Introduction to TCP/IP

1. Introduction to TCP/IP Profession Development CourseNVCC Instructors and Staff Presented by Lori Krist, Faculty NVCC Woodbridge December 2006

2. Welcome • Goals and assumptions • No deep networking knowledge is assumed • Wide overview, shallow depth • Components of this class • Overview of TCP/IP, networking, Internet • IP addressing and IP layer protocols • Transport Layer protocols TCP and UDP • Basic TCP/IP Services (FTP, telnet, etc) • DNS • Basic Routing • IPv6 • Software utilities to see inside your network

3. Internet Background • Before the Internet, there were only limited, direct point to point links between mainframe computers. • Advance Research Projects Agency (ARPA - later Defense ARPA) began a funding project, in 1966, to explore Internetworking built around Packet Switching. • In 1969, a four node experimental system, ARPANET, was created. • In May 1973, the first Ethernet operation occurred at the Xerox Palo Alto Research Center. • In May 1974 Vinton G. Cerf and Robert E. Kahn proposed a design that formed the basis for the Internet Protocol (IP) and the Transmission Control Protocol (TCP). • In 1975 ARPANET was converted from an experimental to an operational network and The Defense Communication Agency (DCA), which later became the Defense Information System Agency (DISA), was given responsibility for administering the network. • In 1978 the DoD declared TCP/IP the MILSTD for its data communication networks. • In 1985 the National Science Foundation Net (NSFNET) was incorporated as the high-speed backbone to interconnect research sites and supercomputer facilities. An infrastructure of Regional Service Providers began to be built around this backbone. • Between 1987-1991 a mesh of interconnected service providers replaced the Internet backbone.

4. Internet Design Principles • The design intent of the ARPANET was to overcome the vulnerability of a circuit switched network due to an intermediate node or central failure. • In order to overcome this vulnerability, a design based upon a packet switching network was proposed. • The packet switching concept was based upon several design principles that led to new network design paradigm. • Packet switching provides several advantages over a circuit-switched network • The low cost resources lead to a larger more tightly connected network with redundant paths. • The network resources, rather than being dedicated could be shared among many communication pairs. • Variable data rates could be linked due to the intermediate node store-and-forward capability (in memory).

5. Internet Design Principles • Principle One: There are no dedicated resources between the sender and the receiver. • A side effect of this principle is that there is no resource guarantee. • Principle Two: Packets can travel any route across the network between communication pairs. • This principle facilitates fast packet forwarding but has the side effect of that no single network node knows the complete route between communication pairs. • Principle Three: Different network links can have different rates. • A side effect of this design principle is that high-bandwidth core links can overwhelm low-bandwidth edge links. • Principle Four: The network will provide a best-effort service model in that all packets will be treated equally. • This led to low-cost simple routers focused on traffic forwarding only. • Principle Five: The end-to-end paradigm is that application specific requirements such as error detection and packet reordering would be handled by the communication pairs. • This had the side effect of making the edge devices responsible for security functions.

6. Layered Network Models • Breaks up the networking process into a series of interconnected and interrelated subproblems, or layers. The concept of layers is used to describe communication from one computer to another. • These layers operate more or less independently of each other, enabling modular design, and modular implementation. Individual layers encapsulate specific, mostly independent functions. Changes to one layer to do not affect another. • Completely separates the hardware from the software. Each layer has a special function. • Each layer depends on the layers below, each layer provides service to the layer above. • Several layered models exist –TCP/IP, Xerox, AppleTalk, Banyan Vines • The information that travels on a network is generally referred to as data or a packet • A packet is a logically grouped unit of information that moves between computer systems. • As the data passes between layers, each layer adds additional information that enables effective communication with the corresponding layer on the other computer.

7. OSI Reference ModelInternational Organization for Standardization Open Systems Interconnection • A standard way to explain and compare network operations. • The Open System Interconnection (OSI) reference model was released in 1984 by the ISO. It breaks network communication into seven layers. • It provided vendors with a set of standards that ensured greater compatibility and interoperability among various network technologies produced by companies around the world. • Considered the best tool for teaching people about sending and receiving data on a network.

