III - Configure Computer Systems and Networks

7/30/2019 III - Configure Computer Systems and Networks

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Unit of Competency Configure Computer Systems and Networks ELC724320 CN 25Module Title Configuring Computer Systems and Networks Page 1 of 42

ICT DepartmentPHILCOMTECH BalagtasSauco Francisco Building, B.S. Aquino Ave., Bagong Nayon,Baliuag Bulacan

Computer

Networking BasicKey Concepts in Computer Networking

In the world of computers, networking is the practice of linking

two or more computing devices together for the purpose of sharing data.Networks are built with a mix of computer hardware and computersoftware.

There are many reasons why a person would like to setup abasic network. These reasons range from sharing multimedia, playinggames, sharing a single printer, or most commonly, sharing a high speedinternet connection.

Most homes nowadays have more than one PC, and sharing your highspeed internet connection gives you the most bang for your buck. Settingup a network will allow all computers in one house to share and use theinternet at the same time.

Now, if you are going to tackle the task of setting up a basic network, youhave to ask yourself one question first; do you want a wired or wirelessnetwork? Each have their benefits and choosing between the two may beharder than setting up the network itself, but their still might be some lightat the end of the tunnel for all of you.

A wireless network allows you more freedom; after all, you are no longerbound by wires. Also, being wireless means that you don't have to stringwires through your floors or walls, allowing you to possible set up anetwork across the house a little easier. Although wireless networks cantypically cost twice as much as wired networks, it is becoming more andmore common among home users. Especially for those who enjoy

surfing the internet on their laptop while basking in the sun by the pool.

Configure ComputerSystem and

Networks

+ + + +

Plan and Preparefor

configuration

ConfigureComputer

Systemsand Networks

Inspectand test

configuredcomputersystemand Networks


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Basic Computer Network Information

Introduction

A network is a group of things that are connected together. In a computer network, the things that are connectedare computers, of course. A computer network can be as small as two computers but there is no maximum size,and many networks have hundreds or thousands of computers.

There are three main reasons for connecting computers in a network:

1. Share information. This can be messages such as e-mail, or it can be files that are stored on onecomputer and used by someone at a different computer.

2. Share resources. A printer that can be accessed from different computer systems is a shared resource.So is an Internet connection used by more than one computer.

3. Centralized control. In most offices, the management determines what the computers may be used forand what kind of resources and support they need. This is much easier to deal with if the computers areconnected.

Types of Networks

Just as there is no limit to the number of systems in a network, there is also no limit to the geographical size of anetwork. As a practical matter though, there are some structural differences between a network of computers all inthe same room, and a network connecting computers in Los Angeles to ones in Sydney Australia.

The most common network includes computers that are close together, usually in the same building or office. Thisis called a Local Area Network, abbreviated LAN.

The computers in a LAN are usually connected with cable made up of pairs of wires, but faster (and moreexpensive) cables are made from glass fibers, called fiber optic cable. A network may even use radio waves, in

which case it is a wireless LAN.

When the computers being connected are far apart, typically in different cities, it is called a WAN orWide AreaNetwork. The connection is usually done with special high-speed lines leased from the phone company, but it isalso possible to connect over an ordinary phone line using a device called a modem. Its slow, but possible.

Accessing a network through a phone line and modem is called a dial-up connection.

The biggest of all networks is the Internet. The backbone of the Internet consists of powerful computers all overthe world with high-speed connections between them. Individual computers such as yours then connect to thisbackbone through an Internet Service Provider orISP.

Ethernet

Most LANs in existence today use a technology called Ethernet. In an Ethernet network, every piece ofinformation put on the network is seen by every other computer on the network, and each computer mustdetermine if that information is meant for itself.



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To make this work, before the information goes out on the network it is first broken up into small pieces calledpackets, and each packet has added to it the address of the computer that should receive it. The part of thepacket containing the address is called the header.

Header

Packet diagram

Then, each computer looks at the address on each packet that comes by on the network cable, and copies theones that have the right address. The computer that sent the packet is called the source, and the one that issupposed to receive it is called the destination.

Network Connections

When a packet comes out of the computer that originated it, that packet must have a complete electrical path toevery other computer. The simplest way to do this is to have a cable that goes from one computer to the next untilit has connected to each one. This is called a bus network.

Bus Network

A bus network is the simplest to explain and draw, but its not often the simplest one to use, especially ifcomputers are distributed around various offices in a building, and then get added, taken away, moved aroundand so forth.

A much more practical way to connect more than a couple of systems is to connect each one to a device called ahub. Each system has a cable that goes from it to the hub, and inside the hub an electrical connection is madebetween all of the cables. Each place where a cable plugs into the hub is called a port.



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5-porthub ports

To create larger networks, hubs can use one or more of their connections to connect to other hubs. This is calleda star network, but as far as the electrical signals are concerned, they go from one computer to every othercomputer, no different than the bus network.

