Outcomes

1. Outcomes • TCP/IP & OSI • LAN & WAN • IP address • Internet Connection Types • Internet Devices • DNS

2. What is TCP/IP? TCP/IP - (Transmission Control Protocol / Internet Protocol) The protocols, or conventions, that computers use to communicate over the Internet.2

3. TCP/IP 4-Layer Model • Application Layer: provides a wide range of services to network users. • Transport Layer: provides an end-to-end data delivery service that application processes use to exchange messages over the internet. • Internet Layer: provides routing and relaying functions for carrying packets of data from a source system to a destination system through an internet. • Link Layer: The main function of the network interface layer is to handle hardware-dependent functions and to present a standardized interface to the Internet layer of TCP/IP.

4. Layer 4: Application Layer Layer 3: Transport Layer Layer 2: Internet Layer Layer 1: Link Layer TCP/IP 4-Layer Model (DoD)

5. Ping Telnet FTP SMTP Traceroute DNS NFS TCP UDP ICMP IP IGMP RARP ARP Data Link media TCP/IP Protocol Suite

6. OSI 7-Layer Model (ISO) Layer 7: Application-specific protocols such as FTP and SMTP (electronic mail) Layer 6: Common formats for representation of data Layer 5: Management of sessions such as login to a remote computer Layer 4: Reliable delivery of data between computers Layer 3: Address assignment and data delivery across a physical network Layer 2: Format of data in frames and delivery of frames through network interface Layer 1: Basic network hardware - such as RS-232 or Ethernet

7. Data Application Application APDU AH Data Presentation PPDU PH Data Presentation SPDU Session Data Session SH TPDU Transport Transport TH Data Packet Network NH Network Data Frame Data Link Data Link DH DT Data Bit Bits Physical Physical The OSI Reference Model

8. OSI Seven-Layer Model • The Application Layer describes how real work actually gets done. Ex: this layer would implement file system operations. • The Presentation Layer describes the syntax of data being transferred. Ex: this layer describes how floating point numbers can be exchanged between hosts with different math formats. • The Session Layer describes the organization of data sequences larger than the packets handled by lower layers. Ex: this layer describes how request and reply packets are paired in a remote procedure call. • The Transport Layer describes the quality and nature of the data delivery. Ex: this layer defines if and how retransmissions will be used to ensure data delivery. • The Network Layer describes how a series of exchanges over various data links can deliver data between any two nodes in a network. Ex: this layer defines the addressing and routing structure of the Internet. • The Data Link Layer describes the logical organization of data bits transmitted on a particular medium. Ex: this layer defines the framing, addressing and checksumming of Ethernet packets. • The Physical Layer describes the physical properties of the various communications media, as well as the electrical properties and interpretation of the exchanged signals. Ex: this layer defines the size of Ethernet coaxial cable, the type of BNC connector used, and the termination method.

9. Local Area Network (LAN) Ring Bus Star

10. Router LAN Host Subnet Wide Area Network (WAN)

11. Class Range A 0.0.0.0 to 127.255.255.255 B 128.0.0.0 to 191.255.255.255 C 192.0.0.0 to 223.255.255.255 D 224.0.0.0 to 239.255.255.255 E 240.0.0.0 to 255.255.255.255 Internet Address Loopback: 127.0.0.0 to 127.255.255.255 Private: 192.168.0.0 to 192.168.255.255

12. 7 bits 24 bits Class A 0 netid hostid 16 bits 14 bits Class B 1 0 netid hostid 8 bits 21 bits Class C 1 1 0 netid hostid 28 bits Class D 1 1 0 1 Multicast group ID 28 bits Class E 1 1 1 1 (Reserved for future use) Internet Address InterNIC (rs.internic.net)

13. Internet Connection Types Connect to the Internet through: modem local-area network cable modem Digital Subscriber Line(DSL) connection. DSL is a very high-speed connection that uses the same wires as a regular telephone line.

