Networking operating systems are designed to provide network processes to clients and peers.

1. Networking operating systems are designed to provide network processes to clients and peers. • Network services include the World Wide Web (WWW), file sharing, mail exchange, directory services, remote management, and print services. • The most popular network processes rely on the TCP/IP suite of protocols.

2. What is Remote Access? • With a remote access connection, employees can access the corporate remote access server and log in to the network with their regular user account. • Employees can then use all the resources that would be available from the office desktop computer.

3. Terminal Emulation Services • Terminal emulation is the process of accessing a remote system via a local computer terminal. • The local terminal runs software that emulates, or mimics, the look of the remote system terminal. • The local user can type commands and execute programs on the remote system. • The most common terminal emulation application is Telnet, which is part of the TCP/IP protocol suite.

4. Telnet services • Telnet is the main Internet protocol for creating a connection with a remote machine. • It gives the user the opportunity to be on one computer system and do work on another. • Telnet has the following security considerations: • Hacking • Password guessing • Denial of Service (DoS) attacks • Packet sniffing (viewable text data)

5. Web Services • The Web is based on a client-server model. • Clients attempt to establish TCP sessions with web servers. • Once established, a client can request data from the server. • The Hypertext Transfer Protocol (HTTP) typically governs client requests and server transfers. • Web client software includes GUI web browsers, such as Netscape Navigator and Internet Explorer.

6. Domain Name Service (DNS) • The DNS protocol allows these clients to make requests to DNS servers in the network for the translation of names to IP addresses. • Hostnames and the DNS services that computer systems run are all linked together. • The Internet name that the DNS resolves to the IP address is also called the Hostname. • The first part of the hostname is called the Machine Name and the second part is called the Domain Name.

7. DHCP • Dynamic Host Configuration Protocol (DHCP) enables computers on an IP network to extract their configurations from the DHCP server. • These servers have no information about the individual computers until information is requested. • DHCP also allows for recovery and the ability to automatically renew network IP addresses through a leasing mechanism. • This mechanism allocates an IP address for a specific time period, releases it and then assigns a new IP address.

8. Definition. • Integrated hardware and software components with interconnecting media that facilitate communication between individual end systems. • LAN Local Area Network. • Main Focus for CCNA-1 • WAN Wide Area Network.

9. Network protocols Protocols control all aspects of data communication, which include the following: • How the physical network is built • How computers connect to the network • How the data is formatted for transmission • How that data is sent • How to deal with errors Examples • Institute of Electrical and Electronic Engineers (IEEE), • American National Standards Institute (ANSI), • Telecommunications Industry Association (TIA), • Electronic Industries Alliance (EIA) • International Telecommunications Union (ITU), formerly known as the Comité Consultatif International Téléphonique et Télégraphique (CCITT).

10. Connecting to the Network. • Addressing. • Source and Destination. • Local (Physical, MAC) • Global (Logical, IP). • Encapsulation. • Packaging of data. • Framing and frame formats. • Route selection. • Learning and maintenance of optimal routes.

11. Network Connectivity. • Physical Connection • Interface / Port. • NIC ( Network Interface Card ) / Network Adapter. • MAC Address, Unique physical address 48 bits long. • WAN interface. • Serial connection to service provider outlet. • Media • Co-Axial Cable. • Twisted Pair Cable, CAT5, CAT5e, CAT6, etc • Fibre-Optic Cable, Multi-Mode, Single-Mode. • Wireless • Infra-Red

12. Network Connectivity. • Logical Connection. • Addressing. ( IP ) • Control. ( TCP ) • Routing. • Encapsulation. • Framing • The de-facto standard for the Internet is the TCP/IP protocol suite.

13. Network Connectivity. • Network Applications. • http Hyper Text Transfer Protocol. • smtp Simple Mail Transfer Protocol. • dns Domain Name Service. • snmp Simple Network Management Protocol. • ftp File Transfer Protocol. • tftp Trivial File Transfer Protocol. • telnet • Etc, etc

14. Network Connectivity. CCNA Areas of interest. • LAN • Ethernet / IEEE 802.3 • FDDI. • Token ring • WAN • Isdn • PPP • Frame relay • DSL • ATM • Cable modems • T1

15. CSMA / DA. • CSMA/CD is a simple system. Everyone on the system listens for quiet, at which time it is OK to transmit. However, if two people talk at the same time, a collision occurs, and neither person can transmit. Everyone else on the system also hears the collision, waits for silence, and then tries to transmit. • Non-deterministic Ethernet uses a first-come first-served MAC protocol that contends for access to the media.