3-hub star network

When networks get really big, with 100s of systems or more, its no longer such a good idea to have eachcomputer look at every packet, because almost none of the packets will be for that computer. The large networkcan be broken up into smaller groups called subnets, and these are connected with a device called a dataswitch, or just a switch.

Within each subnet, all of the computers still see every packet, and so does the switch. Normally the switch wontpass those packets on to the other subnets, but if the packet has an address for a destination in another subnet,the switch will pass the packet to the port for that subnet. All of the systems in that subnet will then see the

packet, including the system it is actually addressed to. In order to know where to send a packet, the switch musthave a table of addresses for each subnet.



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Switch with 4 subnets

The simplest form of a switch is called a bridge, and it connects just two subnets. A bridge only needs two portsthen, one for each of the subnets.

Sometimes a network will be so big and complex that one switch isnt enough to connect all of the subnets. In thatcase the subnet receiving a packet might be connected to a different switch than the subnet where the packetstarted. This is a more complicated problem, because the switch would need to know not only the packetsdestination, but also where to send it next to make sure it got there.

For this, a smarter device is needed, called a router. The router needs to know not only the subnet addresses,but also the best path, or route, to get from one to another.

Route path diagram

One place where routers are used in a big way is the Internet. If you send a message on the Internet, it might gothrough many routers before it reaches its destination. And when you surf to a website, all of the graphics and textshowing up on your screen had to go through routers to find their way from the web site to your computer.



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By the way, every LAN that connects to the Internet becomes a subnet of the Internet, even if it has its owninternal subnets.

Clients and Servers

In addition to the various ways networked systems can be physically connected, there are two basic ways that

network activities can be arranged. In one, all of the computers have equal status. This is called peer-to-peer,because a peer means someone (or something) that is the equal of another. Peer-to-peer is used mostly in verysmall networks of less than a dozen systems.

The more common arrangement is called client-server. One system, called the server, is responsible for aparticular activity or resource. The other systems are called clients, and they go through the server when theywant to use the function or resource that the server is responsible for.

Some of the things servers are commonly used for include network administration, e-mail, printers, file storage,and Internet access. Often several of these functions will be combined into one machine. There is no rule thatsays a network server and a print server cant be the same system.

Clients Server

print server

There is also no rule that says a server must serve the entire network. It is usually convenient to have a separatenetwork server for each subnet. There are other divisions that can occur even within a subnet. Computers thatneed to share the same resources can be organized into workgroups. With the Windows NT operating system,

the LAN can be divided into sections called domains, and each domain needs its own server called a domaincontroller.

Protocols

A protocol is an agreed-upon standard for how something will be done. When your mother taught you to chewwith your mouth closed and keep your elbows off the table, that was a protocol for proper dining. Computerprotocols are the rules for connecting with other computers and exchanging information with them.

Ethernet is a protocol. Earlier we called it a technology, but it is also a set of rules for how that technology is used.If each piece of hardware and software complies with the rules, then information can be correctly transferred fromone from one system to another in a LAN.

There are many protocols used in networking. There are some protocols that are used together with otherprotocols, where each one takes care of different aspects of networking. Sometimes two protocols do the samething in different ways, and it is necessary to choose one or the other. The important thing is that both systemstrying to communicate with each other have matching protocols that they can use.



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TCP/IP

One very important set of protocols is called TCP/IP. It is important because it is what the creators of the Internetdecided would be used for that particular network, which means that any computer that wants to connect to theInternet must also use TCP/IP. TCP/IP stands forTransmission Control Protocol / Internet Protocol.

TCP/IP is actually in two parts. The TCP portion covers the agreements between systems about how they willcarry on their conversation, and the IP portion deals with addressing the packets and routing them.

The TCP part all happens in the background and we dont really need to concern ourselves with it under normalcircumstances. However, in a network that uses TCP/IP, every system must have a unique IP address, and thatis something that requires human intervention in one way or another.

IP Addresses

An IP address is made up of four sets of numbers separated by periods. An example is:

192.168.42.122

Each of these sets of numbers is called an octet, because they started out as 8-digit binary numbers. By changingthem into 3-digit decimal numbers, the whole address is shorter and easier to remember. The highest value forany octet is 255, because the highest number you can make with eight binary digits is equal to 255 in decimal.

In most networks, the first three octets are the same for all systems, and the last octet is different for everymachine. If there are more than 255 computers in a network, it is usually divided into smaller subnets.

Static or Dynamic?

There are two ways to associate a unique IP address to a specific computer. One way is for the administrator toassign a number, which stays the same unless somebody decides to change it some day. That number is then astatic IP address.

The other way is to assign a group of addresses to a server, and let the server hand them out as needed to anysystem that wants to communicate on the network. This produces a dynamic IP address. It is sometimesimportant to know which method is in use on a network, because with dynamic addressing, the IP address of amachine may be different each time you try to communicate with it.

Computer Names

The example address 192.168.42.122 is only one digit longer than a phone number with area code, but thatsplenty long enough to give most of us a hard time. Its much easier for people to remember a name instead of anumber, and for this reason computers in a network are also given a unique name. It may be something mundanelike Sales14, but at least its a name and not a number.

