41205950 networking and servers

8/4/2019 41205950 Networking and Servers

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SANDEEP,MITHILESH,SYEDUL,RABIKANT

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UNIT 1

Myicon.ico

1. INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.1. Definition of Computer Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.2. Components of Data communication . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21.3. Types of computer networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3.1. Local Area Networks (LANs) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.3.2. Metropolitan Area Network (MAN) . . . . . . . . . . . . . . . . . . . . . . . . 31.3.3. Wide Area Network (WAN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31.3.4. Virtual Private Network (VPN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.3.4.1. Protocols used in VPN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.3.4.2. Internet-based VPNs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.3.4.3. Intranet-based VPNs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51.3.5. Personal Area Network (PAN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2. NETWORKING DEVICES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.1. Repeater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.2. Hub . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

2.1.1. Passive Hubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.1.2. Active Hubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 92.1.3. Intelligent Hubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.3. Bridge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92.4. Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102.5. Router . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112.6. Network Interface Card (Ethernet) . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 122.7. Modem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132.8. VoIP (Voice over Internet Protocol) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2.8.1. Types of VoIP Calls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142.9. Gateway . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 142.10. Connectors RJ 45 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 152.11. Direction of transmission or Data Flow . . . . . . . . . . . . . . . . . . . . . . . . .. 16

2.11.1. Simplex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172.11.2. Half-Duplex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 172.11.3. Full-Duplex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

3. TRANSMISSION MEDIUM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.1. Unguided Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183.2. Guided Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183.3. Twisted-Pair Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.3.1. UTP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193.3.2. STP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

3.4. Coaxial cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193.5. Optical Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 203.6. Comparison of Different mode of Optical Fibers . . . . . . . . . . . . . . . . . . . 21
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4. TRANSMISSION IMPAIRMENT.. 22

4.1. Attenuation... 22

4.2. Distortion.. 224.3. Noise......... 23

4.3.1. Signal-to-Noise Ratio (SNR).... 234.3.2. Throughput.... 23

5. ACCESS POINT............................. 24

5.1 What is Wi-Fi?...............................................................................245.2 Types of Access Points..25

5.2.1 Motorola AP-5131..265.3 AP-5131 Configuration..28

6. SWITCH..35

6.1 TYPE OF SWITCHES ..356.1.1 Two-Layer Switches....356.1.2 Three-Layer Switches..36

6.2 LAN Switch Mechanism and Its Advantages376.3 VLAN.....37

6.3.1 Advantages of VLANs...386.3.2 Types of VLANs.38

7. NETWORK TOPOLOGY..39

7.1 Star Topology 397.2 Ring Topology ...407.3 Bus Topology 41

7.4 Mesh Topology ..41

7.5 Tree Topology ...427.6 Hybrid Topology ...43

8. OSI REFERENCE MODEL44

8.1 Physical Layer ...458.2 Data Link Layer 468.3 Network Layer ..478.4 Transport Layer .478.5 Session Layer 488.6 Presentation Layer 488.7 Application layer ...49

9. FIREWALL.509.1 How Does Firewall Management Work?.......................................509.2 Firewall techniques50

9.2.1 Packet filtering firewall..509.2.2 Stateful firewall..51


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9.2.3 Deep packet inspection firewall..519.2.4 Application-aware firewall..519.2.5 Application proxy firewall..51

9.3 Firewall Rules.529.4 Types of Firewall52

9.4.1 Software firewall.529.4.2 Hardware firewall..53

9.5 The Advantages and Disadvantages of Firewall ..53

9.5.1 Advantages .539.5.2 Disadvantages .54

10. UTM..55

10.1 How UTM secures the network5510.2 Advantages ..56

10.3 Features5610.4UTM Appliance Benefits..............................................................56

11. PROTOCOL...57

11.1 FTP [File Transfer Protocol]57

11.1.1 Anonymous FTP58

11.1.2 How FTP Works?..........................................................58

11.2 TELNET [TErminaL NETwork]..58

11.3 Simple Mail Transfer Protocol (SMTP)......................... .............59

11.4 POP3.61

UNIT -2


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1.WEB SERVER .65

1.1 IIS...651.1.1 Installation...661.1.2 Security Features.70

1.2 Apache Web Server ..701.2.1 Features ..711.2.2 Use...71

2. TEMINAL SERVER72

2.1Terminal Services Architecture .722.1.1 Multi-user kernel ...72

2.1.2 Remote Desktop client72

2.1.3 Terminal Services licensing service...72

2.1.4 Session Directory Services.722.2 Components732.3 Installation & Configuration Terminal Services752.4 How to connect client with Terminal server.82

2.5 Advantages.83

3. WINDOWS SERVER UPDATE SERVICES (WSUS)..84

3.1 Installation .843.1.1 Software Requirements ..

843.1.2 Minimum Hardware Requirements ...843.1.3 Installation Steps85

3.2 Configuring the network873.3 To specify the way this server will obtain updates873.4 Start WSUS87

3.4.1 Configure updates and synchronization.873.4.2 Configure client updates.88

4.BLADE SERVER.89

4.1 Need Of Blade Server.894.2 Features .89

4.2.1 Virtualization.894.2.2 Hot Swapping.904.2.3 Power..904.2.4 Cooling ..904.2.5 Storage904.2.6 LED Indicators...90

4.3 Specification...914.4 Components Of Blade Server.91

4.4.1.Chassis924.4.2 Management server

92

4.4.3 SAN & KVM. 924.5 RAID..93


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4.5.1. Advantages And Disadvantages Of Raid.94

