Assignment Lanka

Star Topology

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:17:44 PST

Computers in a star topology are connected by cables to a hub. In this topology management of the network is made much easier (such as adding and removing devices), because of the central point. However because it is centralized more cable is required.

Because most star topologies use twisted-pair cables, the initial installation of star networks is also easier.
If one computer fails the network will continue to function, but if a hub fails all computers connected to it will also be affected. Star topologies are, or are becoming the topology of choice for networks.

Advantages:

Cheaper than a mesh. (less cable, less hardware per node)

Single links make the network easier to reconfigure.

Low cable housing requirements

Robustness. If one link is damaged the rest of the network can still function.

Easy fault identification and isolation.

Relatively low link traffic between hub and node compared to some other topologies.

Disadvantage:

Cabling still excessive compared to some other topologies as everything must be linked to the one central hub.

Wireless horizontal

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:15:58 PST

The horizontal market is characterised by the use of standard applications. The wireless network offers a standard protocol interface, for example TCP/IP. This means that users can buy off-the-shelf software, plug in their wireless modems and go. Because the network offers a standard interface, the software does not need to be specifically developed for the wireless network. This opens up a much broader market, as users are no longer constrained by the availability of specialist applications, so e-mail, database access, two-way paging and web browsing are all easily available.

In this picture, point-of-sales is shown as being a part of the horizontal market. In actuality point-of-sale lies in a a grey area, as it relies on a series of standard and non-standard protocols.

WDCS

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:17:30 PST

There are lots of different wireless data communication systems. To help us understand them all we divide them into different categories, Local Area Networks, Metropolitan Area
Networks and Wide Area Networks. Some of the techniques used for wireless LANs and MANs are shown here, but we'll discuss those in a little more detail in the next slide.

Wide Area Networks have been divided up into two distinct groups here circuit switched and packet switched. On the circuit switched side are Satellite phones, the American mobile telephone standard AMPS, GSM and PDC. HSCSD is a new data oriented circuit switched service for GSM.

The oldest of the packet switched services is Mobitex; a dedicated packet switched network
that has been available since 1986.

The other three systems are conceptually very similar, they all build on existing circuit switched mobile telephony infrastructures and they all add a packet switched service. GPRS provides packet data services by building on the GSM infrastructure, PPDC provides packet data services by building on PDC and CDPD provides packet data services by building on the AMPS system.

Packet Circuit Switched

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:16:11 PST

It is extremely important to understand the difference between packet switched and circuit
switched systems, a difference, which is illustrated here.

You can compare a circuit switched data to a train and the physical medium is the train line.
Before the train (data) can use the line it has to ask and be granted access. Once this is done
the train can then proceed on the line, but it has exclusive access to the line. No other trains can use the line while our train is there. In a data communications environment,
circuit switchings main drawbacks are the call setup overhead (that is, asking for and being
granted access to the line) and the low utilization of the physical medium (only one train at a time). One advantage of circuit switching is that the call setup procedure allows users to be allocated and guaranteed a certain bandwidth. A good example of circuit switching is the analogue telephone network. Before you can talk to anyone you have to dial their number (a call request). The call is physically switched through the network until you had an end-toend circuit between your telephone and the telephone you are calling. Only when the phone is answered at the other end (a call accept) can communication begin.

What about packet switching? Well, in this case our data can be imagined as cars and the physical medium as a motorway.

Instead of sending one big chunk of data, like we did with a circuit switched train, we send smaller chunks of data, with many users on the same channel simultaneously. The advantage with this is that we don't need any call set-up procedure, we just jump in the car and go. Packet switching also gives a much higher channel utilization, because many people can use the same motorway simultaneously.

The disadvantage is that because we have no way of knowing how much data other users are
going to send there is no guarantee of bandwidth if too many people try to use the motorway at the same time it will slow down and eventually stop. The best example of a packet switched network is the global Internet.

Wireless and Mobile

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:15:00 PST

Many people use the terms wireless and mobile as synonyms. This is not strictly true. In this table we try to illustrate the differences between the terms wireless and mobile.