8. OSI Reference Model • For data to travel from the source to the destination, each layer of the OSI model at the source must communicate with its peer layer at the destination. This is called peer-to-peercommunication • The protocols of each layer exchange information, called protocol data units (PDUs)

9. Source Destination DATA Application Application Presentation Presentation DECAPSULATION Session Session ENCAPSULATION SEGMENT Transport Transport PACKET Network Network FRAME Data-Link Data-Link BITS Physical Physical 0101010101010101010

10. TCP/IP and Networks • Protocol – a collection of designated practices, policies and procedures. In networks, they are the set of rules for how data should be transmitted across a connection. • TCP/IP is a set of protocols for connecting computers to the Internet, a suite or stack. • TCP/IP is a transport to carry data and the rules for how data should move. TCP/IP also has a set of applications for basic tasks needed with connectivity – file transfers, signing on to remote computers, etc. • TCP/IP ties networks and Internet together regardless of the hardware and software used to build those networks. • Data moves in small chunks called packets. TCP/IP makes sure data does not get ruined when split into packets and is put correctly back together again.

11. The TCP/IP ModelThe Core Protocol of the Internet • IP can be thought to point the way for the packets, while TCP provides a reliable transport • TCP is a connection-oriented protocol. It maintains a dialogue between source and destination Handles issues of representation, encoding, and dialog control Handles quality of service issues of reliability, flow control, and error correction. Divides TCP segments into packets and send them from any network. Best path determination and packet switching Host-to-network layer, concerned with all of the components, both physical and logical, that are required to make a physical link. Developed by DoD. Designed to provide reliable data transmission to any destination on the network under any circumstances.

12. TCP/IP is a Family of Protocols • The protocols in the suite move data from one layer to another and interact with one another. • The core of IP works with Internet addresses (much more on that coming up). • TCP uses IP to deliver packets to upper layer applications, and provides a reliable data stream between computers

13. Standards Groups Managing TCP/IP • No one is in charge of the Internet, although TCP/IP falls under the purview of several standards-making bodies. TCP/IP is in the public domain because it has been funded with public monies – everybody and nobody owns TCP/IP! • ISOC: The Internet Society. Parent organization for various Internet boards and task forces. International and non-profit. • IAB: Internet Architecture/Activities Board. The arm of ISOC that provides oversight for architecture for all Internet protocols and procedures, and editorial oversight for RFC documents Chairman of the IAB is called the Internet Architect. • IETF: Internet Engineering Task Force. This group drafts, tests, proposes and maintains official Internet standards in the form of RFC’s, concentrating on engineering problems. Two major groups: • IESG: Internet Engineering Steering Group • IESG Working Groups – examine specific engineering problems

14. Standards Groups Managing TCP/IP • ICANN: Internet Corporation for Assigned Names and Numbers. Responsible for the global coordination of the Internet's system of unique identifiers - Internet domain names, network addresses, protocol parameters and behaviors. Oversees IP registration but delegates to commercial authorities. Designed to replace IANA Internet Assigned Numbers Authority. ISPs obtain allocations of IP addresses from a local Internet registry (LIR) or national Internet registry (NIR), or from their appropriate Regional Internet Registry (RIR). The IANA's role is to allocate IP addresses. When an RIR requires more IP addresses for allocation or assignment within its region, the IANA makes an additional allocation to the RIR. AfriNIC (African Network Information Centre) - Africa Region APNIC (Asia Pacific Network Information Centre) - Asia/Pacific Region ARIN (American Registry for Internet Numbers) - North America Region LACNIC (Regional Latin-American and Caribbean IP Address Registry) – Latin America and some Caribbean Islands RIPE NCC (Réseaux IP Européens) - Europe, the Middle East, and Central Asia

15. ICANN Structure Regional Internet Registries -ARIN-RIPE-APNIC-LACNIC-AFRNIC Generic Top Level Domain Registrars -Intellectual Property-ISPs-Businesses-Universities-Consumers Country Code Top Level Domain Registries .us, .uk, .au, etc