4.6 Configuration.954.6.1. Using the Configuration /Setup Utility program....95

4.6.2. Using the PXE boot agent utility program ....97

4.7Configuring The Gigabit Ethernet Controllers .97

4.8. Blade Server Advantages And Disadvantages.........98

4.8.1. Advantages........98

4.8.2. Disadvantages........99

5. DHCP Server...100

5.1 Installing DHCP Server is very easy in win server 2003.1015.2 Configuring DHCP...110

5.3 Advantages and Disadvantages ...112


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UNIT 1

NETWORKING

1. INTRODUCTION

A network is a set of machines/devices (often referred to as nodes) connected by

communication links to communicate with each other. A node can be a computer,printer, or any other device capable of sending and/or receiving data generated by

other nodes on the network.

Two machines may be directly connected, or can communicate through other

machines

Some machines are sources and destinations of data.

Some devices do not generate data, but facilitate in the transfer (ex. a router)

Networks are an interconnection of two or more computers such that they can

share resources and information.

These computers can be linked together using a wide variety of Cables, ortelephone, or through satellites.


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1.1 Definition of Computer Network

A computer network is an interconnected collection of autonomous computers.

Two computer are interconnected if they are able to exchange information

Two computers are autonomous if they are capable of operatingindependently, that is, neither is

capable of forcibly starting, stopping,

or controlling the other.

1.2 Components of Data

communication

A data communications system has five

components.

1. Message : The message is the information (data) to be communicated. Popular

form of information includes text, numbers, pictures, audio, and video.

2. Sender : The sender is the device that sends the data message. It can be a

computer, workstation, telephone handset, video camera, and so on.

3. Receiver : The receiver is the device that receives the message. It can be a

computer, workstation, telephone handset, video camera, and so on.

4. Transmission medium : The transmission medium is the physical path by

which a message travels from sender to receiver. Example of Transmission

media include twisted pair wire, coaxial cable, fiber-optic cable, and radio

waves.

5. Protocol : A protocol is a set of rules that govern data communications. It

represents an agreement between the communicating devices. Without a

protocol, two devices may be connected but not communicating, just as a

person speaking French cannot be understood by a person who speaks only

Japanese.

1.3 Types of computer networks

1.3.1 Local Area Networks (LANs) : The computers are geographically close

together (that is, in the same building). It confined to a single building or group of

building, Home, Office Building Or School or University (KIIT). It is Either Wired or


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wireless media. Wireless LANs are the newest evolution in LAN technology.LAN

size is limited to a few kilometers.

1.3.2 Metropolitan Area Network (MAN) :

A metropolitan area network (MAN) is a network with a size between a LANand a WAN. It covers the area inside a town or city. It consists of multiple LANs. It is

larger than local-area networks (LANs) but smaller than wide-area networks (WANs).

It is characterized by very high-speed connections using fiber optical cable or other

digital media.

Example- Telephone company network and cable TV network

1.3.3 Wide Area Network (WAN) : A wide area network (WAN) provides long-

distance transmission of data, image, audio, and video information over large

geographic areas thats may comprise a country, a continent, or even the whole world.

It covers a large Geographical area (Kilometers).It consists of two or more LANs.

1.3.4 Virtual Private Network (VPN) : A Virtual Private Network (VPN) is a

network technology that creates a secure

network connection over a public network

such as the Internet or a private network

owned by a service provider. Large

corporations, educational institutions, and

government agencies use VPN technology toenable remote users to securely connect to a

private network.

A VPN can connect multiple sites over a large distance just like a Wide AreaNetwork (WAN). VPNs are often used to extend intranets worldwide to disseminateinformation and news to a wide user base. Educational institutions use VPNs toconnect campuses that can be distributedacross the country or around the world.

In order to gain access to the privatenetwork, a user must be authenticated using a

unique identification and a password. Anauthentication token is often used to gainaccess to a private network through a personalidentification number (PIN) that a user must enter. The PIN is a unique authenticationcode that changes according to a specific frequency, usually every 30 seconds or so.

1.3.4.1 Protocols used in VPN :

There are a number of VPN protocols in use that secure the transport of datatraffic over a public network infrastructure. Each protocol varies slightly in the waythat data is kept secure.

IP security (IPSec) is used to secure communications over the Internet. IPSec

traffic can use either transport mode or tunneling to encrypt data traffic in a VPN. Thedifference between the two modes is that transport mode encrypts only the message


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within the data packet (also known as the payload) while tunneling encrypts the entiredata packet. IPSec is often referred to as a "security overlay" because of its use as asecurity layer for other protocols.

Secure Sockets Layer (SSL) and Transport Layer Security (TLS) usecryptography to secure communications over the Internet. Both protocols use a

"handshake" method of authentication that involves a negotiation of network parameters between the client and server machines. To successfully initiate aconnection, an authentication process involving certificates is used. Certificates arecryptographic keys that are stored on both the server and client.

Point-To-Point Tunneling Protocol (PPTP) is another tunneling protocol usedto connect a remote client to a private server over the Internet. PPTP is one of themost widely used VPN protocols because of it's straightforward configuration andmaintenance and also because it is included with the Windows operating system.