Those users that are not wireless and not mobile are easy to come up with. This is what youcan call "traditional data communications" and consists of conventional LAN, MAN and WAN technology, such as ethernet, FDDI or X.25.

At the other extreme, there are users that are both wireless and mobile. So here we can have
taxis using radio modems, field service engineers (recall that Mobitex's first application was for Telia's field service engineers), transport and public safety users.

What about the users that are using wireless technology but are not mobile? These are the traditional "telemetry" applications that were mentioned in chapter 13. These include parking or gas meters and coke machines.

The last set of users, those that are mobile but not wireless are a little harder to define. Imagine the following scenario, I sit in my office in Gothenburg and work on my laptop PC connected to my local network. Then I pick up my laptop, jump on a plane and fly to Stockholm. There I plug my PC into the LAN in Stockholm and carry on working as if I was on my home network. In this case I'm using wired technology - the two Local Area Networks, but in some sense I'm mobile because I move around the country. This type of access is called Nomadic Computing. An example of technology that allows this kind of movement is Mobile IP, which will be explained in more detail later.

Connectivity

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:17:56 PST

In most cases a mobile node wishes to talk to some remote computer. For users and applications, the way these computers communicate doesn't matter that much. Using a wired
or wireless network makes no difference as long as the packets arrive. This is why these industry standard protocols, such as TCP and IP, are used. If the applications see some standard interface then they don't need to know if they are using a wireless network or a fixed network, they just see a standard interface. These standard interfaces are extremely important to both application and network designers.

Wifi with Windows XP

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:16:50 PST

Configuration -Wifi with Windows XP

If your computer is not currently connected to a wireless network, Windows may present the following message to let you know that it has detected one or more of them. Click on the Wireless networks detected balloon to display a list of available networks.

If your computer is already connected to a wireless network or does not present the above message, right-click on the Wireless Network Connection icon on the right of the Task Bar and then click on View Available Wireless Networks to display the list of available wireless networks.

From the Wireless Network Connection window, click on Change advanced settings under Related Tasks. Do not choose JMU-Official-Wireless from here the first time.

If you are logged in as a regular (non-Administrator) user, Windows will let you know that you cannot change some settings. Click on the OK button.

The Wireless Network Connection Properties window will come up on the General tab. Click on the Wireless Networks tab at the top.

Now click on the Add... button under Preferred networks. This will begin to configure Windows XP to join the wireless network and will need to be done only once.

In the resulting Wireless network properties window, enter JMU-Official- Wireless in the Network name (SSID) field.

Then select WPA2 from the Network Authentication drop-down list under Wireless network
key.

After selecting WPA2 from Network Authentication, the Data encryption will automatically be set to AES. Click on the Authentication tab at the top to continue.

Next, select Protected EAP (PEAP) from the EAP type drop-down list.

Then uncheck the box next to Authenticate as computer when computer information is available.

If your computer is NOT joined to Active Directory, click on Properties. If your computer IS joined to Active Directory, click on OK. Your computer will automatically sign in to the wireless network using the Active Directory credentials you used to log in to your computer. If you do not want it sign in automatically, click on Properties instead. If you aren’t sure whether your computer is joined to Active Directory, click on Properties.

If you clicked Properties, the Protected EAP Properties window will be displayed. From here, click the Configure button next to Secured password (EAP-MSCHAP v2).

If your computer is NOT joined to Active Directory, uncheck the box next to Automatically use my Windows logon name and password (and domain if any), then click on OK. If your computer IS joined to Active Directory and you want your computer to automatically sign in to the wireless network, leave the box checked and click on OK. If you are not sure if your computer is joined to Active Directory, uncheck the box and click on OK.

This will return you to the Protected EAP Properties window. Click on OK.

This will return you to the Wireless network properties window. Click on OK.

This will return you to the Wireless Network Connection Properties window and JMU-Official-Wireless will now be listed under Preferred networks. If you clicked OK instead of Properties after choosing PEAP from the EAP type drop-down list, you will return here. Click on OK.