16. Network Architecture Models. Why use models to describe the operation of network devices.

17. Focus of the CCNA

18. Network Models. ISO OSI 7-Layer Model. Data Stream Data Stream Data Stream Segment Logical Address ( IP Address ) Physical Address ( MAC Address ) Digital Transmission Packet Frame Bits

19. OSI Layers

20. Internet Connectivity • TCP/IP Transfer Control Protocol / Internet Protocol • TCP Connection orientated, reliable transfer protocol. • UDP Connectionless, unreliable. • IP Layer-3 logical addressing. • IPv4 32 bit addressing • IPv6 128 bit addressing

21. Ethernet Interfaces. RJ45 and AUI Interfaces. DIX Ethernet II – RJ45 IEEE 802.3 – AUI Transceiver used to convert media types or interfaces.

22. Network Maths. • Three numbering systems are of most interest in networking. • Denary / Decimal ( base 10 ) • 0,1,2,3,4,5,6,7,8,9 • Binary ( base 2 ) • 0,1 • Hexadecimal ( base 16 ) • 0,1,2,3,4,5,6,7,8,9,a.b.c.d.e.f

23. Network Maths. Decimal/ Denary Number system. Binary Number System. Hexadecimal Number System.

24. Network Maths. Hexadecimal digits with decimal and binary equivalents. Each hexadecimal digit can be represented by four binary bits. Hex a3c Binary 101000111100 a 3 c 1010 0011 1100

25. Network Terminology. • Network Types: • LAN Local Area Network • WAN Wide Area Network • MAN Metropolitan Area Network • SAN Storage Area Network

26. Network Terminology. LAN Networking device icons.

27. Network Terminology. Networking Physical Topologies.

28. Network Terminology. Comparison of networking models.

29. Network Terminology. Data Encapsulation.

30. Data Encapsulation Example Application Header + data Application Layer Layer 4: Transport Layer Layer 3: Network Layer Layer 2: Network Layer 010010100100100100111010010001101000… Layer 1: Physical Layer

31. Copper Media. Shielded Twisted-Pair Cable. ScTP (Screened Twisted Pair) Unscreened Twisted Pair Cable.

32. Copper Media. EIA/TIA T568A & T568B Wiring. Looking into an Ethernet socket.

33. Copper Media. Cancellation Effect. Reduces effect of external interference, and minimises cross-talk generated internally.

34. Optical Media.

35. Optical Media. • Multi Mode • LED transmitting within the range 850nm to 1310nm • LAN data distance up to 2000m • Single Mode • Laser transmitting within the range 1310nm to 1550nm • LAN data distance up to 3000m

36. Cable Testing. • Cable characteristics. • Attenuation. • Loss of signal amplitude at the receiver. • Cross Talk. • Interference between signal pairs. • Delay. • Time difference between signal transmit and reception . With twisted-pair cables the delay on each pair will be different due to differences in length, • Laser noise • Noise at the transmitter or receiver of an optical signal.

37. Wire map Insertion loss Near-end crosstalk (NEXT) Power sum near-end crosstalk (PSNEXT) Equal-level far-end crosstalk (ELFEXT) Power sum equal-level far-end crosstalk (PSELFEXT) Return loss Propagation delay Cable length Delay skew Cable Testing. TIA/EIA-568-B standard specifies 10 tests

38. LAN & WAN. LAN Physical Layer Implementation. IEEE 10BASE2 802.3a 10BASE5 802.3 10BASE-T 802.3i 100BASE-TX 802.3x 100BASE-FX 802.3u 1000BASE-T 802.3ab 1000BASE-SX 802.3z 1000BASE-LX 802.3z 10GBASE-SR 802.3ae 10GBASE-LX4 802.3ae 10GBASE-LR / -XR 802.3ae 10GBASE-SW / -LW / -EW 802.3ae

39. LAN & WAN. • Repeaters • Operate at OSI layer-1, regenerate and retime the electrical signal. • Hubs. • Multi port repeaters, operate at OSI layer-1. • Bridges. • Operate at OSI layer-2, inspects layer-2 MAC destination address of frame. • Switches. • Multi port bridges, has a switching table (CAM table) to determine output port, forwards frame out of output port. • Routers. • Operate at OSI layer-3, inspects IP address, consults routing table, switches frame to interface.

40. LAN & WAN. • Repeaters and hubs. • Extends collision domains. • Broadcast / multicast frames forwarded. • Bridges and switches. • Limit collision domains. • Forward broadcast / multicast frames • Routers. • Break collision domains. • Control forwarding of broadcast / multicast frames.

41. LAN & WAN.

42. LAN & WAN. LAN Switch Advantages.

43. LAN & WAN. WAN Serial connectors. ISDN Connectors. U to U , ST to ST

44. Objectives

45. Introduction to Ethernet

46. IEEE Ethernet Naming Rules

47. Ethernet and the OSI Model

48. Ethernet and the OSI Model

49. Ethernet and the OSI Model

50. Ethernet and the OSI Model