Layer 2 Tunneling Protocol (L2TP) is a protocol used to tunnel datacommunications traffic between two sites over the Internet. L2TP is often used in

tandem with IPSec (which acts as a security layer) to secure the transfer of L2TP datapackets over the Internet. Unlike PPTP, a VPN implementation using L2TP/IPSecrequires a shared key or the use of certificates.

Typical VPN connections are either Internet-based or intranet-based.

1.3.4.2 Internet-based VPNs :

By using an Internet-based VPN connection, you can avoid long-distance and1-800 telephone charges while taking advantage of the global availability of theInternet.

1.3.4.3 Intranet-based VPNs :

The intranet-based VPN connection takes advantage of IP connectivity on anorganization intranet.


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Advantage:-

1. Cost Saving

2. Improved Scalability

3. Improved Security

4. Better Performance

5. Flexibility and Reliability

6. Greater Access to mobile user

Disadvantage:-

1. Less Bandwidth than Dedicated Line

2. Lack of Security

1.3.5 Personal Area Network (PAN) :

Personal devices of one individual: His/her PC, laptop, cell phone, PDA

To allow devices to communicate and work together.

To permit devices to become smarter: spontaneously, network and work

together.

PANs feasibility is growing with improvement of wireless technology:

Bluetooth enabling devices to communicate automatically and wirelessly

when they are in range.

PANs can keep portable devices synchronized with a desktop PC.

E-clothing products (Jacket) equipped with a battery pack and devices.


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2. NETWORKING DEVICES

Computer network devices also known as communication devices and they

constitute a data communication network. Network components and devices are the

physical entities connected to a network. There are many types of network devices

and increasing daily. The basic network devices are: Computers either a PC or a

Server, Hubs, Switches, Bridges, Routers, Gateways, Network interface cards (NICs),

Wireless access points (WAPs), Printers and Modems. In an Ethernet or WAN

network, the data communication cannot be performed without these devices.

Network devices are components used to connect computers or other electronic

devices together so that they can share files or resources like printers or fax machines.

A full list of Computer networking devices is units that mediate data in a computer

network. Computer networking devices are also called network equipment,

Intermediate Systems (IS) or Interworking Unit (IWU). Units which are the last

receiver or generate data are called hosts or data terminal equipment. These devices

are broken into two classifications.

End User Devices : Include computers, printers, scanners, and other

devices that provide services directly to the user.

Network devices : Include all devices that connect the end-user devices toallow them to communicate.


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End user devices that provide users with a connection to the network are also

called hosts.

These devices allow users to share, create, and obtain information. Host

devices can exist without a network, but without a network, host capabilities are

greatly reduced. Host devices are physically connected to the network media using anetwork interface card (NIC). They use this connection to perform the tasks of

sending e-mails, printing reports, scanning pictures, or accessing databases.

2.1 Repeater

Repeaters are networkingdevices that exist at Layer 1, the

Physical layer, of the OSI reference

model. To understand how a repeater

works, it is important to understand that

as data leaves a source and goes out over

the network, it is transformed into either

electrical or light pulses that pass

along the networking medium.

These pulses are called signals.

When signals leave a transmitting

station, they are clean and easily

recognizable. A network repeater

is a device used to expand the

boundaries of a wired or wireless

(WiFi) local area network (LAN).

Repeaters are relatively simple pieces of equipment consisting of an antenna,

duplexer, receiver and transmitter. The reason that repeaters are needed is because a

radio's power is limited by its antenna size. The purpose of a repeater is to regenerate

incoming electrical, wireless or optical signals that are weaker signals and then

broadcast it. With physical media like Ethernet or Wi-Fi, data transmissions can only

span a limited distance before the quality of the signal degrades. Repeaters attempt topreserve signal integrity and extend the distance over which data can safely travel.


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Repeater is to retime network signals at bit level, allowing them to travel a longer

distance on the medium. The term repeater originally meant a single port in device

and a single port out device. Today multiple-port repeaters also exist. Repeaters are

classified as layer 1 devices in the OSI model because they act only on the bit level

and look at no other information.

2.2 Hub

The central connecting device in a computer network is known as a hub. A

USB hub is a device that expands a single USB port into several so that there are

more ports available to connect devices to a host system. Every computer is directly

connected with the hub. When data packets arrives at hub, it broadcast them to all the

LAN cards in a network and the destined recipient picks them and all other computers

discard the data packets. Hub has five, eight, sixteen and more ports and one port is

known as uplink port. Here are three types of network hubs: Passive Hubs, Active

Hubs and Intelligent Hubs.

2.2.1 Passive Hubs : One of the types of a network hub is the so-called passive hub.

It's a pass-through that does not do anything more than just broadcast signals it

receives through its input port, then sends it out through the output port. It does not do

anything to regenerate or process the signals because it only functions as a connector

of different wires in a topology.

2.2.2 Active Hubs : An active hub works more than just a connector but alsoregenerates the data bits to ensure the signals are strong. Another name for an activehub is a multiport repeater. It provides an active participation in the network asidefrom acting as an interface. It participates in the data communication, such as storingsignals received through the input ports, before forwarding them. It can monitor thedata it is forwarding and sometimes help improve signals before forwarding them toother connections. Such a feature makes troubleshooting of network problems easier.

2.2.3 Intelligent Hubs : An intelligent hub can perform everything that the passivehub and active hub do, and help manage the network resources effectively to ensurethat the performance of the network is highly efficient. An intelligent hub can help introubleshooting by pinpointing the actual location of the problem and help identify theroot cause and resolution. It is very adaptable to different technologies without anyneed to change its configuration. The intelligent hub performs different functions such

as bridging, routing, and switching andnetwork management.