14. More definitions of DSL… DSL ( Digital Subscriber Line ) is a method of high-speed data transfer over ordinary copper telephone lines. xDSL refers to different variations of DSL, such as ADSL, HDSL, SDSL and RADSL. *homework: find out what the above acronyms means!

15. GATEWAY A system (hardware-software combination) that links otherwise incompatible networks to communicate with one another. The term often refers to the server computer that links a LAN to the Internet.

16. Router Central switching device in a packet-switched network that directs and controls (routes) the flow of data. A traditional router routes packets within a single address NAT router directs datagrams between different address realms. NAT router sits on the border between two adress realms and performs such "transparent routing" by modifying addresses in IP headers, so that when packets enter another address realm they can be valid and routed properly. Routers are differentiated from data communications switches by the ability to perform higher-level functions necessary to the interconnection of different networks. NOW, What is NAT???

17. Network Address Translation NAT (Network Address Translation) is an IETF standard that enables LANs to use one set of private IP addresses for internal traffic an another set of IPs for external traffic. A NAT device makes all IP address translations where the LAN meets the WAN. NAT permits a large number of LAN users to share one external IP address, and adds some network security, since private IP address ranges are not routable outside the LAN.

18. NAT continued The following 3 blocks of the IP address space have been reserved by the Internet Assigned Numbers Authority (IANA) for private Intranets: 10.0.0.0 - 10.255.255.255 (class A, 10/8 prefix) 172.16.0.0 - 172.31.255.255 (class B range, 172.16/12 prefix) 192.168.0.0 - 192.168.255.255 (class C range, 192.168/16 prefix)

19. ETHERNET Is an IEEE data communications protocol originally developed for premises and local access networks (IEEE 802.3). It was originally developed for peer-to-peer communications using shared media over relatively short distances. Ethernet has been substantially improved over the years and now operates in a wide variety of settings. Ethernet is currently the most widely deployed LAN protocol in the world. Some of the newer variants of the standard include;Fast Ethernet - Ethernet at 100 Megabits per second.Gigabit Ethernet (Gig-E) - Ethernet at 1000 Megabits per second.

20. bandwidth Is the amount of data that can be carried in a given time period over a network. More technically, bandwidth is the width of the range of frequencies that an electronic signal occupies on a given transmission medium. In digital systems, bandwidth is usually expressed as bps (bits per second), Kbps (Kilobits/second or Mbps (Megabits / second). In analog systems, it's the number of cycles of change per second, or hertz.

21. What is the Domain Name System? The Domain Name System (DNS) helps users to find their way around the Internet. Every computer on the Internet has a unique address – just like a telephone number – which is a rather complicated string of numbers. It is called its "IP address" (IP stands for "Internet Protocol").

22. Domain Name But it is hard to remember everyone's IP address. The DNS makes it easier by allowing a familiar string of letters (the "domain name") to be used instead of the arcane IP address. So instead of typing 192.0.34.65, you can type www.icann.org. It is a "mnemonic" device that makes addresses easier to remember.

23. Domain Name Translating the name into the IP address is called "resolving the domain name.” The goal of the DNS is for any Internet user any place in the world to reach a specific website IP address by entering its domain name. Domain names are also used for reaching e-mail addresses and for other Internet applications.

24. Homework!!!! You can do this in the lab Read the below sites: http://computer.howstuffworks.com/wireless-network2.htm http://www.webopedia.com/TERM/8/802_11.html http://searchmobilecomputing.techtarget.com/sDefinition/0,,sid40_gci783003,00.html

25. Resources to look-up • http://www.cisco.com/univercd/cc/td/doc/product/iaabu/centri4/user/scf4ap1.htm • http://www.getnetwise.org/glossary.php • W. Stallings, Data & Computer Communications, (6th Edition), Prentice Hall,2000 • http://www.pcsupportadvisor.com/nasample/t04124.pdf