Windows now will attempt to connect to the JMU-Official-Wireless network if it is in range. If your computer is not joined to Active Directory (or if you unchecked the Automatically use my Windows logon name and password setting), you will receive a message asking for your logon credentials to connect to the wireless network. Click on the Wireless Network Connection balloon to bring up the login prompt.

Enter your e-ID and password, then click OK. Be sure to leave Logon domain empty.

Windows will then attempt to validate the authentication server’s certificate. Click on the Wireless Network Connection balloon to continue.

You will then be prompted to accept the authentication server’s certificate to initiate encryption. This keeps your e-ID and password safe. To accept the certificate, whose Root Certification Authority will be Thawte Premium Server CA, click on OK.

If your computer is joined to Active Directory, Windows will use the domain credentials you logged on with to join the JMU-Official-Wireless network. It may take several seconds for your computer to acquire an IP address, during which time Windows may change the Wireless Network Connection icon to look like the one below on the far left.

After successfully connecting to the wireless network and getting an IP address, Windows will display the following message (though your Signal Strength may vary).

Reconnecting

If your computer is not currently connected to a wireless network, Windows may present the following message to let you know that it has detected one or more of them. Click on the Wireless networks detected balloon to display a list of available networks.

If your computer is already connected to a wireless network or does not present the above message, right-click on the Wireless Network Connection icon on the right of the Task Bar and then click on View Available Wireless Networks to bring up the list of available wireless networks.

From the Wireless Network Connection window, click on JMU-Official- Wireless, which will highlight it, and then click the Connect button at the bottom

Windows will present a progress display while it attempts to connect to the wireless network.

It may take several seconds for your computer to acquire an IP address, during which time the progress display message may change from Waiting for the network... to Waiting for network to be ready....

After Windows has successfully reconnected to the wireless network it will return to the Choose a wireless network window, showing JMU-Official-Wireless as Connected. Click on the red X button in the top right corner to finish.

Now you have connected Wifi " With Best Regards, Assignment Lanka"

Spyware

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:17:02 PST

Spyware is any application that collects information about your computer activities and then sends that information to another individual or company without your knowledge or permission. Spyware often arrives bundled with freeware (free) or shareware (trial) programs, through email or instant messenger, as an Active X install, or by someone with access to your computer. Once on your drive, spyware secretly installs itself and goes to work. Spyware can be difficult to detect, and difficult (if not impossible) for the average user to remove.

Spyware can:

Track your online surfing habits, profile your shopping preferences, gather personal
information (age, sex, etc, possibly credit card info, PIN numbers)
Send your email address to the company/person that made the spyware; that
company/person can now send spam to your email account.
Decrease your connection speed/hog your internet connection by sending information
about you and your computer to the company/person that made the spyware
Hijack your web browser’s start page, bombard you with pop-up advertisement boxes
Run in the background and slow your computer down, alter important system files,
make your computer unstable and crash

Characteristics Wireless

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:14:47 PST

Because wireless data uses an unguided medium it suffers from certain problems that do not affect its wired counterpart. One must remember that a wireless user is constrained by the network coverage. If the user moves to an area without coverage, then the user's terminal becomes useless. Although network operators try to minimize these "blackspots" they are inevitable, especially for new networks that are in the process of being deployed.

Multi-path fading, log-normal fading, inter-symbol interference and attenuation are all characteristics of the radio medium. Coupled with the limited amount of frequency spectrum available to wireless applications these attributes mean that the raw bit error rate is greater
than that found in guided mediums. This means that greater overheads are required to maintain acceptable error rates, thus reducing the amount of user data that can be sent per second.

So, wireless systems almost always offer lower bit rates than their wired alternatives.

Wireless systems also tend to have a higher latency than wired systems. For most protocols this is not a big issue, but is something that should be addressed when setting protocol parameters (e.g., timeouts should generally be longer due to the slower response times).