Hubs are considered Layer 1devices because they only regeneratethe signal and repeat it out all their

ports (network connections). Hubsamplify signals and propagate signalsthrough the network. Hubs do notrequire filtering and path determinationor switching.

2.3Bridge


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The bridges used in computer networking are not like your typical bridge. Abridge device filters data traffic at a network boundary. Bridges serve a similarfunction as switches. Bridges reduce the amount of traffic on a LAN by dividing itinto two segments. A bridge works on the principle that each network node has itsown address. A bridge forwards the packets based on the address of the particular

destination node. Bridges operate at the data link layer (Layer 2) of the OSI model,which means the bridge cannot read IP addresses, but only the outermost hardwareaddress of the packet. In our case the bridge can read the Ethernet data which givesthe hardware address of the destination address, not the IP address. The hardwareaddress is also called the MAC (media access control) address. Bridges inspectincoming traffic and decide whether to forward or discard it. To determine thenetwork segment a MAC address belongs to, bridges use one of:

Transparent Bridging - They build a table of addresses (bridging table) as theyreceive packets. If the address is not in the bridging table, the packet isforwarded to all segments other than the one it came from. This type of bridgeis used on Ethernet networks.

Source route bridging - The source computer provides path information insidethe packet. This is used on Token Ring networks.

Bridges can be used to:

Expand the distance of a segment.

Provide for an increased number of computers on the network.

Reduce traffic bottlenecks resulting from an excessive number of attachedcomputers.

2.4 Switch

A network switch orswitching hub is a

computer networking device that connects

network segments. Switch is multi-port device.

A networking switch runs in full-duplex mode,

meaning a machine on the LAN can receive and

transmit data simultaneously. This is muchfaster than a networking hub. In the Open


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Systems Interconnection (OSI) communications model, a switch performs the layer2

or Data-Link-Link function. Some newer switches also perform routing functions

(layer3 or the Network layer functions in OSI) and are sometimes called IP switches.

A network switch is a small hardware device that joins multiple computers together

within one local area network (LAN).

Switch provides similar functions as a hub or a bridge but has more advanced

features that can temporarily connect any two ports together. It contains a switch

matrix or switch fabric that can rapidly connect and disconnect ports. Unlike Hub, a

switch only forward frame from one port to the other port where the destination node

is connected without broadcast to all other ports.

2.5 Router

In an environment consisting of several network segments with differentprotocols and architecture, a bridge may

not be adequate for ensuring fastcommunication among all of thesegments. A complex network needs adevice, which not only knows the addressof each segment, but also can determinethe best path for sending data andfiltering broadcast traffic to the localsegment. Such device is called a Router.A router is a device in computernetworking that forwards data packets totheir destinations, based on their

addresses. The work a router does itcalled routing, which is somewhat likeswitching, but a router is different from aswitch.

Routers work at the Network layer of the OSI model meaning that the Routerscan switch and route packets across multiple networks. They do this by exchanging

protocol-specific information between separate networks. Routers have access tomore information in packets than bridges, and use this information to improve packetdeliveries. Routers are usually used in a complex network situation because they

provide better traffic management than bridges and do not pass broadcast traffic.Routers can share status and routing information with one another and use this

information to bypass slow or malfunctioning connections. When data packets are

transmitted over a network (say the Internet), they move through many routers

(because they pass through many networks) in their journey from the source machine

to the destination machine. Routers work with IP packets, meaning that it works at the

level of the IP protocol.

Each router keeps information about its neighbors (other routers in the same orother networks). This information includes the IP address and the cost, which is interms of time, delay and other network considerations. This information is kept in arouting table, found in all routers.

Routers do not look at the destination node address; they only look at thenetwork address. Routers will only pass the information if the network address is


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known. This ability to control the data passing through the router reduces the amountof traffic between networks and allows routers to use these links more efficiently than

bridges . Unlike bridges and switches, which use the hardware-configured MACaddress to determine the destination of the data, routers use the logic network addresssuch as IP address to make decisions.

2.6 Network Interface Card (Ethernet)

Network interface cards (NICs) are installed in a computer to allow it tocommunicate with a network.They provide a transparentinterface between the networkand the computer.

An Ethernet networkinterface card is installed in anavailable slot inside thecomputer. The NIC assigns aunique address called a MAC(media access control) to themachine. The MACs on thenetwork are used to direct traffic

between the computers. The back plate of the network interface card features a portthat looks similar to a phone jack, but is slightly larger. This port accommodates anEthernet cable, which resembles a thicker version of a standard telephone line.Ethernet cable must run from each network interface card to a central hub or switch.The hub or switch acts like a relay, passing information between computers using theMAC addresses and allowing resources like printers and scanners to be shared alongwith data.

NICs come in many shapes and sizes. They can be installed internally orexternally, although an internal installation is more likely. The picture illustrates aninternally installed combo (more than one type of connection) card. This card issomewhat unusual in that it supports three connections:

The upper connection is an RJ45 female forUTP media.

The middle connection is a BNC connector for thin coaxial media.

The lower connection is a DB-15 connector for a thick Ethernet viper tap.

In order for a NIC to operate effectively, it must be able to carry out its interfacetasks with minimum disruption to the CPU of the computer in which it is installed.Four methods of NIC to computer data transfer are used:

Bus mastering DMA (direct memory access):

Data enters the NIC from the network.