This is not only easier to remember, but it solves the problem of a dynamic address that changes all the time,because the computer name doesnt normally change. It does create another problem though, because thecomputers use only the addresses and not the names to keep track of each other. Fortunately there is a part of



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the TCP/IP protocol called address resolution, and it matches up the names and addresses so things keeprolling smoothly along.

Security

The problem with connecting computers to the Internet is that they are then sharing a network with many other

computers from all over the world, and the users of some of those other computers are not such nice folks.Protecting the network and the information on it is one of the most important parts of a network administrators

job.

Encryption

One way to protect information is to scramble it so that it appears to be gibberish unless someone has the rightkey to unscramble it. Scrambling it is called encryption, and unscrambling it is called decryption. There aremany ways to encrypt information, and of course just as many keys to decrypt it.

Encrypting and decrypting information slows things down a bit, so a decision must be made about when to use it.For packets going around the LAN, it depends on how likely it is that someone will gain unauthorized access tothe LAN, called hacking. It also depends on how much damage would be done if that happened. If the threat issevere, encryption can be done not only on the transmitted packets but also to information stored on the diskdrive.

For information going over the Internet, encryption is much more important unless its all right for the whole worldto see the information. If you send your credit card number to a vendor, you must trust that vendor to encrypt andsafeguard the information.

Virus Software

A computer virus is a little program that makes copies of itself to send to other computers. Its very similar in someways to contagious germs spreading a disease from one person to the next. And like diseases, some of thesecomputer viruses have some really nasty side effects, like wiping out important files in the operating system or

filling up the hard drive with garbage data.

As we will discuss a little later, there are ways to keep these virus programs from getting to your computer, butthey are not foolproof. A lot of viruses come in attached to e-mail, and then they will mail copies of themselves toeveryone in your e-mail address folder. You cant completely block them without blocking e-mail, and most of uslike to get e-mail from our friends and coworkers.

The most important prevention for viruses is to have a good anti-virus program installed on your computer.Norton, McCaffey and Panda are probably the most popular. The next most important thing is to keep the anti-virus software up-to-date, because the delinquents who write virus software are always coming up with new tricks,and the anti-virus companies are just as quickly coming up with new versions to stop them.

Access Control

If you have ever had a computer that was connected to a local area network, you almost certainly had to type in auser name and password to get network access. Its two forms of ID, just like when you cash a check atdepartment store.



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The network administrator used that identification information to determine what you could and couldnt do on thenetwork. And there may have been additional passwords to access the company customer database, employeepayroll records, or files stored on someone elses computer.

Here are a few tips about passwords:

1. First, if you share files on your computer, use password protection for them even if they are available toeveryone in the network. That way they cant be tampered with if a hacker breaks in.

2. In choosing a password, never use your name, your birthday or other obvious personal information. Thebest is a random combination of letters and numbers.

3. Commit the password to memory, and if you must write it down, hide it. A password written on a post-itnote stuck to your monitor is probably worse than no password at all.

4. Dont give your password to someone you dont know personally just because they claim to be techsupport, the phone company, the police or your long-lost Aunt Matilda. Refer them to the networkadministrator, or better yet, get their phone number and have the network administrator call them back.

Firewalls

In a building, a firewall is a wall to keep fire from spreading from one area to another. In a computer network, a

firewall is a boundary that can block unwanted data packets. The firewall may be program running on the serveror router, or it may be a separate piece of hardware or even a complete computer system just for that purpose. Inany case, its purpose is to look at all of the packets coming through, and decide which ones can pass and whichones get blocked.

Ports Several pages ago, we defined a port as the place in a hub that a cable plugs into. There is anothercompletely different kind of thing called a port, and that is a location in a computers memory that is used by adevice or application to send and receive data. Each application will have one (or more) of these locations for itsown use.

For instance, there is a common e-mail program that has port # 110, which means that the program exchangesinformation with the rest of the system at memory location 110. The popular game called Doom uses port # 666.

When a packet is sent over a network, it will contain not only the destination address, but also the port number ofthe application that will use it at that destination. One of the ways a firewall controls the packets is by looking atthe port number, and only passing packets with ports that are appropriate for the destination. If nobody should beplaying Doom on the networks computers, then it would make sense to block port 666.

Another way a firewall can control traffic is to look at the source of the packet. It can have a prohibited list thatkeeps out packets from certain IP addresses, or it can have an allowed list and block everyone who isnt on it.Ports can be done the same way, with a prohibited or allowed list of ports.

Conclusion

There is much more to know about security, and about networks in general, if one is to be involved in managing

them. The purpose of this paper is to present just enough information to enable you talk with networkadministrators and to understand their concerns when presenting network products to them. For additionaltraining in this subject, we recommend the Micro2000 A+ and Network+ courses.



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Terms for Networking Course

802.11: The IEEE standard for wireless networking.

Access point : The transceiver where a wireless node connects to the network. Also the control system in aHyperLAN network.