Information threat

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:18:44 PST

The threat of information leaks

Organizations often fail to acknowledge that there is a great risk of crucial data being stolen from within the company. Various studies have shown how employees use email to send out confidential corporate information. Be it because they are disgruntled and revengeful, or because they fail to realize the potentially harmful impact of such a practice, employees use email to share sensitive data that was officially intended to remain in-house.

As the 2003 Hutton enquiry in the UK demonstrated, government officials and BBC executives were found to have used email to make disclosures that were confidential. A March 1999 PC Week article referred to a study where, out of the 800 workers surveyed, 21-31% admitted to emailing confidential information - like financial or product data - to recipients outside the company.

3G Access

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:15:12 PST

Currently, third-generation mobile wireless services (3G) are coming onto the market that will allow users access the Internet, transmit data and voice, and utilize various multimedia services at speeds of 2 mbps or higher.

3G technologies are turning telephones and other devices into multimedia players, making it possible to download music and video clips. The new service is called the freedom of mobile multimedia access (FOMA) and it uses wideband code division multiple access (W-CDMA) technology to transfer data over its networks. W-CDMA sends data in a digital format over a range of frequencies, which makes the data move faster (but also uses more bandwidth than digital voice services). W-CDMA is not the only 3G technology; competing technologies include CDMAOne, which differs technically but should provide similar services.

Wireless Fidelity

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:13:37 PST

Wireless broadband systems use radio signals to send and receive data and voice at speeds ranging from 128 kbps to 1.5 Mbps. However, speeds are increasing every day and many Wi-Fi systems can transmit at speedsfrom 1-12 Mbps. In general, wireless providers offer Internet access via ﬁxed wireless technology that relies on a stationary signal base. Wireless broadband services use the same radio frequency spectrum that supports pagers, cell phones, microwave signals and more.

With a ﬁ xed wireless system, the provider installs a small antenna (dish) at the user’s premises which is wired to a modem on the user’s computer. Radio waves sent from the user’s antenna to the provider’s antenna connect the computer to the Internet. For optimal usage, the user’s
antenna should have a clear line-of-sight to the wireless broadband provider’s antenna. Bad weather, rugged topography and line-of-sight obstructions can impede service.

tooth are not interoperable. Bluetooth is a computing and telecommunications industry speciﬁ cation that describes how mobile phones, computers and PDAs can easily interconnect with each other as well as telephones and computers using a wireless connection over very short distances. Bluetooth and Wi-Fi are different in a number of ways and should not be viewed as competitors. The biggest difference between the technologies is that Wi-Fi boasts faster data transfer speeds and range, making it a good replacement for Ethernet systems, while Bluetooth requires less power and is prominent in small systems such as personal digital assistants (PDAs).

Fiber To Home

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:15:26 PST

Fiber-To-The-Home (FTTH)

FTTH In an FTTH system, glass ﬁ ber cables go directly from the Internet backbone to the user’s premises, using high-speed pulses of light to transport information. Fiber-optic cables have large bandwidth (speeds greater than 2.5 gigabits per second).

More and more, both traditional phone companies and start-up companies are installing FTTH to deliver broadband services, particularly in areas with new residential and commercial construction. Companies with older copper networks are, in some cases, overlaying copper-wired networks with new FTTH systems, then removing the old networks. Two types of FTTHarchitectures are currently used: Pointto- point and passive optical network (PON).

Point-to-point providers install an optical transceiver in the provider’s central ofﬁ ce for each customer. Fiber-optic cable then connects the central ofﬁ ce to the customer’s premises, much like a telephone line. PON is a ﬁ ber optic network without active electronics, such as repeaters. A PON uses passive splitters to deliver signals to multiple terminal devices using a tree structure transmission network. PON systems use transceivers with splitters that may be located as far as 30,000 feet from the provider’s central ofﬁ ce. An optical electrical converter (OEC) installed on or near the customer’s property converts the optical signal to an electrical signal, allowing it to connect to the end user.