The NIC's own CPU stores data in the NIC's RAM.

NIC's CPU sends data to computer's motherboard when the network

transmission is complete.


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The computer's CPU is not interrupted - the NIC's CPU has ultimate

responsibility for data transfer.

DMA:


The NIC's CPU interrupts the computer's CPU.

The computer's CPU stops other tasks and transfers the network data

into its RAM.

Programmed I/O (input/output):


The NIC's CPU loads the network data into a motherboard I/O address.

The computer's CPU checks the I/O address for any network data.

If there is any data, the computer's CPU transfers the data to its RAM.

Shared memory:


The NIC's CPU stores the data in the NIC's RAM.

The NIC's CPU interrupts the computer's CPU.

The computer's CPU stops other tasks and transfers the network data

into its RAM.

2.7 Modem

A modem (modulator-demodulator) is a device thatmodulates an analog carrier signal toencode digital information, and alsodemodulates such a carrier signal todecode the transmitted information.The goal is to produce a signal thatcan be transmitted easily and decodedto reproduce the original digital data. Modems can be used over any means oftransmitting analog signals, from driven diodes to radio.

The most familiar example is a voice band modem that turns the digital data of

a personal computer into analog audio signals that can be transmitted over a telephoneline. Modems are generally classified by the amount of data they can send in a giventime, normally measured in bits per second (bit/s, or bps). They can also be classified

by Baud, the number of times the modem changes its signal state per second.

Asymmetric Digital Subscriber Line (ADSL) is one form of the DigitalSubscriber Line technology, a data communications technology that enables fasterdata transmission over copper telephone lines than a conventional voice band modemcan provide. It does this by utilizing frequencies that are not used by a voice telephonecall. Currently, most ADSL communication is full-duplex. Full-duplex ADSLcommunication is usually achieved on a wire pair by either frequency-division duplex(FDD), echo-cancelling duplex (ECD), or time-division duplex (TDD). With standardADSL, the band from 26.000 KHz to 137.825 kHz is used for upstreamcommunication, while 138 kHz 1104 kHz is used for downstream communication.


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2.8 VoIP (Voice over Internet Protocol)

VoIP (Voice over Internet Protocol) is simply the transmission of voice trafficover IP-based networks. VoIP is a general term for a family of transmission

technologies for delivery of voice communications over IP networks such as theinternet or other packed switched networks. VoIP systems employ session control

protocols to control the set-up and tear-down of calls as well as audio codec whichencode speech allowing transmission overan IP network on digital audio via anaudio stream.

There are three methods of connecting toa VoIP network:

Using a VoIP telephone

Using a "normal" telephone with a

VoIP adapter

Using a computer with speakersand a microphone

2.8.1 Types of VoIP Calls

VoIP telephone calls can be placed either to other VoIP devices, or to normaltelephones on the PSTN (Public Switched Telephone Network).

Calls from a VoIP device to a PSTN device are commonly called "PC-to-Phone" calls, even though the VoIP device may not be a PC.

Calls from a VoIP device to another VoIP device are commonly called "PC-to-PC" calls, even though neither device may be a PC.

2.9 Gateway

Gateways make communication possible between different architectures andenvironments. They repackage and convert data going from one environment toanother so that each environment can understand the other's environment data. Agateway repackages information to match the requirements of the destination system.Gateways can change the format of a message so that it will conform to theapplication program at the receiving end of the transfer.

A gateway links two systems that do not use the same:

Communication protocols

Data formatting structures

Languages

Architecture

For example, electronic mail gateways, such as X.400 gateway, receive messagesin one format, and then translate it, and forward in X.400 format used by the receiver,and vice versa.


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2.10 Connectors RJ 45Registered Jack-45, an eight-wire

connector used commonly to connectcomputers onto Local-area networks (LAN),especially Ethernets.

2.9.1 Configuring straight and cross patchcords:

Straight connection:It is used in LAN

End1 End 2

1. White(orange) 1. White(orange)

2. Orange 2. Orange

3. White(green) 3. White(green)

4. Blue 4. Blue

5. White(Blue) 5. White(Blue)

6. Green 6. Green

7. White(Brown) 7. White(Brown)

8. Brown 8. Brown

Cross connection: It is used in computer to computer data transform.

End1 End 2

1.White(orange) 1.White(Green)

2.Orange 2.Green

3.White(green) 3.White(Orange)

4.Blue 4.Blue

5.White(Blue) 5.White(Blue)

6.Green 6.Orange

7.White(Brown) 7.White(Brown)

8.Brown 8.Brown


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2.11 Direction of transmission or Data Flow:

Communication between two devices can be simplex, half duplex, and full duplex.


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2.11.1 Simplex

In simplex mode, the communication is unidirectional, as on a one way street.

Only one of the two devices on a link can transmit; the other can only receive. Inother words, Simplex refers to one-way

communications where one party is the

transmitter and the other is the receiver.

An example: simple radio, which you

can receive data from stations but can't

transmit data. Keyboards and

Traditional Monitors are example of

simplex devices. The keyboard can only introduce input; the monitor can only accept

output.

2.11.2 Half-Duplex

In half-duplex mode, each station can both transmit and receive, but not at the

same time. When one device is sending, the other can only receive, and vice versa. It

refers to two-way communications

where only one party can transmit at a

time. I.e. in both directions but one at a

time. The entire capacity of a channel is

taken over by whichever of the two

devices is transmitting at the time. The

half-duplex mode is used in cases

where there is no need for communication in both directions at the same time.