Activation: The process of validating the Console and Client seat license information.

administrator: The person in charge of managing a system or network.

Advanced Encryption Standard : A 128-bit encryption used by some government agencies. Abbreviated AES.Compare to DES, Data Encryption Standard.

alphanumeric: Consisting of letters and numbers. Names used in NT and RemoteScope must be made ofalphanumeric characters, with no spaces, symbols or punctuation except the dash and underscore.

Anti-virus Software: A utility to detect the intrusion of virus programs and limit their damage.

Application: A computer program to perform a specific task for the user, as opposed to the operating system thatruns the computer itself.

Architecture : The way something is built. Network architecture refers to the various ways a network can be put

together or implemented.

ASCII : American Standard Code for Information Interchange : A digital code for transmitting characters. Theformat used by personal computers for data exchange.

Back Office : See Microsoft Back Office.

Bandwidth : The carrying capacity of a data channel, usually expressed in bps (bits per second). Also calledthroughput or transfer rate.

bit : The smallest unit of information in a computer, either a zero or a one.

Boot ROM : A ROM chip added to a network card that allows a system with no local disk drive to access and bootfrom an operating system residing on the server.

Bootleg : Something made or used illegally or without authorization. In software it refers to additional copiesinstalled on computers other than the one for which the software was licensed.



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Bottleneck : A portion of a system or network that is slower than the rest of the data path, either because of itsthroughput speed or because of multiple data streams converging at that point.

bps : Abbreviation for bits per second.

Bps : Abbreviation for bytes per second.

Bridge: a device for passing signals between two LANs or two segments of a LAN.

Broadcasting: Sending a message simultaneously to all systems of a network, without requiring anacknowledgement. Compare to multi-casting.

brouter : A device combining the capabilities of a bridge and a router.

Browser : A program that allows viewing of HTML pages.

byte : A unit of digital data consisting of eight bits.

CAT 5 : The twisted-pair cable normally used for networks.

Cisco : A large supplier of networking hardware and software, including router and security products.

Client : 1. A workstation in a client-server network. 2. A system controlled by the Remote-Scope Console.

Client-server network : An arrangement where some programs, files or other resources are located on onecomputer, called the server, but are available to other systems on the network, called clients.

Command line : In a text-based operating system, the line on which the user types instructions for the system.

Compression : A method of compacting data for storage or transfer.

Configuration : The way the parts of a system or network are arranged or connected.

Console : The primary RemoteScope program from which Clients are controlled. Also, the workstation on which itis installed.

Data Encryption Standard : A common 56-bit encryption standard, and the one used by RemoteScope.Abbreviated DES.

Data switch : A device used to connect multiple networks or segments. It differs from a hub in that packets arerouted to the proper port rather than being broadcast on all ports.

Dial-up connection : Accessing a network or the internet through a modem attached to a standard phone line.

Direct connection : The local connection to a network made by a network card, as opposed to the remoteconnection made by a modem.



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Distribution : Copying a file or software package to multiple Client systems.

DNS : Domain Name System.

Domain : An area under a single point of control. On the Internet there are different levels of control and each is adomain. At the lowest level is each local area network that has its own network ID. Top-level domains are .com,

.org etc. In some operating systems such as NT, a domain is a group of associated computers within a LAN.

Domain Name System (also Domain Name Service): An Internet service that translates the domain namesused by people into the numeric IP addresses used for routing on the Internet. The domain name system isactually a network of domain name (DNS) servers.

Download : Copy a file from another computer to one's own, over a network or from the Internet.

Driver : A file containing information the operating system needs to interact with a hardware device or softwaremodule. In the case of hardware, it is usually called a device driver.

Dynamic addressing : Assigning IP addresses as needed from a pool of available addresses maintained on aserver, rather than assigning a fixed IP address to each system.

Encryption : Encoding data to protect it from being intercepted by unauthorized persons. RemoteScope encryptsall data transmissions, all password and user name information, and some application files.

Ethernet : A widespread standard for local area networks. There are versions for coaxial cable, twisted paircable, fiber optic cable and wireless.

Exporting : Outputting report information in another format, to be used in a different application. RemoteScopeprovides nearly 40 formats and variations for exporting report information.

Firewall : A barrier in a network that will only pass packets authorized to reach the other side.

Frame : A data structure used in network transmissions, consisting of one or more headers and a footerbracketing a data packet.

Full Control : One of the three remote control modes. Only the user of the Console will be able to enterkeystrokes and mouse movements for the Client machine. The user at the Client has no keyboard or mousecontrol.

Group : A collection of RemoteScope Clients assembled into a unit for common access. Actions can be takenwith all clients in a group simultaneously instead of one at a time.

Header : Data that comes in front of a data packet, containing address and handling information for that packet.

HTML : HyperText Markup Language. A program language for writing web pages that can include links to otherpages.

HTTP : HyperText Transfer Protocol. The standard for accessing HTML pages.



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Hub : A device providing a central point of connection for network cables.

