google.com • Left most indicates top level domain • .com (for commercial businesses) • .org (for nonprofit organizations) • .edu (for educational institutions) • .gov (for the U.S. government) • .mil (for the U.S. military) • .net (for networks) • .int (for international entities) • .biz, .info, .coop, .museum, .name, .pro, and .aero
Domain Name • www.google.com • Left most indicates top level domain
Domain Name • www.google.com • Left to the top level domain is second level domain • google • Third level domain • www in www.google.com • maps in maps.google.com • state in www6.hsmv.state.fl.us, which has 5 levels.
Address resolution • Translate a human readable domain name string into a machine understandable IP addresses. • DNS is an enormous database management system distributed among numerous servers around the world.
Root Server • 13 root servers for entire Internet
Root Name Clusters • Each address may have several physical servers for reliability and faster access worldwide.
URL • Uniform Resource Allocator • Common network protocols include http, https, ftp. • Server domain name is not case sensitive while file path, name and format may be.
IP address allocation • Internet Assigned Numbers Authority (IANA) assigns blocks of IP v4 and v6 addresses to regional and national Internet registries that assign IP blocks to their local Internet registries.
Domains Name • IANA maintains a database of top level domain, root servers, and permitted unicode characters used in internationalized domain names (IDN). http://www.iana.org/ • Root Zone Database and whois.iana.org. • http://tools.ietf.org/html/rfc1591 describes appropriate organizations for a particular top level domain such as .edu • IDN Practices Repository • Example IDN: 上海市政府.CN
Open issue of IP address assigning • IANA was funded by United States Defense Advanced Research Projects Agency (DARPA) • Internet Corporation for Assigned Names and Numbers (ICANN), a private nonprofit organization was created on September 18, 1998, in response to a white paper by U.S. Department of Commerce. • The IANA, under the auspices of ICANN, still has centralized responsibility for the IP v4 and v6 address spaces.
Open issue of IP address assigningcont’d • Controversy of whether or not IANA is international enough and is a United States controlled entity. • In 2005, United Nation advocated United States to relinquish the control over a U.N. institution. • In response, U.S. assert its responsibility and oversight to IANA and argued possible negative effects of stability and security by the proposed change.
Open issue of domain name • Intellectual property right • united.com is currently held by United Airlines, but can United Van Lines argue to obtain the domain? • Can any organization with acronym PETA register peta.org? Cybersquatting • First amendment – Can someone register an offensive domain name? • How should an U.S. company registers its domain name in a foreign country? • Citi Bank in China? 花旗银行 orhuaqi yinhang
Open issues of Internet • Tax – Who collects the tax of financial transactions made over Internet? • Impact of security breach – Recent attacks of major credit card and bank websites affect millions of people. • Is Internet access a basic human right? United Nations thinks so. • Net neutrality – Quality of service and Tiered service.
US ZIP Code Map • 32816
Applications of Internet • Emails • Instant messages • World Wide Web • File Sharing – Peer-to-peer • VoIP • Online Video • Social Network.
E-Mail • E-mail is online alternative to postal mail. It is fast and convienent. • E-mail is a store and forward system that does not require the simultaneous online presence of senders and receivers
Email transfer protocols • A sender uses Simple Mail Transfer Protocol (SMTP) to send messages to an email server. • The sender’s email server uses SMTP to send the message to the receiver email server. • The receiver uses the Post Office Protocol (POP) or the Internet Message Access Protocol (IMAP) to retrieve the message.
Email message format • Multipurpose Internet Mail Extensions (MIME) • Allows an email contains non-ASCII character, non-text attachments, multiple parts of message • Allows message header contains non-ASCII characters. • Also used in HTML page
Instant Message • Faster text communication than email • No standard protocol. Each IM software uses its own protocol. • One-to-one or group communication • Popular IM software: Window Live Messenger, Google Talk, Yahoo Messenger, ICQ, etc. • Enterprise IM encrypts and archives conversation. Ex: Microsoft Lync (formerly Microsoft Office Communicator).