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. WAN LAN Isdn PPP
Frame relay
DSL
ATM
Cable modems T1
LAN
Ethernet / IEEE
FDDI.
Token ring

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. Layer 7 Layer 7 Application.
Data Stream
Layer 7
Application.
Layer 6
Presentation
Layer 5
Session
Layer 4
Transport
Layer 3
Network
Layer 2
Data Link
Layer 1
Physical
Layer 7
Application.
Layer 6
Presentation
Layer 5
Session
Layer 4
Transport
Layer 3
Network
Layer 2
Data Link
Layer 1
Physical
Data Stream
Data Stream
Segment
Logical Address
( IP Address )
Physical Address
( MAC Address )
Digital Transmission
Packet
Frame
Bits

19. OSI Layers 7 Application 6 Presentation 5 Session 4 Transport
Network Processes to Applications I.e. , FTP
6 Presentation
Data format & data structures, data syntax & transfer, readability
5 Session
Interhost Communication- establishes, manages, & terminates sessions between applications
4 Transport
End-to-end Connections, establish, maintain, terminate Virtual circuits, fault detection & recovery
3 Network
Network Address &
best path determination, error notification
2 Data Link
Direct Link Control, Access to Media
1 Physical
Binary Transmission- wires, connectors, voltages, data rates

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 – 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.
103
102
101
100
1000 10 1
Binary Number System. 27 26 25 24 23 22 21 20
128 64 32 16 8 4 2 1
Hexadecimal Number System.
163
162
161
160
4096
256 16 1

24. Network Maths. Hexadecimal digits with decimal and binary equivalents.
0000 1
0001 2
0010 3
0011 4
0100 5
0101 6
0110 7
0111 8
1000 9
1001 A 10
1010 B 11
1011 C 12
1100 D 13
1101 E 14
1110 F 15
1111
Hexadecimal digits with decimal and binary equivalents.
Each hexadecimal digit
can be represented by four
binary bits.
Hex a3c
Binary
a c

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 …
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.
Run 3.2.6

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. Cable Testing. Wire map Insertion loss Near-end crosstalk (NEXT)
TIA/EIA-568-B standard specifies 10 tests
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

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

39. LAN & WAN. Repeaters Hubs. Bridges. Switches. Routers.
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. Bridges and switches. Routers.
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
The success of Ethernet is due to the following factors:
Simplicity and ease of maintenance
Ability to incorporate new technologies
Reliability
Low cost of installation and upgrade
The introduction of Gigabit Ethernet has extended the original LAN technology to distances that make Ethernet a MAN and WAN standard.

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

51. Ethernet and the OSI Model

52. Naming
An address system is required to uniquely identify computers and interfaces to allow for local delivery of frames on the Ethernet

53. Naming
Ethernet uses MAC addresses that are 48 bits in length and expressed as 12 hexadecimal digits. The first six hexadecimal digits, which are administered by the IEEE, identify the manufacturer or vendor. This portion of the MAC address is known as the Organizational Unique Identifier (OUI). The remaining six hexadecimal digits represent the interface serial number or another value administered by the manufacturer. MAC addresses are sometimes referred to as burned-in MAC addresses (BIAs) because they are burned into ROM and are copied into RAM when the NIC initializes.

54. Media Access Control (MAC)
MAC refers to protocols that determine which computer in a shared-media environment, or collision domain, is allowed to transmit data. MAC and LLC comprise the IEEE version of the OSI Layer 2. MAC and LLC are sublayers of Layer 2. The two broad categories of MAC are deterministic and non-deterministic.
Examples of deterministic protocols include Token Ring and FDDI. In a Token Ring network, hosts are arranged in a ring and a special data token travels around the ring to each host in sequence. When a host wants to transmit, it seizes the token, transmits the data for a limited time, and then forwards the token to the next host in the ring. Token Ring is a collisionless environment since only one host can transmit at a time.
Non-deterministic MAC protocols use a first-come, first-served approach. CSMA/CD is a simple system. The NIC listens for the absence of a signal on the media and begins to transmit. If two nodes transmit at the same time a collision occurs and none of the nodes are able to transmit.
Three common Layer 2 technologies are Token Ring, FDDI, and Ethernet. All three specify Layer 2 issues, LLC, naming, framing, and MAC, as well as Layer 1 signaling components and media issues. The specific technologies
Ethernet – uses a logical bus topology to control information flow on a linear bus and a physical star or extended star topology for the cables
Token Ring – uses a logical ring topology to control information flow and a physical star topology
FDDI – uses a logical ring topology to control information flow and a physical dual-ring topology
Examples of deterministic protocols include Token Ring and FDDI. In a Token Ring network, hosts are arranged in a ring and a special data token travels around the ring to each host in sequence. When a host wants to transmit, it seizes the token, transmits the data for a limited time, and then forwards the token to the next host in the ring.
Token Ring is a collisionless environment since only one host can transmit at a time.