Example: a walkie-talkie and CB(citizen band)radios .

2.11.3 Full-Duplex

Full-Duplex:-In full duplex mode, both stations can transmit and receive

simultaneously. It refers to the transmission of data in two directions simultaneously.

For example, a telephone conversation

because both parties can talk and listen at

the same time. In full duplex mode signals

going in either direction share the capacity

of the link. It can occur in two ways either

two separate physical paths or the capacity

of the channel is divided between signals

traveling both directions.


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3. TRANSMISSION MEDIUM

A transmission medium is a material substance (solid, liquid or gas) whichcan propagate energy waves. For example, the transmission medium for soundreceived by the ears is usually air, but solids and liquids may also act as transmission

media for sound. In other word, the transmission medium is the physical path bywhich a message travels from sender to receiver. Example of Transmission mediainclude twisted pair wire, coaxial cable, fiber-optic cable, and radio waves. Theabsence of a material medium (the vacuum of empty space) can also be thought of asa transmission medium for electromagnetic waves such as light and radio waves.Signals are usually transmitted over some transmission media that are broadlyclassified in to two categories:-

3.1 Unguided Media:

This is the wireless media that transport electromagnetic waves without usinga physical conductor. Signals are broadcast through air. This is done through radiocommunication, satellite communication and cellular telephony.

3.2 Guided Media:

These are those that provide a conduit from one device to another that includetwisted-pair, coaxial cable and fiber-optic cable. A signal traveling along any of thesemedia is directed and is contained by the physical limits of the medium. Twisted-pairand coaxial cable use metallic that accept and transport signals in the form ofelectrical current. Optical fiber is a glass or plastic cable that accepts and transportssignals in the form of light.

3.3 Twisted-Pair Cable :

A twisted pair consists of two conductors (normally copper), each with its ownplastic insulation, twisted together, as shown in Figure.

One of the wires is used to carry signals to the receiver, and the other is used only as aground reference. The receiver uses the difference between the two. In addition to thesignal sent by the sender on one of the wires, interference (noise) and crosstalk mayaffect both wires and create unwanted signals. If the two wires are parallel, the effectof these unwanted signals is not the same in both wires because they are at differentlocations relative to the noise or crosstalk sources (e.g., one is closer and the other isfarther). This results in a difference at the receiver. By twisting the pairs, a balance ismaintained. Twisted-pair cable used in communications is categories in two differentcategories :


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3.3.1 UTP

The most common twisted-pair cable used in communications is referred to asunshielded twisted-pair(UTP).

3.3.2 STP

IBM has also produced a version of twisted-pair cable for its use calledshielded twisted-pair(STP). STP cable has a metal foil or braided-mesh covering that

encases each pair of insulated conductors. Although metal casing improves the qualityof cable by preventing the penetration of noise or crosstalk, it is bulkier and moreexpensive

3.4 Coaxial cable

Coaxial cable, or coax, is an electrical cable with an inner conductor

surrounded by a flexible, tubular insulating layer, surrounded by a tubular conducting

shield.

Coaxial cable is used as a transmission line for radio frequency signals, in

applications such as connecting radio transmitters and receivers with their antennas,

computer network (Internet) connections, and distributing cable television signals.

One advantage of coax over other types of transmission line is that in an ideal coaxial

cable the electromagnetic field carrying the signal exists only in the space between the

inner and outer conductors. This allows coaxial cable runs to be installed next to

metal objects such as gutters without the power losses that occur in other transmission

lines, and provides protection of the signal from external electromagnetic interference.


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3.5 Optical Fiber

An optical fiber cable is a cable containing one or more optical fibers. Theoptical fiber elements are typically individually coated with plastic layers andcontained in a protective tube suitable for the environment where the cable will be

deployed. Optical Fiber consists of thin glass fibers that can carry information atfrequencies in the visible light spectrum and beyond.

The typical optical fiber consists of a very narrow strand of glass called theCore. A typical Core diameter is 62.5 microns (1 micron = 10-6 meters). Around theCore is a concentric layer of glass called the Cladding. Typically Cladding has adiameter of 125 microns .Coating the cladding is a protective coating consisting of

plastic, it is called the Jacket. Its purpose is to provide protection for the cladding andcore against such hazards as abrasion and moisture.

There are 3 primary types of transmission modes using optical fiber: They area) Step Mode Index

b) Graded Mode Indexc) Single Mode Index

Step Mode Index has a large core the light rays tend to bounce around,

reflecting off the cladding, inside the core. This causes some rays bounce back and

forth taking a longer path. Some take the direct path with hardly one reflections taking

shorted path.

The result is that the light rays arrive at the receiver at different times. The

signal becomes longer than the original signal. Typical Core diameter is 62.5 microns

and cladding diameter is 125 microns. LED light sources are used.

Graded Mode Index has a gradual change in the Core's Refractive Index.

This causes the light rays to be gradually bent back into the core path. This is


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represented by a curved reflective path. The result is a better receive signal than Step

Index. Typical Core diameter: 42.5 microns & cladding diameter 145.5 microns. LED

light sources are used.

Single Mode Index has separate distinct Refractive Indexes for the cladding

and core. The light ray passes through the core with relatively few reflections off the

cladding. Single Mode is used for a single source of light (one color) operation. The

core diameter is very small: 9 microns & cladding diameter is 177.5 microns. It

requires a laser.

