1. Why Use a Computer Network?
Sharing information (or data)
Sharing hardware and software
Centralizing administration and support

2. The sneakernet

3. Sharing Hardware and Software

4. Network Configuration Overview
Servers—Computers that provide shared resources to network users.
Clients—Computers that access shared network resources provided by a server.
Media—The wires that make the physical connections.
Shared data—Files provided to clients by servers across the network.

5. Network Topology A network's topology affects its capabilities
Type of equipment the network needs.
Capabilities of the equipment.
Growth of the network.
Way the network is managed.

6. Standard Topologies Bus Star Ring Mesh
All network designs stem from four basic topologies:
Bus
Star
Ring
Mesh

7. Bus topology network

8. Communication on the Bus
Sending the signal
Signal bounce
Terminator

9. The following are affect the network performance
Number of computer in the network
Hardware capabilities of computers on the network
Total number of queued commands waiting to be executed
Types of applications (client-server or file system sharing, for example) being run on the network
Types of cable used on the network
Distances between computers on the network

10. Terminator

11. Star

12. Ring

13. Token Passing
One method of transmitting data around a ring is called token passing

14. Mesh

15. Variations on the Standard Topologies
Many working topologies are hybrid combinations of the bus, star, ring, and mesh topologies

16. Star Bus

17. Star Ring

19. Network interface card
Protocols – Ethernet, Token Ring, or FDDI
Types of media – Twisted-pair, coaxial, wireless, or fiber-optic
Type of system bus – PCI or ISA

20. Situations that require NIC installation include the following
Installation of a NIC on a PC that does not already have one
Replacement of a malfunctioning or damaged NIC
Upgrade from a 10-Mbps NIC to a 10/100/1000-Mbps NIC
Change to a different type of NIC, such as wireless
Installation of a secondary, or backup, NIC for network security reasons

22. The following are some of the factors that determine throughput:
Internetworking devices
Type of data being transferred
Network topology
Number of users on the network
User computer
Server computer
Power conditions
Using the formula transfer time = size of file / bandwidth (T=S/BW)

23. Network Cabling Coaxial cable
Twisted-pair (unshielded and shielded) cable
Fiber-optic cable
Wireless

24. Cable specification

25. Coaxial Cable

26. There are two types of coaxial cable:
Thin (thinnet) cable
Thick (thicknet) cable
The thicker the copper core, the farther the cable can carry signals

27. Coaxial-Cable Connection Hardware

29. Twisted-Pair Cable Types of twisted-pair cable
Unshielded Twisted-Pair (UTP) Cable
Shielded Twisted-Pair (STP) Cable

30. RJ-45 connector

31. UTP cabling wire colors are two types

33. UTP cable

34. Straight through

35. Use straight-through cables for the following connections:
Switch to router
Switch to PC or server
Hub to PC or server

36. Straight through

37. Straight through

38. Cross over

39. Use crossover cables for the following connections
Switch to switch
Switch to hub
Hub to hub
Router to router
PC to PC
Router to PC

40. Cross over

41. Cross over

42. Roll over

43. Roll over

44. Roll over

46. Fiber-optic cable

47. Wireless

49. Wireless

50. Single wire punch

51. PART TWO

52. Types of Networking
Peer-to-peer
Server based

53. Peer to peer versus client-server

54. OSI MODELS

55. Networking Models

56. Dividing the network into seven layers provides the following advantages:
It breaks network communication into smaller, more manageable parts.
It standardizes network components to allow multiple vendor development and support.
It allows different types of network hardware and software to communicate with each other.
It prevents changes in one layer from affecting other layers.
It divides network communication into smaller parts to make learning it easier to understand.

62. Peer-to-peer communications

64. Cabling LAN Materials used in networking LAN REPEATERS HUBS BRIDGE
SWITCH
ROUTERS

65. REPEATERS Is two port (for signal i/o)
It simply give strength for signal

66. HUBS Hubs are actually multiport repeaters
Passive: used only to share the physical media
(It does not boost or clean the signal )
Active: it needs power to amplify
Intelligent: microprocessor chips and diagnostic capabilities

67. Hub

68. Five segments of network media Four repeaters or hubs
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 with no hosts
One large collision domain

69. BRIDGE Used to segment a large LAN to smaller.
decreases the amount of traffic on a single LAN
bridges operate at the data link layer of the OSI model
The function of the bridge is to make intelligent decisions about whether or not to pass signals on to the next segment of a network.

70. BRIDGE
When a bridge receives a frame on the network, the destination MAC address is looked up in the bridge table to determine whether to:-
Filter
Flood
Copy the frame onto another segment

71. Filter
If the destination device is on the same segment as the frame, the bridge will not send the frame onto other segments. This process is known as filtering

72. Flood
If the destination address is unknown to the bridge, the bridge forwards the frame to all segments except the one on which it was received. This process is known as flooding.

73. Copy the frame onto another segment
If the destination device is on a different segment, the bridge forwards the frame to the appropriate segment.

79. SWITCH A switch is sometimes described as a multiport bridge
Switches reduce traffic and increase bandwidth
Switches operate at much higher speeds than bridges and can support new functionality, such as virtual LANs.