I/O port : A hex memory address used by a device or program to exchange data with the rest of the computersystem.

IEEE 802.11 : A common standard for wireless networking, issued by the IEEE.

Internet : A cooperative system linking computer networks worldwide.

Inventory : A list of the installed hardware, applications and operating system for a particular system, maintainedin a database at the Console.

Internet Protocol : The portion of the TCP/IP suite that specifies packet formatting, naming and routing.Abbreviated IP.

IP address : A 32-bit number designating an individual machine on a network or on the Internet. It is usually listedas four groups of three-digit decimal numbers.

IPv6 : A plan for expansion of the domain name system. It stands for Internet Protocol version 6.

IRQ : Interrupt ReQuest. The signal that a peripheral or program uses to request service from the CPU. There are15 different IRQ values that can be used by system hardware.

ISP : Internet Service Provider. An organization providing access to the Internet.

ISS file : A file created for a silent or unattended install using InstallShield. It contains a record of all thekeystrokes required to complete the installation. ISS stands for InstallShield Silent Response.

LAN : Local Area Network. A group of computers connected to each other by cable or some form of wirelesstechnology, and usually located within the same building.

log on : Gain access as a current user of a system or network, usually by entering a user ID and password.

Mbps : Megabits per second. A data transfer rate of one million bits each second.

Messaging : A form of network communication that appears instantly on the monitor of the receiving system. Alsocalled instant messaging.

Microsoft Back Office : A collective term for server functions other than domain controller, such as file and printserver, on a Microsoft network.

Modem : A device for sending computer data over a voice phone line. Modem stands for modulate/demodulate.

Multi-Casting : Sending a message simultaneously to a select group of systems. Compare to broadcasting.

Name resolution : The process of converting a people-friendly alphanumeric system name or domain name intothe IP address recognized by the network.



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NetWare : A network server operating system from Novell.

Network : A system or group of interconnected elements. A computer network is a group of computers andperipherals connected together to communicate with each other and to share information and resources.

Network adapter card : A plug-in expansion card with a connection for a network cable, or an antenna for

wireless transmission. Also called a network interface card or NIC.

NIC : Network Interface Card. A plug-in expansion card with a connection for a network cable, or an antenna forwireless transmission. Also called a network adapter card.

node : Any point in a network that can influence the flow of data on that network. This usually refers to each of thesystems and peripherals on the network that have their own physical device address.

Novell : A software company that produces NetWare and other networking products.

NT : Windows NT, an operating system from Microsoft.

Offline : Not available to the network.

Online : Turned on and connected to the network.

Operating system : The master control program that runs the computer and allows it to execute applications.

OS X : The latest operating system for Macintosh computers, based on the Linux kernel but with a more user-friendly graphic interface. It includes networking capabilities.

Packet : A block of information configured for transmission over a network.

Password : A string of characters that a user must enter to gain access to a resource that is password-protected.

PC Anywhere : A common program used for control of a remote system.

Peer-to-peer : A small network where each computer has equal status and control. Compare to client-server.

Port : An address in memory used to transfer data into and out of a system. TCP/IP needs a port number to beable to provide the communication connection. RemoteScope allows configuring the Port number between10000~50000.

Protocol : An agreed-upon standard for how something will be done. Computer protocols are rules for theexchange of information.

Proxy server : A server that sits between a client and a web server and represents itself to each end as being theother. It can be used in two ways. For the web server it can cache frequently accessed pages to reduce the web-server's traffic. For security of the LAN clients it can present a single IP address to the Internet and prevent directaccess to the rest of the LAN.



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Remote Access Service : The protocol used in Windows NT and its successors to provide remote dial-in accessto a network running Windows NT or its successors. Abbreviated RAS.

Remote connection: The link between a modem and a network through a dial-up connection. Compare to thedirect connection made by a network card.

Repeater: A device to boost network signals transmitted over a long span.

RJ-11 : A four-wire jack used with Cat3 cable for telephone

RJ-45 : An eight-wire jack used with Cat5 cable and Ethernet cabling.

Rollout: Installing new software or updates to multiple systems in a network.

Router: An intelligent packet sorting device, used to route traffic on a network or between networks.

Sniffer: A utility program that captures packets going over a network.

SOHO network : Small Office / Home Office network, often peer-to-peer.

Static addressing: Assigning a specific IP address permanently to a specific system. Compare to dynamicaddressing.

Subnet: A LAN that is part of a larger logical network.

System administrator: A person who manages and maintains a network of computers or a large multi-usercomputer.

TCP/IP : A suite of communication protocols used on the Internet and other networks. It stands for TransmissionControl Protocol / Internet Protocol.

Template: A document or other file used as a standard to create other documents and files. The template willalready contain the properties and content that are common to those files created with the template so that theydo not have to be re-created or re-entered each time.

Throughput: A measure of the amount of data transferred in a specific amount of time, usually expressed as bitsper second (bps).

Tree: A way of organizing information in a hierarchy, with primary levels that have branches and sub-branchesunder them.