55. MAC Rules and Collision Detection/Backoff
Ethernet is a shared-media broadcast technology. The access method CSMA/CD used in Ethernet performs
three functions
Transmitting and receiving data packets
Decoding data packets and checking them for valid addresses before passing them to the upper layers of the OSI model
Detecting errors within data packets or on the network
Ethernet is a shared-media broadcast technology. The access method CSMA/CD used in Ethernet performs three functions:
In the CSMA/CD access method, networking devices with data to transmit work in a listen-before-transmit mode. This means when a node wants to send data, it must first check to see whether the networking media is busy. If the node determines the network is busy, the node will wait a random amount of time before retrying. If the node determines the networking media is not busy, the node will begin transmitting and listening. The node listens to ensure no other stations are transmitting at the same time. After completing data transmission the device will return to listening mode.

56. MAC Rules and Collision Detection/Backoff
Networking devices detect a collision has occurred when the amplitude of the signal on the networking media increases. When a collision occurs, each node that is transmitting will continue to transmit for a short time to ensure that all nodes detect the collision. When all nodes have detected the collision, the backoff algorithm is invoked and transmission stops. The nodes stop transmitting for a random period of time, determined by the backoff algorithm. When the delay periods expire, each node can attempt to access the networking media. The devices that were involved in the collision do not have transmission priority.

57. Types of Ethernet

58. 1000BASE-FX Pinout

59. Bridges

60. Ethernet Switching.
Switching, multi-port bridging.

61. Full Duplex

62. Network Latency 5-4-3-2-1 rule ( Also known as the 5-4-3 rule.
The rule requires that the following guidelines should not be exceeded:
Five segments of network media
Four repeaters or hubs
Three host segments of the network
Two link sections (no hosts)
One large collision domain
 The rule also provides guidelines to keep round-trip delay time in a shared network within acceptable limits.

63. Switch Modes

64. Switch Port Modes Store and Forward Cut-Through
A switch receives the entire frame before sending it out the destination port.
Cut-Through
A switch starts to transfer the frame as soon as the destination MAC address is received.
Fragment-Free, the first 64 bytes are checked before the frame is forwarded.

65. Spanning-Tree Operation
Redundant routes provide a means of recovering from failures.
Redundant routes lead to switching loops
Switching loops are very undesirable.
Spanning Tree Protocol (STP) is used to prevent loops.

66. STP States

67. Types of Networks

68. Layer 1 Devices Extend Collision Domains

69. Collision Domains.
Collision Domains are broken by OSI layer-2 devices ( Bridges & Switches ), and by Layer –3 devices (Routers).

70. Broadcast Domain.
A bridged or switched network breaks collision domains, but is one broadcast domain.

71. Broadcast Domain Segmentation
Broadcast Domains are broken by OSI layer-3 devices (Routers).

72. TCP/IP
TCP/IP Applications.

73. TCP/IP Transport Layer Protocols. TCP and UDP
Segments upper-layer application data
Sends segments from one end device to another end device
TCP only
Establishing end-to-end operations
Flow control provided by sliding windows
Reliability provided by sequence numbers and Acknowledgements.

74. TCP/IP
Network Access layer.
Network layer Protocols.

75. Application port numbers.
TCP/IP
Application port numbers.
Numbers 255 and below are for public applications.
Numbers from 256 to 1023 are assigned to companies for marketable applications.
Numbers 1024 and above are unregulated.

76. TCP Connection orientated.
TCP/IP
TCP Connection orientated.
For a connection to be established, the two end stations must synchronize on each other's initial TCP sequence numbers (ISNs).
A ->B SYN -- My sequence number is X. A <- B ACK --Your sequence number is X+1. A <- B SYN -- My sequence number is Y. A ->B ACK -- Your sequence number is Y+1.

77. TCP Connection orientated & Reliable.
TCP/IP
TCP Connection orientated & Reliable.
To govern the flow of data between devices, TCP uses a peer-to-peer flow control mechanism.
Window size refers to the number of packets that are transmitted before receiving an acknowledgment. After a host transmits the number of packets equal to the window-size, it must receive an acknowledgment before any more packets can be sent.

78. TCP/IP

79. TCP/IP

80. TCP/IP
IPv4 Addresses.

81. TCP/IP IPv4 Address structure. 32 bit binary number.
Divided into four 8 bit octets.
Each octet expressed as a denary number.

82. TCP/IP 32 Bit Binary to Dotted Quad Format. 2

83. TCP/IP Address Classes. Class A B C D First Octet 0XXXXXXX. 10XXXXXX.
Network
Address Range
1.  126.
128.  191.
192.  223.
224.  239.
Class A B C D
First Octet
0XXXXXXX.
10XXXXXX.
110XXXXX,
1110XXXX.

84. TCP/IP Address Examples. 203.10.1.0 Class C 47.0.0.0 Class A
Class B

85. TCP/IP Class A NETWORK . HOST . HOST . HOST
IP Address = NETWORK PORTION + HOST PORTION.
Class A NETWORK . HOST . HOST . HOST
Class B NETWORK . NETWORK . HOST . HOST
Class C NETWORK . NETWORK . NETWORK . HOST

86. TCP/IP
Special Cases.
Ethernet local loop-back address on Ethernet NICs.   
Private Addresses ( RFC 1918 ) Not forwarded in the internet.

87. TCP/IP Simple DHCP operation. Dynamic IP allocation.
DHCP uses UDP ports 67, and 68. (BOOTP ports)

88. ARP Address Resolution Protocol.
TCP/IP
ARP Address Resolution Protocol.
What is the MAC address to use when sending data to a know local IP address.