3.6 Comparison of Different mode of Optical Fibers:


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4. TRANSMISSION IMPAIRMENT

Signals travel through transmission media, which are not perfect. Theimperfection causes signal impairment. This means that the signal at the beginning ofthe medium is not the same as the signal at the end of the medium. What is sent is notwhat is received. Three causes of impairment are attenuation, distortion, and noise.

4.1 Attenuation

Attenuation means a loss of energy. When a signal, simple or composite,travels through a medium, it loses some of its energy in overcoming the resistance ofthe medium. To compensate for this loss, amplifiers are used to amplify the signal.Figure shows the effect of attenuation and amplification.

Decibel

To show that a signal has lost or gained strength, engineers use the unit of the

decibel. The decibel (dB) measures the relative strengths of two signals or one signalat two different points. Note that the decibel is negative if a signal is attenuated and

positive if a signal is amplified.

dB =10 log10 p2/p1

4.2 Distortion

Distortion means that the signal changes its form or shape. Distortion canoccur in a composite signal made of different frequencies. Each signal component has

its own propagation speed (see the next section) through a medium and, therefore, itsown delay in arriving at the final destination. Differences in delay may create adifference in phase if the delay is not exactly the same as the period duration. In otherwords, signal components at the receiver have phases different from what they had atthe sender. The shape of the composite signal is therefore not the same. Figure showsthe effect of distortion on a composite signal.


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4.3 Noise

Noise is another cause of impairment. Several types of noise, such as thermalnoise, induced noise, crosstalk, and impulse noise, may corrupt the signal. Thermalnoise is the random motion of electrons in a wire which creates an extra signal notoriginally sent by the transmitter. Induced noise comes from sources such as motors

and appliances. These devices act as sending a antenna, and the transmission mediumacts as the receiving antenna. Crosstalk is the effect of one wire on the other. Onewire acts as a sending antenna and the other as the receiving antenna. Impulse noise isa spike (a signal with high energy in a very short time) that comes from power lines,lightning. Figure shows the effect of noise on a signal.

4.3.1 Signal-to-Noise Ratio (SNR)

As we will see later, to find the theoretical bit rate limit, we need to know theratio of the signal power to the noise power. The signal-to-noise ratio is defined as

SNR = average signal power/average noise power

SNR is actually the ratio of what is wanted (signal) to what is not wanted (noise). Ahigh SNR means the signal is less corrupted by noise; a low SNR means the signal ismore corrupted by noise. As SNR is the ratio of two powers, it is often described indecibel units, SNR dB , defined as

SNRcm =10 log10 SNR4.3.2 Throughput


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The throughput is a measure of how fast can send data through a network. Inother words, the bandwidth is a potential measurement of a link, the throughput is anactual measurement of how fast data can send.

5. ACCESS POINT

An access point is nothing but a router that releases IP. Access point gets its IPaddress range from the port address of the switch as port of switches are configured

according to VLAN. Access points are configured and installed according o the signal

location etc.

They have 14 broadcasting channels of 22 MHz each and separated by 5 MHz

guard band. If two devices come under same channel then they will establish path in a

loop with each other. In this case they can communicate with each other only and not

with any other device. All access points are connected to managed switch from where

DHCP server is connected in data centre. From access points stations are connected.

We can also configure access point as DHCP server. Access points can release up to amaximum of 60 IP addresses and it varies with the device. Access point devices can

configure MAC address within itself. Access points are distinguished by SSID

(Service Set Identifier) and we can have multiple SSID to allocate particular

bandwidth. It also helps in managing access points. Access points are mainly used in

Wi-Fi technology to transmit data to and from wireless clients.

5.1 What is Wi-Fi?

Wi-Fi stands forwireless fidelity. It is a wireless technology that uses radio

frequency to transmit data through the air. Wi-Fi standards use the Ethernet protocoland CSMA/CD (Carrier Sense Multiple Access with Collision Detection) for path

sharing. In short wi-fi is meant to be used generically when referring to any type of

802.11 networks.

Access points are configured using the 802.11 standards. 802.11 refers to a

family of specifications developed by IEEE for wireless LAN technology. 802.11

specifies an over-the-air interface between a wireless client and a base station or

between two wireless clients. There are several specifications in 802.11 family:-

802.11a

802.11b

802.11e

802.11f

802.11g

802.11h

802.11i


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802.11

The original WLAN standard. Supports 1Mbps to 2 Mbps.

Spectrum 2.4 GHz.

Layer 3 data rate 1.2Mbps.

Transmission FHSS/DSSS.

Limited bit rate but higher range.

802.11a

High speed WLAN standard for 5 GHz band spectrum.

Supports 54 Mbps.

Layer 3 data rate 33Mbps.

Transmission through OFDM.

Smallest range of all 802.11 standards but higher bit rate in

less crowded spectrum.

802.11b

WLAN standard for 2.4 GHz band.

Supports a maximum of 11 Mbps. Layer 3 data rate 6-7 Mbps.

Transmission by DSSS.

Compatible with 802.11

Widely deployed due to higher range but bit rate is too slow

for many emerging applications.

802.11e

Address quality of service requirements for all IEEE WLAN

radio interfaces.

802.11f

Defines inter-access point communications to facilitatemultiple vendor-distributed WLAN networks.

802.11g

Establishes an additional modulation technique for 2.4 GHz

band.

Intended to provide speeds up to 54 Mbps.