Tutorial videos: A collection of video clips on the RemoteScope CD that that give a visual presentation of themore common tasks. Highly recommended for new users.

UNIX : Any of a group of operating systems derived from an original program written at AT&T and licensed touniversities. The trademark to the name UNIX is owned by Novell, who sells a version called UnixWare.



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User: A person who requires a computer for the performance of a task or recreational activity. Also called an end-user.

User ID: The series of characters a system or network uses to distinguish one user from another. Also called auser name.

Virus: A program that cause damage either by deleting or corrupting files, or by interfering with computeroperations by reproducing itself to fill up disk or RAM space. Originally the term applied only to the reproducingkind but it has come to mean any deliberately harmful software.

Virtual Private Network : A secure connection created over a public network by using tunneling-modeencryption. Abbreviated VPN.

WAN: Wide Area Network. A connection between computers or networks located in separate cities or area codes.

Windows NT : The first full-featured network operating system from Microsoft, replaced by Windows 2000 but stillin widespread use.

Workgroup: A group of systems within a network that share specific resources.

WWW : The World Wide Web. That portion of the Internet that uses linking HTML pages.

Basic Tools for Networking

Crimping Tools UTP Cable RJ 45 Repeaters LAN Card

Bridge Switches Router Hub



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Coaxial Cable Cable Ties Screws Pliers

Multimeter Soldering Iron Desoldering Tool LAN Tester

Wireless Hub Bluetooth Device Telephone Cable Modem

Local Area Networking



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Data Communications

Data Communications

Is any system of computers, computer terminals or computer peripheral equipment used to

transmit/receive information between two or more locations

Data network

Access Point

Data Network Classifications

Local Area Networksex. Office Computer System

Metropolitan Area Networks

ex . Bank to bank computer access

Wide Area Networks

ex. Continental business access



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Global Area Networks

ex. Internet and Satellite Communications

Data Network Classifications

Local Area Networks

- A data networkcovering a relativelysmall geographical

area.

Metropolitan Area Networks

- A data networkdesigned for a town or city.In terms of geographic breadth,MANs are larger than local

area networks (LANs), butsmaller than wide-areanetworks (WANs).



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Wide Area Networks

- A data networks thatserve users across a broadgeographic area and oftenuses transmission devicesprovided by common carriers.

Global Area Networks

- A data networksdesigned to interconnectcomputer systems aroundthe entire globe.



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Networking Media

Copper Media

-Twisted Pair

ex. Unshielded Twisted Pair

Twisted Pair

ex. Shielded Twisted Pair

Coaxial Cable



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- Thinnet (RG-58) for - Thicknet (RG-8 or RG-11) 10Base2ethernet network 10Base5 ethernet network

RG-58 Cable RG-8 Cable

RG-11 Cable

Reason behind twisting

Cancellation

Differential signal generation



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Noise at random intervals of time

data

Receiving end

data

+3V

+3V

- 3V

Optical Media

- FiberOptic Cableex. Single Mode FOC

Most Commonly Used Medium In Local Area Networking



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Twisted Pair

- UTP Cat 5 and above

Now CAT 7 is ready for system upgrade

Unshielded Twisted Pair

The following summarizes the features of UTP Cable:

SPEED AND THROUGHPUT = 10 to 1000 Mbps

AVERAGE COST PER NODE = Least expensive

MEDIA AND CONNECTOR SIZE = Small

MAXIMUM CABLE LENGTH = 100 m

UTP Cabling Types

Cat 1 Used for telephone communication

Cat 2 Capable of transmitting data at speeds up to 4 Mbps

Cat 3 Used in 10BASET ethernet at speeds up to 10 Mbps

Cat 4 Used in Token Ring Networks at speeds up to 16 Mbps

Cat 5 Used in Fast ethernet at speeds up to 100 Mbps

Cat 5e Gigabit Ethernet speeds up to 1000 Mbps

Cat 6 Used in 10Gigabit Ethernet

Cat 7 Used in 10Gigabit Ethernet and above



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UTP Implementation

Cable Specification or Standards are set of rules or procedures that are widelyused and serve as the accepted method of performing a task.

A. TIA/EIA-568-A- This is a commercial building standard for telecommunications pathways and

spaces.

RJ45 connector

Types of UTP Network Cable

a. Straight-through cable a cable that maintains the pin connection.



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Applications of a straight-through cable

a. Switch to router

a. Switch to PC or server

a. Hub to PC or router

b. Crossover cable a cable that crosses the critical pair to properly align, transmit andreceive signals on the device with line connection.