84. ROUTERS
Routers are responsible for routing data packets from source to destination within the LAN, and for providing connectivity to the WAN.
The DTE is the endpoint of the user’s device on the WAN link.
The DCE is typically the point where responsibility for delivering data passes into the hands of the service provider.

85. DTE & DCE

89. TCP-IP

90. TCP/IP MODEL

91. TCP/IP MODEL

92. TCP/IP MODEL

93. TCP/IP MODEL

94. TCP/IP MODEL

95. The OSI and TCP/IP models have many similarities:
Both have layers.
Both have application layers, though they include different services.
Both have comparable transport and network layers.
Both use packet-switched instead of circuit-switched technology.
Networking professionals need to know both models.

96. Some differences of the OSI and TCP/IP models:
TCP/IP combines the OSI application, presentation, and session layers into its application layer.
TCP/IP combines the OSI data link and physical layers into its network access layer.
TCP/IP appears simpler because it has fewer layers.
When the TCP/IP transport layer uses UDP it does not provide reliable delivery of packets. The transport layer in the OSI model always does.
The Internet was developed based on the standards of the TCP/IP protocols.
The OSI model is not generally used to build networks. The OSI model is used as a guide to help students understand the communication process.

97. NETWORK ADDRESSING

98. IP Addressing The Hierarchical IP Addressing Scheme
There are three types of IP addressing
Dotted-decimal, as in
Binary, as in
Hexadecimal, as in AC.10.1E.38

99. Network Addressing called the network number
uniquely identifies each network

102. Network Address Range: Class A 00000000 = 0
= 127
Network Address Range: Class B
= 128
= 191
Network Address Range: Class C
= 192
= 223
Network Address Ranges: Classes D and E
Class D (224–239)
Class E (240–255

103. Class A network.node.node.node
In a Class A network address, the first byte is assigned to the network address, and the three remaining bytes are used for the node addresses:
All host bits off is the network address:
All host bits on is the broadcast address:

104. Private IP Addresses (they’re not routable through the Internet)
Reserved IP Address Space
Address Class Reserved address space
Class A through
Class B through
Class C through

108. Introduction to Network Address Translation (NAT)
to translate your private inside addresses to a global outside address by using NAT
There are different flavors of NAT
Static NAT
Dynamic NAT
Overloading

109. Classless Inter-Domain Routing (CIDR)
It’s basically the method that ISPs (Internet Service Providers) use to allocate an amount of addresses to a company, a home—a customer
When you receive a block of addresses from an ISP, what you get will look something like this: /28.(The slash notation (/) means how many bits are turned on (1s))

112. Broadcast Addresses
Layer 2 broadcasts These are sent to all nodes on a LAN.
Broadcasts (layer 3) These are sent to all nodes on the network.
Unicast These are sent to a single destination host.
Multicast These are packets sent from a single source, and transmitted to many devices on different networks

113. Subnetting Basics Reduced network traffic
Optimized network performance
Simplified management
Facilitated spanning of large geographical distances

114. How to Create Subnets Follow these steps:
1.Determine the number of required network IDs:
One for each subnet
One for each wide area network connection
2.Determine the number of required host IDs per subnet:
One for each TCP/IP host
One for each router interface
3.Based on the above requirements, create the following:
One subnet mask for your entire network
A unique subnet ID for each physical segment
A range of host IDs for each subnet

115. Subnetting

116. Subnetting a Class C Address
Answer five simple questions:
How many subnets does the chosen subnet mask produce?
How many valid hosts per subnet are available?
What are the valid subnets?
What’s the broadcast address of each subnet?
What are the valid hosts in each subnet?

117. Subnetting a Class C Address

118. How many subnets. 2^x = number of subnets
How many subnets? 2^x = number of subnets. x is the number of masked bits, or the 1s
How many hosts per subnet? 2^y – 2 = number of hosts per subnet. y is the number of unmasked bits, or the 0s. For example, in , the number of zeros gives us 26 – 2 hosts. In this example, there are 62 hosts per subnet
What are the valid subnets? 256 – subnet mask = block size, or increment number. An example would be 256 – 192 = 64. The block size of a 192 mask is always 64. Start counting at zero in blocks of 64 until you reach the subnet mask value and these are your subnets. 0, 64, 128, 192.
What’s the broadcast address for each subnet? the broadcast address is always the number right before the next subnet.
What are the valid hosts? Valid hosts are the numbers between the subnets, omitting all the 0s and all 1s.

119. Practice Example #1: 255.255.255.192 (/26)
Let’s use the Class C subnet mask from the preceding example, , to see how much simpler this method is than writing out the binary numbers. We’re going to subnet the network address and subnet mask

120. How many subnets? Since 192 is 2 bits on (11000000), the answer would be 22.
How many hosts per subnet? We have 6 host bits off ( ), so the equation would be 26 – 2 = 62 hosts.
What are the valid subnets? 256 – 192 = 64. Remember, we start at zero and count in our
block size, so our subnets are 0, 64, 128, and 192.

122. Practice Example #2: (/27) This time, we’ll subnet the network address and subnet mask

123. How many subnets? 224 is 11100000, so our equation would be 23 = 8.
How many hosts? 25 – 2 = 30.
What are the valid subnets? 256 – 224 = 32. We just start at zero and count to the subnet
mask value in blocks (increments) of 32: 0, 32, 64, 96, 128, 160, 192, 224.