Bus Network

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:16:22 PST

A network layout where one trunk cable provides the main path of communications. Each node is then connected to this common cable. This common cable also known as “Backbone”

In this type of arrangement the ends of the cables must have terminators installed to complete the circuit and devises are attached to the Drop lines or taps. This type of topology is very poor at handling cable problems as all of the stations beyond the affected area will be brought down.

Advantages:

Ease of installation

Low cabling requirements

Disadvantages:

Difficult to reconfigure nodes.

Fault isolation is difficult.

Too many connections to the backbone can seriously degrade performance.

A fault in the bus cable causes the whole network to be disabled.

Broadband

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:15:45 PST

Deﬁne The term “broadband” generally refers tohigh-speed Internet connections transmitting data at speeds greater than 200 kilobytes per second (Kbps), compared to the 56 Kbps maximum speed offered by traditional dial-up connections. While traditional dial-up access (using normal voice telephone line technology) sufﬁ ces for many consumers, some need or want the
much faster connections that technological advances now allow.

This primer offers a brief description of each technology used to provide broadband services.

• Digital Subscriber Line (DSL)
• Coaxial Cable
• T-1 Lines
• Fiber-To-The-Home (FTTH)
• Wireless Fidelity (Wi-Fi)
• Satellite
• Broadband over Power Line (BPL)
• Broadband over Gas Line (BGL)

Benefits of Wireless

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:13:55 PST

Originally employed to free network elements to roam in manufacturing and warehouse facilities, wireless LANs (WLANs) are now deployed throughout the enterprise as a cost-saving measure. They can be used to replace wired LANs, or as an extension of a wired infrastructure.

It costs far less to deploy a wireless LAN than to deploy a wired version. The savings isn’t just in the falling cost of wireless components; it’s in the installation of the infrastructure as well. A major cost of installing and modifying a wired network is the expense to run network and power cables, all in accordance with local building codes. For this reason, WLANs are being installed even when the network is comprised only of non-roaming desktops. Examples of additional applications where the decision to deploy WLANs results in large cost savings include:

Additions, moves, and changes within an organization
Installation of temporary networks
Installation of hard-to-wire locations
Elimination of costly leased lines

Wireless LANs give the enterprise more mobility and flexibility by allowing workers to stay connected to the Internet and to the network as they roam from one coverage area to another. This increases efficiency by allowing data to be entered and accessed on site.

Besides being very simple to install, WLANs are easy to understand and use. With few exceptions, everything to do with wired LANs also applies to wireless LANs. They function like, and are commonly connected to, wired Ethernet networks. They not only free the networked laptop to roam, but dramatically simplify and lower the cost of network deployment.

WiFi Network

noreply@blogger.com (Assignment Lanka) — Thu, 06 Jan 2011 02:14:09 PST

Each component of a WLAN requires a radio transceiver and antenna. Components are either stations or access points. Stations (STAs) are wireless LAN client radios. They can be incorporated into a LAN card installed in a desktop, a USB adapter, a PCMCIA or PC card, or can be integrated into the notebook or handheld device itself. Access Points (APs) form a bridge between wireless and wired LANs.

A Basic Service Set (BSS) is formed when two or more stations have recognized each other and established a network. The network can be configured in two basic ways:

Peer-to-peer (ad hoc mode) – This configuration is identical to its wired counterpart, except without the wires. Two or more STAs can talk to each other without an AP. When two or more stations form an ad hoc network, this is referred to as an Independent Basic Service Set (IBSS).
Client/Server (infrastructure networking) – This configuration consists of multiple stations connected to an AP, which acts as a bridge to a wired network. A BSS in this configuration is referred to as being in infrastructure mode.

An Extended Service Set (ESS) is formed when multiple overlapping BSSs (each containing an AP) are connected together by means of a distribution system, usually a wired Ethernet LAN. BSSs whose ranges overlap must transmit on different channels to avoid interference.

Range between STAs and APs is up to 100 m (depending on data rate), but the overall range of an ESS is limited only by the range of the wired distribution system. Also, ESSs can be further extended with wireless links up to several miles by the use of directional range extender antennas.