Applications of a crossover cable

a. Switch to switch

b. Switch to hubc. Hub to hubd. Router to PCe. PC to PCf. Router to router

Pin Locations on RJ45 Connectors

TIA/EIA-568-A

Pin-outs1 = White Green

2 = Green3 = White Orange4 = Blue5 = White Blue


TIA/EIA-568-B

Pin-outs1 = White Orange

2 = Orange3 = White Green4 = Blue5 = White Blue6 = Green7 = White Brown8 = Brown


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6 = Orange7 = White Brown8 = Brown

Pin Outs on RJ45 Connectors

TIA/EIA-568-A

Pin-outs1 = White Green - - - - - - - - RD/TD +2 = Green - - - - - - - - - - - - - RD/TD -3 = White Orange - - - - - - - -TD/RD +4 = Blue5 = White Blue

6 = Orange - - - - - - - - - - - - TD/RD -7 = White Brown8 = Brown

RD RECEIVE SIGNAL

TD TRANSMIT SIGNAL

1 RD +

2 RD

3 TD +

4 NC

5 NC

6 TD -

7 NC

8 NC

1 TD +

2 TD

3 RD +

4 NC

5 NC

6 RD -

7 NC

8 NC

1 RD +

2 RD

3 TD +

4 NC

5 NC

6 TD -

7 NC

8 NC

1 TD +

2 TD

3 RD +

4 NC

5 NC

6 RD -

7 NC

8 NC

STRAIGHT-THROUGH CABLE CROSSOVER CABLE

Ethernet Standards for RJ45 Connector


Pin-outs1 = White Orange - - - - - - - - - RD/TD +2 = Orange - - - - - - - - - - - - - - RD/TD -3 = White Green - - - - - - - - - - -TD/RD +4 = Blue5 = White Blue

6 = Green - - - - - - - - - - - - - - - TD/RD -7 = White Brown8 = Brown

PINS 4,5,7,8 ARE HAVING NO CONNECTION


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Only Pairs 2 and 3 are used when having an Ethernet except Gigabit E

Networking Connectors

Copper Media Connectors

-Twisted Pair Cable Connectors and Jacks

ex. RJ45 male jack ex. RJ45 module female jack

Twisted Pair Connectors (communication cables, 25-pair cables)ex UY Connectors



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Coaxial Cable Connectors

Optical Media Connectors- Fiber Optic Cable ConnectorsST- Connector SC Connector


F type connector

T connector PL-259


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Sent : hi!

Received: hi!

Has a WLAN connection

Computer XWith a broadband connection

Computer H

- A structural guideline for information transfer- A great compatibility and interoperability among varioustypes of network technologies.

O S I LAYER MODEL

The Open Systems Interconnection Reference Model (OSI Model or OSI ReferenceModel for short) is a reference model provided vendors with a set of standardsthat ensured greater compatibility and interoperability among various types ofnetwork technologies that were produced by many companies around the world.

Is a primary model used as a guideline for network communications It defines the network functions that occur at each layer

It is a framework that facilitates an understanding of how information travelsthroughout a network.



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7 OSI Layer Models



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Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1

Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1

Computer A Computer X

For data to travel from the source to thedestination, each layer of the OSI model at

the source must communicate with its peer

layer at the destination

PHYSICAL LAYERLayer 1

- The Physical layerdefines all the electrical and

physical specifications fordevices. This includes thelayout of pins, voltages, andcable specifications.

DATA LINK LAYERLayer 2

- The Data Link layerprovides the functional andprocedural means to transfer

data between network entitiesand to detect and possiblycorrect errors that may occur inthe Physical layer.



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Network Layer

Layer 3

- The Network layer

provides the functional and

procedural means oftransferring variable length

data sequences from a

source to a destination via

one or more networks while

maintaining the quality of

service requested by the

Transport layer.

Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1

Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1







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Transport LayerLayer 4

- The Transport layerprovides transparent transferof data between end users,thus relieving the upper layersfrom any concern whileproviding reliable and cost-effective data transfer.

Session LayerLayer 5

- The Session layercontrols the dialogues(sessions) betweencomputers. It establishes,

manages and terminates theconnections between thelocal and remote application.

Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1

Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1



the source must communicate with its peerlayer at the destination



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Presentation Layer

Layer 6

- Ensures the information

that the application layer of

one system sends out can beread by the application layer

of another system.

Application Layer

Layer 7

- The Application

layer is closest to the end

user. It provides a means for

the user to access informationon the network through an

application.

Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1

Layer 7

Layer 6

Layer 5

Layer 4

Layer 3

Layer 2

Layer 1


For data to travel from the source to the

destination, each layer of the OSI model at



Networking Devices

Repeaters

- a device that simply regenerate or amplify the network signals at the bit level.- Layer 1 of the OSI model dependent



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Hub- a common connection point of the network and simply act as a repeater.- multiport repeater device Layer 1 dependent

Network Interface Cards

-An expansion board you insert into a computer so the computer can beconnected to a network.

- Layer 2 device because it carries a unique physical address called MediaAccess Control address.



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LAN 1

LAN 2

LAN 3

A W DF

A

W

F

D Q M K B

Q

M

K

B

Q

M

K

B

S P O N

S

P

O

N

MAC address table

MAC address = S, P , O , N

MAC address = Q, M , K , B

MAC address = A, W , F , D

Bridge- A device use to create 2 or more LAN segments, each of which is a separatecollision domain.- Filters network traffic by simply seeing the MAC address. A layer 2device

Switches-Are data link layer devices that let multiple LAN segments be interconnectedinto single networks. A layer 2device same as bridge.



