1. Welcome to network+

2. Cisco ( CCNA, CCNP, CCIE, … )
Comptia (Network+, Server+, Linux+, Security+, e-Biz+, A+ )
Microsoft (MCP, MCSE, MCSD,MCITP, ….)
Redhat Red Hat Certified Technician (RHCT).
SUN Solaris

5. A requisite for CCNA Course
Passing the Network+ Exam and get the certification
Representing a solid background of networking knowledge regarding Network+ standard course

8. Basic Networking Fundamentals

9. What is a Computer Network ?=
What is a Computer Network ?
Two or more computers connected together, having the ability to use shared resources on each other.
Two computers that are connected with a Network Cable through their network cards are an example of a simple network.

10. Something to share ( Data )
Physical Pathway ( Transmission medium )
Interfaces for communication ( Network Interface )
Rules of Communication ( Protocols )

11. What are some of the different types of the network?
In a clinent/server network each host will act Specifically as a Server (the provider of resources) or a Client (the receiver of resources)

12. What are some of the different types of the network?
Peer to peer
In a peer to peer network every host will act as a client AND a server

13. What are some of the different types of the network?
LAN –Local Area Network
Typically refers to a network contained whitin a building

14. MAN – Metropolitan Area Network
A network spread between non-contiguous
Buildings within a single metropolitan area.

15. WAN –Wide Area Network
A network spread over a wide area ,typically covering multiple cities and countries.

16. Network Types ( 2 ) Network Topologies : 1 – Bus 2 – Star 3 – Ring
4 – Mesh (Full mesh Vs. Partial mesh)
5 -Tree
6 - Hybrid

17. Bus Topology

18. Star Topology

19. Ring Topology

20. Mesh Topology

21. Tree Topology

22. Hybrid Topology

23. Network Types Transmission Methods : Circuit switching
Dedicated path is created between two nodes
Packet switching
Message is broken into small packets

24. Circuit Switching
A circuit is established, an end-to-end connection must exist to transfer data
The actual data transfer
After data transmitted, connection is terminated

25. Packet Switching Message is broken into small packets.
Allows interactive exchanges because of small packets.
Uses messages that are all the same length (called packets)

26. Network Terminology (1)
Client
Server
Host
Workstation
Peer

27. Network Terminology (2)
Backbone
A part of a network that all segments and servers connect. (Gigabit Ethernet, FDDI, Thicknet)
Segment
Any short section of the network that is connected to the backbone

28. Network Terminology (3)
Half-duplex
A bi-directional communication but only one direction at a time, such as walkie-talkie
Full-duplex
Allows communications in both directions simultaneously.

29. Network Terminology (4)
Broadband Vs. Baseband
With baseband the whole bandwidth of the cable is used for each signal (channel), but in broadband the bandwidth is divided into descrete bands

30. PHYSICAL MEDIA

31. Physical Media )

32. Copper
Coaxial Cable - Thick or Thin
Unshielded Twisted Pair
Optical Fiber
Multimode
Singlemode
Wireless
Short Range
Medium Range (Line of Sight)
Satellite

33. Copper Media: Coaxial Cable
Coaxial cable is a copper-cored cable surrounded by a heavy shielding and is used to connect computers in a network.
Outer conductor shields the inner conductor from picking up stray signal from the air.
High bandwidth but lossy channel.
Repeater is used to regenerate the weakened signals.
Category
Impedance
Use
RG-59
75 W
Cable TV
RG-58
50 W
Thin Ethernet
RG-11
Thick Ethernet

34. Copper Media: Twisted Pair
Twisted-pair is a type of cabling that is used for telephone communications and most modern Ethernet networks.
A pair of wires forms a circuit that can transmit data. The pairs are twisted to provide protection against crosstalk, the noise generated by adjacent pairs.
There are two basic types, shielded twisted-pair (STP) and unshielded twisted-pair (UTP).