Introduction to Microsoft 2007 Office

noreply@blogger.com (Assignment Lanka) — Tue, 11 Jan 2011 01:30:00 PST

Introduction

If you have 2007 Office installed on your computer here are a couple of hints on how we’ll proceed.

To open an application, Double click quickly on the application icon (Word, PowerPoint, Excel, etc.) on the Windows desktop. Or, click the Start button, in the lower left corner of the screen, then click All Programs, move the cursor over Microsoft Office and select the application you wish

In this lesson, when we point out that you need to click a mouse button, it will signify to click the left mouse button – if not we indicate that you should click the right mouse button. So, forever move the arrow over the “place” we point out and “click left” unless we tell you otherwise.

The Microsoft Office Button

The first thing you’ll become aware of, when you open a 2007 Office application is that there is no longer a File choice in the Menu Bar. The arrow above points to the Microsoft Office Button – which replaces File.

As you move your cursor over the Microsoft Office Button a preview image (image on right) will appear.

Click the Microsoft Office button.

At what time you click the Microsoft Office button, it will turn orange and a “File like” menu will appear (similar to the image).

You’ll see that you now have little images for choices and that some of them have little arrows pointing to the right. These arrows indicate that there are extra choices for a selection.

We’ll explain you one of these on the next page.

On the right side of the Microsoft Office Button menu screen you will notice your most recently used files – Recent Documents (see arrow above).

Each Microsoft Office Button menu is tailored to its Office application

iphone wifi

noreply@blogger.com (Assignment Lanka) — Wed, 05 Jan 2011 04:09:27 PST

Wireless instructions for iPhone and iTouch setups

Make sure your device has an active connection to the internet.

1. Go to Settings

2. Select Wi-Fi

3. Choose Other…

4. The Name of the network..........

5. Security is WPA Enterprise

6. Your Username and Password

7. After you enter your Username and Password, select Join

8. It may take a moment, but your device should connect to the WIFI network *if* it is available in your location.

Network Manager

noreply@blogger.com (Assignment Lanka) — Wed, 05 Jan 2011 04:08:16 PST

Network management means different things to different people. In some cases, it involves a solitary network consultant monitoring network activity with an outdated protocol analyzer. In other cases, network management involves a distributed database, auto polling of network devices, and high-end workstations generating real-time graphical views of network topology changes and traffic. In general, network management is a service that employs a variety of tools, applications, and devices to assist human network managers in monitoring and maintaining networks.

Before or after implementing any Network It’s a duty for the Network Manager to handle it.The network manager is the person who takes decision regarding the network. This simple structure describes how the Network Manager’s authority dissolves among the subordinates It’s the duty of the Subordinate’s to report about various factors to the network manager. Also it’s the duty of the Network Manager to Report several things to the top management or to the chairmen. As a head of a Network, the Network Manager has many tasks to do when performing his profession.

Following are some Duties or Responsibilities of a Network Manager.

Coordinating Administrators Work

All the Network, Database & System Administrators are subordinates of the Network Manager. Due to that the Network Manager will have to coordinate with them. The

network manager will have to get various documents/reports from the administrators as they monitor some areas of the whole network.

Reporting to the Top Management Regarding the Network

The Network has to Report about various aspects of the network. He will need to get periodical reports on various factors which keep the network on line for utilization.

The Main Duties of the Network Manager can be divided into five sub units.
• Fault Management
• Configuration Management
• Account Management
• Performance Management
• Security Management
• Other Management Areas
o Hardware Management
o Software Management

Route process

noreply@blogger.com (Assignment Lanka) — Wed, 05 Jan 2011 04:10:00 PST

Routing involves the following two key elements.

The host must know which router to use for a given destination; the router is determined by the default gateway. The default gateway is the IP address of the router on your local network; this router will route the packet to the destination network.

The router must know where to send the packet; the destination is determined by the router's routing information table.