16. Internet Architecture vBNS (IP over ATM on SONET) Super Computer Centers 1.Cornell Theory Center (CTC). 2. National Center for Atmospheric Research (NCAR). 3. National Center for Supercomputing Applications (NCSA). 4. Pittsburgh SuperComputing Center (PSC). 5. San Diego SuperComputing Center (SDSC). RA NAP (PAC Bell) San Francisco, Ca NAP (Ameritech) Chicago, Ill NAP (Sprint) Pennsauken, NJ NAP (MAE-East) Washington,DC Other National Networks SprintLink Regional Network Provider SPRINT Regional Provider ANSnet Internet MCI BBN Regional Network MCI Regional Provider AOL Regional Provider Commercial Networks ANS Regional Network Regional Network Provider Government Networks Consumers vBNS - Very High Speed Backbone Network System NAP - Network Access Point (also called Public Internet Exchange Points). MAE - Metropolitan Area Ethernet ISP - Internet Service Provider(approx 4500) Global ISP (Concentric, IBM, etc) National ISP (AT&T Worldnet, Mindspring, AOL, MSM, Prodigy, etc). Regional ISP (Ameritech, Bellsouth, Bell Atlantic,US West, etc). Local ISP (Inuvik TV, Qwest, etc). ANS - Advance Network and Services(subsidiary of AOL). RA - Routing Arbiter IRR - Internetworking Routing Registries RIPE Routing Registry MCI Routing Registry CA*net Routing Registry ANS Routing Registry Routing Arbiter Database JIPRR Routing Registry

17. Router Router Router Router Internet Backbone Network A Network B Internet Backbone Network C Network D

18. Internet Backbone • This superfast network spanning the world from one major metropolitan area to another is provided by a handful of national Internet service providers (NSPs). These organizations use connections running at approximately 45 mbps (T3 lines or DS3) linked up at specified interconnection points called national access points (which are located in major metropolitan areas). Regiona and then local ISPs connect to this backbone through routers so that data can be carried though the backbone to its destination. • National Service Providers (NSP) • Provide connectivity to Regional Network Providers and large ISPs • Verizon(UUNet), AT&T, Qwest, Sprint Nextel, British Telecom, SAVVIS, etc • Network Access Points (NAP) are where NSP and ISP interconnect

19. One Provider’s Backbone

20. Hierarchy of ISP High-Speed Backbone Network Access Points Internet Exchange Points MAE EastMetro Area Exchange MAE West PAC Bell Peering Peering Peering National/ Regional ISPs UUNET Mindspring PSInet AOL Local ISPs Organizations

21. Router Router Router Router Modem ISPs, POPs and NAPs Local ISP POP Regional POP NAP Regional POP Local ISP POP Router Router Router Router Router Router Router • Tier 1 providers (National ISPs) have national backbones, over1,000,000 subscribers connect to a National Access Points (NAP). • Tier 2 ISPs buy Internet connectivity from Tier 1 providers, have local and regional backbones and generally have over 50,000 subscribers. • Tier 3 ISPs obtain their bandwidth from Tier 2s, provide local service and generally have less than 50,000 subscribers. • Residential or Remote users normally connect to the local ISPs Point of Presence (POP). Remote Corporate

22. Typical ISP Backbone Router POP Router Washington Site FR Switch Backbone Router ISP FR ISP FR • Tier 1 providers own and operate national networks. • National ISPs connect at either NAPs or Peering Points. • Connection is a minimum of DS-3 (45 Mbps). Backbone Router Backbone Router ISP FR ISP FR ISP FR Backbone Router Router FR Switch POP Baltimore Site Router

23. Router Typical ISP POP ISP POP Remote Broadband Network PSTN Switch ISP Backbone SOHO ISDN Switch Internet DS0 – DS3 WEB, Mail, News, RADIUS, etc Network Management Console Corporate

24. END OF LECTURE