35. Shielded Twisted Pair (STP)

36. Unshielded Twisted Pair (UTP)

37. Unshielded Twisted Pair (UTP)
Consists of 4 pairs (8 wires) of insulated copper wires typically about 1 mm thick.
The wires are twisted together in a helical form.
Twisting reduces the interference between pairs of wires.
High bandwidth and High attenuation channel.
Flexible and cheap cable.
Category rating based on number of twists per inch and the material used
CAT 3, CAT 4, CAT 5, Enhanced CAT 5 and CAT 6.

38. EIA/TIA 568A vs 568 B

39. Fiber Media
Optical fibers use light to send information through the optical medium.
It uses the principal of total internal reflection.
Modulated light transmissions are used to transmit the signal.

40. Total Internal Reflection

41. Fiber Media
Light travels through the optical media by the way of total internal reflection.
Modulation scheme used is intensity modulation.
Two types of Fiber media :
Multimode
Singlemode
Multimode Fiber can support less bandwidth than Singlemode Fiber.
Singlemode Fiber has a very small core and carry only one beam of light.

42. Single and Multimode Fiber
Single-mode fiber
Carries light pulses along single path
Uses Laser Light Source
Multimode fiber
Many pulses of light generated by LED travel at different angles

43. Network Terminology (5)
Fiber-Optic Cable
Contains one or several glass fibers at its core
Surrounding the fibers is a layer called cladding

44. Fiber Optic Cable
FO Cable may have 1 to over 1000 fibers

45. Fiber optic connectors
ST (Straight Tip) Connector

46. Fiber optic connectors.
SC Connector

47. Fiber optic connectors
MT-RJ LC

48. Wireless Media
Very useful in difficult terrain where cable laying is not possible.
Provides mobility to communication nodes.
Right of way and cable laying costs can be reduced.
Susceptible to rain, atmospheric variations and Objects in transmission path.

49. Installation type
Infrastructor

50. Installation type
Ad-hoc

51. Unidirectional antennas

52. Type of Transmission
Unicast
Multicast
Broadcast

53. Type of Transmission

54. Broadcast Domain
A group of devices receiving broadcast frames initiating from any device within the group
Routers do not forward broadcast frames

55. Collision
The effect of two nodes sending transmissions simultaneously in Ethernet. When they meet on the physical media, the frames from each node collide and are damaged.
Exam Watch Make sure you understand the mechanics of Ethernet: CSMA/CD. No device has priority over another device. If two devices transmit simultaneously, a collision occurs. When this happens, a jam signal is generated and the devices try to retransmit after waiting a random period.

56. Collision Domain
The network area in Ethernet over which frames that have collided will be detected.
Collisions are propagated by hubs and repeaters
Collisions are Not propagated by switches, routers, or bridges
If two or more machines simultaneously sense the wire and see no frame, and each places its frame on the wire, a collision will occur. In this situation, the voltage levels on a copper wire or the light frequencies on a piece of fiber get messed up. For example, if two NICs attempt to put the same voltage on an electrical piece of wire, the voltage level will be different than if only one device does so. Basically, the two original frames become unintelligible (or undecipherable). The NICs, when they place a frame on the wire, examine the status of the wire to ensure that a collision does not occur: this is the collision detection mechanism of CSMA/CD.
If the NICs see a collision for their transmitted frames, they have to resend the frames. In this instance, each NIC that was transmitting a frame when a collision occurred creates a special signal, called a jam signal, on the wire, waits a small random time period, and senses the wire again. If no frame is currently on the wire, the NIC will then retransmit its original frame. The time period that the NIC waits is measured in microseconds, a delay that can’t be detected by a human. Likewise, the time period the NICs wait is random to help ensure a collision won’t occur again when these NICs retransmit their frames.
The more devices you place on a segment, the more likely you are to experience collisions. If you put too many devices on the segment, too many collisions will occur, seriously affecting your throughput. Therefore, you need to monitor the number of collisions on each of your network segments. The more collisions you experience, the less throughput you’ll get. Normally, if your collisions are less than one percent of your total traffic, you are okay. This is not to say that collisions are bad—they are just one part of how Ethernet functions.