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Unit of Competency Configure Computer Systems and Networks ELC724320 CN 25

Module Title Configuring Computer Systems and Networks Page 38 of 42

Router- is an internetworking device that passes data packets between networks basedon Layer 3 addresses.- makes decisions regarding the best path for delivery of data on the network.

Network Topologies

(Most common topologies)

STAR a multipoint data network where stations are connected by a cable directly to acentral common concentration point.

BUS multipoint data network that makes it relatively simple to control data flowbetween and among the computers because this configuration allows all station toreceive every transmission over the network



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D F

X V

RING multipoint data network where all the stations are connected in series to form aclose loop circle.

Computer E

Computer xComputer Z

Transmission is UNIDIRECTIONAL

Each device waits for its

turn to send

LAN Transmission FormatsTRANSMISSION IS SIMPLY A DATA TRANSFER

Baseband Technology

-A type of data transmission in which digital or analog data is sent over a singleunmultiplexed channel, such as an EthernetLAN. Baseband transmission use TDM to sendsimultaneous bits of data along the full bandwidth of the transmission channel.

Broadband Technology

- Broadband transmission formats use the connecting media as a multichannel devicewith each channel occupies a different frequency band within the total allocated bandwidth.



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Workstation and Server Relationships

Peer-to-peer network (workgroup PC)

- a networked computer that acts as equal partners, or peers, to eachother.- Each computer with in the network can take on the client function orthe server function.

Computer A Computer B

At one time:

Requests a print

At another time:

Requests a file

Client-Server Network- In a client-server arrangement, network services are located on adedicated computer called a server, which responds to the requestof clients.

workstations server

File

Print

internet

GLOSSARY

ACCESS POINT - In a wireless local area network (WLAN), an access point is a stationthat transmits and receives data (sometimes referred to as a transceiver).

BANDWIDTH The total allowable information that can pass through the medium.

BITS - A bit (short for binary digit) is the smallest unit of data in a computer.

COAXIAL CABLE - A type of wire that consists of a center wire surrounded byinsulation and then a grounded shield of braided wire. The shield minimizes electricaland radio frequency interference.

DIFFERENTIAL SIGNAL A signal that is only its mirror image of each other.



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ETHERNET A common LAN specification or standard for designing orimplementation.

FDM - Frequency-division multiplexing (FDM) is a scheme in which numerous signalsare combined for transmission on a single communications line or channel. Each signalis assigned a different frequency (subchannel) within the main channel.

FIBER OPTIC CABLE - A technology that uses glass (or plastic) threads (fibers) totransmit data. A fiber optic cable consists of a bundle of glass threads, each of which iscapable of transmitting messages modulated onto light waves.

FRAMES - In telecommunications, a frame is data that is transmitted between networkpoints as a unit complete with addressing and necessary protocol control information.

INTEROPERABILITY The ability of software/hardware in different machines fromdifferent vendors to share data.

MAC ADDRESS - In a local area network (LAN) or other network, the MAC (MediaAccess Control) address is your computer's unique hardware number. (On an EthernetLAN, it's the same as your Ethernet address.)

MAGNETIC FIELD A field that is generated when electric charge carriers such as

electrons move through space or within an electrical conductor. MEDIA/MEDIUM Any matter that is used to have a data transfer from one point to

another.

MULTI-MODE FIBER CABLE A fiber cable allows multiple paths of light to propagatethrough the fiber optic core.

MULTIPLEX - Multiplexing is sending multiple signals or streams of information on acarrier at the same time in the form of a single, complex signal and then recovering theseparate signals at the receiving end.

NOISE Unwanted signal present in the information signal

PACKETS - A packet is the unit of data that is routed between an origin and adestination on the Internet or any other packet-switched network.

RJ-45 A registered jack is a physical interface often used for terminating twisted pairtype cables.

SC CONNECTOR - A fiber-optic cable connector that uses a push-pull latchingmechanism similar to common audio and video cables. For multimode fiber.

SINGLE-MODE FIBER CABLE Uses only one mode of light to propagate through thefiber optic core.

ST CONNECTOR - A fiber-optic cable connector that uses a bayonet plug and socket. Itwas the first de facto standard connector for most commercial wiring. For Single-modefiber

TDM - Time-division multiplexing (TDM) is a method of putting multiple data streams in

a single signal by separating the signal into many segments, each having a very shortduration. Each individual data stream is reassembled at the receiving end based on thetiming.

THROUGHPUT The actual received information of the medium in a given time.



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TIA/EIA Telecommunications Industry Association/Electronics Industry Association

TWISTED PAIR CABLE - A type of cable that consists of two independently insulatedwires twisted around one another. The use of two wires twisted together helps to reducecrosstalk and electromagnetic induction.

ICT Department

III - Configure Computer Systems and Networks

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