CRASH FREE NETWORK

noreply@blogger.com (Assignment Lanka) — Wed, 05 Jan 2011 04:09:05 PST

We can make crash free network to solve the problems which I given below.
• Using data traffic management and high speed equipments for does the network well. Normally switches are providing data management facility to the network. And using Ethernet stranded we can performed high speed for the network it might be can protect data packets.

• Using high speed cable type and using multiple caballing. We can use twisted pair cable for solving this problem and using high speed Ethernet cables e.g.: CAT 5e, CAT 6 etc. And use multiple lines for the caballing. The major thing is we want use high band width cables; most successful method is using Fiber Optic Cable for doing network but its given extra cost for the networking.

• Using high speed NIC for the networking. Adapter card should be high speed adapter card
because transferring data speed should be protected and the capacity of the NIC should be incise.

• Reduce the range between the computes and using repeaters and routes for amplify the data.

Data packets are not energy full for travel very long distances among the computers. So before made the network we want to reduce the range or else using the amplifier equipments for between computers. Those equipments are routers and repeaters.

• Using different wise network topologies. Net work topology is the other reason for the network crashing. So we can produce different network topologies for same network environment to solve the network crashing.

Direct route

noreply@blogger.com (Assignment Lanka) — Wed, 05 Jan 2011 04:12:31 PST

If two computers on the same physical network need to communicate, the packets do not require a router. The computers are considered to be on the same local network. In an IEEE 802.3/ethernet TCP/IP network, the sending entity encapsulates the packet in an ethernet frame, binds the destination Internet address to an ethernet address, and transmits the resulting frame directly to its destination. This process is referred to as direct routing. The Address Resolution Protocol (ARP) is an example of a direct routing protocol.
The destination system is on the same physical network if the network portions of the source and destination addresses are the same.

Indirect routing

If two computers that are not on the same physical network need to communicate, they must send the IP packet to a router for delivery. They are located on remote networks. Whenever a router is involved in communication, the activity is considered indirect routing.

Direct routing

noreply@blogger.com (Assignment Lanka) — Wed, 05 Jan 2011 04:12:47 PST

Interactivity on the Web

noreply@blogger.com (sanju) — Wed, 05 Jan 2011 04:08:01 PST

Five years ago, the Web was very static. You could see text and graphics and you could click on links. Then other types of media started to appear; sound, animation, video and interactive applications. The interactivity was brought about by four different techniques. The first is the Plug-in technique. A plug-in is not a part of a browser. It is a separate program that is invoked by the browser when it encounters a file with a format that the plugin module can understand. There are hundreds of plug-ins on the Internet that you can download and install on your computer. Some of them cost money, but most of them are free.

The difficulty with plug-ins is that you have to find them, download them and install them. First you must find the right plug-in on the Internet. There are different plug-ins for different platforms, so you have to make sure that the plug-in that you want to download is the right one. Then you have to download the plug-in; a process that typically takes 10 to 20 minutes through a 28.8 kbps modem. The file you’ve downloaded is almost always archived and compressed, so you have to decompress and de-archive it. Then you have to install the plugin before you’re ready to use it.

There is another variant of the plug-in technique called a helper application. A helper application is exactly the same thing as a plug-in, that is a small program that is invoked by the browser. The only difference is that a plug-in shows its information within the window of the browser, while a helper applications shows its information in an external window.

The second technique is called CGI, which stands for Common Gateway Interface. One use is for entering data in a form on a web page and submitting it by clicking on a button. Another use is to sense where the user clicks on an active image area. There are many other ways to use CGI.

The third technique, called the Scripting Languages, involves extending the HTML code by using a programming language called a script language. The code of the scripting language is mixed with the HTML code. When you open an HTML page with a word processor you can actually see the code of the scripting language. The browser interprets the scripting language code in a similar way it interprets the HTML code. The most common scripting language is JavaScript.

The fourth technique is Java. This technique involves sending, not just the data from the server to the client, but also the program that will handle this data. In this way users don’t have to find, download and install plug-ins on their computers.