57. Networking device

58. Objectives
Explain the uses, advantages, and disadvantages of repeaters
Explain the uses, advantages, and disadvantages of hubs
Define wireless access points
Define network segmentation
Explain network segmentation using bridges

59. Objectives (continued)
Explain network segmentation using switches
Explain network segmentation using routers
Brouters is a term

60. Repeaters Length of cable used influence the quality of communication
Repeaters repeat signals
Repeaters only work with the physical signal
Cannot reformat, resize, or manipulate the data
Physical layer (layer 1) device

61. Repeaters (continued)

62. Repeaters (continued)

63. Hubs Generic connection device
Physical layer
Connect several networking cables together
Active hubs
Multiport repeaters
Passive hubs
Hubs and topology

64. Hubs (continued)

65. Advantages And Disadvantages Of Repeaters And Hubs
Advantages of using repeaters
Extend network physical distance
Do not seriously affect network performance
Disadvantages of using repeaters
Cannot connect different network architectures
Token Ring and Ethernet
Cannot reduce network traffic

66. Advantages And Disadvantages Of Repeaters And Hubs (continued)
Disadvantages of using repeaters
Do not segment the network
Repeat everything without discrimination
Number of repeaters must be limited
Repeaters are part of a collision domain

67. Hubs & Collision Domains
More end stations means more collisions.
CSMA/CD is used.
Tk-10-7

68. Wireless Access Points
Wireless local area networks (WLANs)
Wireless access points provide cell-based areas
Contains radio transceiver
Function like a hub
Bandwidth is shared
May also function as a wireless repeater
Wireless clients

69. Wireless Access Points (continued)

70. Network Segmentation
Problems occur with too many nodes on the same network segment or collision domain

71. Network Segmentation (continued)

72. Bridges Operate at the Data Link layer Forward or drop frames
Cannot filter broadcasts
MAC to segment # table

73. Bridges (continued)

74. Advantages And Disadvantages Of Bridges
Advantages of using a bridge
Reduce network traffic with minor segmentation
Creates separate collision domains
Reduce collisions

75. Advantages And Disadvantages Of Bridges (continued)
Disadvantages of using bridges
Slower due to filtering
Do not filter broadcasts
More expensive

76. Switches Operate at the Data Link layer Increase network performance
Virtual circuits between source and destination
Micro segmentation

77. Devices On Layer 2 (Switches & Bridges)
Data-Link OR 1 2 3 4 1 2
Each segment has its own collision domain.
All segments are in the same broadcast domain.

78. Switches Switch Each segment is its own collision domain.
Memory
Each segment is its own collision domain.
Broadcasts are forwarded to all segments.
TK16-15

79. MAC Address Table Initial MAC address table is empty. Slide 1 of 3
Emphasize: The 1900en max MAC address table size is Once the table is full, it will flood all new addresses until existing entries age out.
The command to change the MAC address table aging time is, as follows:
wg_sw_a(config)#mac-address-table aging-time ?
< > Aging time value
The default is 300 sec.
The MAC address table is also referred to as the CAM table (Content Address Memory) on some switches.
Initial MAC address table is empty.

80. Learning Addresses Station A sends a frame to station C.
Slide 2 of 3
Station A sends a frame to station C.
Switch caches the MAC address of station A to port E0 by learning the source address of data frames.
The frame from station A to station C is flooded out to all ports except port E0 (unknown unicasts are flooded).

81. Learning Addresses (Cont.)
Slide 3 of 3
Emphasize: Once C replies, the switch will also cache station C’s MAC address to port E2, as shown in the next slide.
Station D sends a frame to station C.
Switch caches the MAC address of station D to port E3 by learning the source address of data frames.
The frame from station D to station C is flooded out to all ports except port E3 (unknown unicasts are flooded).

82. Filtering Frames Station A sends a frame to station C.
Destination is known; frame is not flooded.

83. Broadcast and Multicast Frames
Station D sends a broadcast or multicast frame.
Broadcast and multicast frames are flooded to all ports other than the originating port.

84. Forward/Filter Decision
When a frame arrives at a switch interface, the destination hardware address is compared to the forward/ filter MAC database.
If the destination hardware address is known and listed in the database, the frame is sent out only the correct exit interface
If the destination hardware address is not listed in the MAC database, then the frame is flooded out all active interfaces except the interface the frame was received on.
If a host or server sends a broadcast on the LAN, the switch will flood the frame out all active ports except the source port.