Layer 3 data rate is 32 Mbps.

Transmission through OFDM.

Compatible with 802.11 and 802.11b due to narrow

spectrum.

Includes much greater security.

802.11h Defines spectrum management of 5 GHz band for use in

Europe and Asia Pacific.

802.11i Address the current security weakness for both authentication

and encryption protocols.

The standard encompasses 802.1X, TKIP, and AES

protocols.

.


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5.2 Types of Access Points:

Different types of access points are available in the market now-a-days like-

Avaya AP-6, Motorola AP-5131, D-Link DWL-3200AP, Cisco, Linksys etc.

5.2.1 Motorola AP-5131:

Electrical Characteristics :

Operating Voltage 48 Vdc (Nom)

Operating current 200 mA (Peak) @ 48 Vdc

170 mA (Nom) @ 48 Vdc

Radio Characteristics :

Transmitter Power 22 dBm Maximum (country, channel and data

rate dependent)

802.11b/g

19 dBm +/- dBm @1, 2, 5.5, 11 Mbps

19 dBm +/- dBm @6 and 9 Mbps




802.11a

17 dBm +/- dBm @6 and 9 Mbps16 dBm +/- dBm @12 and 18 Mbps



Operating Channels 802.11a radio- Channels 1-35 (4920-5825 MHz)

802.11b/g radio- Channels 1-13 (2412-2472

MHz)

Radio Data Rates 802.11a radio 6, 9, 12, 18, 24, 36, 48 and 54

Mbit/sec


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om/


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802.11g radio 6, 9, 12, 18, 24, 36, 48 and 54

Mbit/sec

802.11b radio 1, 2, 5.5, 11 Mbps

Wireless Medium Direct Sequence Spread Spectrum (DSSS)

Orthogonal Frequency Division Multiplexing

(OFDM)

Antenna Options :

Both Radio 1 and Radio 2 require 1 antenna and can optimally use two

antennas per radio (4 antennas total for dual-radio models). Two antennas per radio

provide diversity that can improve performance and signal reception. Motorola

supports 2 antenna suites for the AP-5131. Radio 1 supports the 2.4 GHz radio and

Radio 2 refers to the AP-5131 5.2 GHz radio. However, there could be some cases

where a dual-radio AP-5131 is performing a Rogue AP detector function. In this

scenario, the AP-5131 is receiving in either 2.4 GHz or 5.2 GHz over Radio 1 or

Radio 2 antennas depending on which radio is selected for the scan.

LED indicators :

AP-5131 utilizes seven LED indicators. Five LEDs display within four LED

slots on the front of the AP-5131 (on top of the AP-5131 housing) and two LEDs (forabove the ceiling installations) are located on the back of the device (the side

containing the LAN, WAN and antenna connectors). The five AP-5131 top housing

LEDs have the following display and functionality:-

Boot and Power Status Solid white indicates the AP-5131 is adequately

powered.

Error Conditions Solid red indicates the AP-5131 is experiencing

a problem condition requiring immediate

attention.


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Ethernet Activity Flashing white light indicates data transfers and

Ethernet activity.

802.11a Radio Activity Flickering amber indicates beacons and data

transfers over the AP-5131 802.11a radio.

802.11b/g Radio Activity Flickering green indicates beacons and data

transfers over the AP-5131 802.11b/g radio.

The LEDs on the rear of the AP-5131 are viewed using a single (customer

installed) extended light pipe, adjusted as required to suit above the ceiling

installations. The LEDs displayed using the light pipe have the following colour

display and functionality:-

Boot and Power Status Solid white indicates the AP-5131 is adequately

powered.

Error Conditions Blinking red indicates the AP-5131 Rogue AP

Detection feature has located a rogue device.

Solid red indicates the AP-5131 is experiencing

a problem condition requiring immediate

attention.

5.3 AP-5131 Configuration :

1. Start browser and enter the following IP address in the address field

http://10.1.1.1

The AP-5131 login screen displays.


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2. Log in using admin as the default user ID and motorola as the default

password. If the default login is successful, the Change Admin Password

window displays.

3. Change the password.

To define basic AP-5131 configuration:

1. Select System Configuration Quick Setup from the AP-5131 menu tree.

2. Enter a System Name for the AP-5131. The system name is useful ifmultiple devices are being administered.

3. Select the Country for the AP-5131s country of operation from the drop-

down menu.

The AP-5131 prompts the user for the correct country code on the first login. A

warning message also displays stating that an incorrect country setting may result in

illegal radio operation. Selecting the correct country is central to legally operating the

AP-5131. Each country has its own regulatory restrictions concerning electromagnetic

emissions and the maximum RF signal strength that can be transmitted. To ensure

compliance with national and local laws, be sure to set.


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4. Optionally enter the IP address of the server used to provide system time to the

AP-5131 within the Time Server field.

Once the IP address is entered, the AP-5131s Network Time Protocol (NTP)

functionality is engaged automatically.

5. Click WAN tab to set minimum set of parameters for using the WAN

interface.

a. Select the Enable WAN Interface checkbox to enable a connection

between the AP-5131 and a larger network or outside world through the

WAN port. Disable this option to effectively isolate the AP-5131s WAN

connection. No connections to a larger network or the internet will be

possible. MUs cannot communicate beyond the configured subnets.

b. Select the This Interface is a DHCP Client checkbox to enable DHCP for

the AP-5131 WAN connection. This is useful, if the target corporaten

41205950 networking and servers

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