85. Switches (continued) Advantages of switches
Increase available network bandwidth
Reduced workload, computers only receive packets intended for them specifically
Increase network performance
Smaller collision domains

86. Switches (continued) Disadvantages of switches
More expensive than hubs and bridges
Does not filter broadcast traffic

87. Method of Switching - Cut Through Mode
Much faster
Cannot detect corrupt packets
Can propagate the corrupt packets to the network
Best suited to small workgroups

88. Method of Switching - Store and Forward Mode
Read the whole packet before transmit
Slower than the cut-through mode
More accurate since corrupt packets can be detected using the FCS
More suit to large LAN since they will not propagate error packets
Facilitate data transfer between segments of different speed DB
100Mbps
10Mbps

89. Using Switches to Create VLANs
Switches can logically group together some ports to form a virtual local area network (VLAN)
SW1
VLAN1
VLAN2
Hub
SW2
Hub
Switches can be configured to communicate only within the devices in the group
SW3
Hub

90. Switches (continued)

91. Routers Provide filtering and network traffic control
Used on LANs and WANs
Connect multiple segments and networks
Multiple routers create an “internetwork”
Operate at the Network layer

92. Routers (continued) Create a table to determine how to forward packets
Filtering and traffic control base on logical addresses

93. Physical Versus Logical Addresses
MAC addresses
Data Link layer application
Used by switches, bridges, and routers
Used for directly connected devices
Logical addresses
Network and transport protocols dictate the format of the logical network layer address
TCP/IP, IPX/SPX
IP addresses are assigned manually or by software

94. Physical Versus Logical Addresses (continued)

95. Advantages And Disadvantages Of Routers
Can connect networks of different architecture
Token Ring to Ethernet
Choose best path through or to a network
Create smaller collision domains
Create smaller broadcast domains

96. Advantages And Disadvantages Of Routers (continued)
Only work with routable protocols
More expensive than hubs, bridges, and switches
Routing table updates consume bandwidth
Increase latency due to a greater degree of packet filtering and/or analyzing

97. Advantages And Disadvantages Of Routers (continued)

98. Static and Dynamic Routers

99. Layer-3 Switches Why Layer-3 switches?
Layer-3 switches operate in both layer 2 (data link layer) and 3 (network layer)
Can perform both MAC switching and IP routing
A combination of switch and router but much faster and easier to configure than router
Why Layer-3 switches?
Traffic of LAN is no longer local
Speed of LAN is much faster
Need a much faster router, however, very expensive

100. Summary
Repeaters are the least expensive way to expand a network, but they are limited to connecting two segments
Bridges function similar to repeaters, but can understand the node addresses
Switches can be considered as multiport bridges, can divide a network into some logical channels
Routers interconnect networks and provide filtering functions. They can determine the best route

101. Remote Access Devices
1. Modems

102. Cannot send digital signal directly to telephone line
Sending end: MODulate the computer’s digital signal into analog signal and transmits
Receiving end: DEModulate the analog signal back into digital form

103. ADSL ADSL stands for Asymmetric Digital Subscriber Line
Particularly suitable for high speed multimedia communications, general Internet applications
Asymmetric - downstream 1.5 to 6.1Mbps
upstream 16 to 640kbps
Digital - mainly for transmitting digital data
still require modulation and demodulation
Subscriber line - make use of the analog connection between household and COB

104. ADSL Illustration 2 to 3 miles subscriber line Telephone Company
Splitter
local loop
low speed
data
high speed

105. Why Asymmetric?
In general Internet applications, downstream often requires a higher data rate than upstream
Downstream - file download, video playback
Upstream - click a link, send a form
Reducing the resource for upstream can provide more resource for downstream

106. ADSL exploits the unused analogue bandwidth available in the wires
ADSL works by using a frequency splitter device to split a traditional voice telephone line into two frequencies
PSTN
Downstream
Upstream

107. Architecture of ADSL Services
Network Terminology (5)
DSL
Voice Switch
ISP
Central Office
Subscriber premises