Computer Networking - Elements and Components

When studying computer networks, one must consider the main elements that will compromise the computer network. The main elements that must be considered will be presented below:

1. Message: the message is a generic term that scribes the data to be transmitted. It can be email, webpage, user call, instant message, or any other forms. The message is generated by the end user that needs to make the transmission. This message will be fed to the network later.

Generally, the message is generated using software installed on computer. For example, if the message is email, it will be generated by email programs such as outlook. Also if the message is a web page request, it will be generated by a browser such as internet explorer. It can also be generated by a chatting program is it represents a call by the user.

Computer Networking - Elements and Components

2. Medium: the medium is the transmission path over which the data will be transmitted. Is is used to connect the end user with the network device or to connect the network devices with each other.

Many types exist for the medium. Mainly it can be wired or wireless medium. The wired medium can be copper or optical fibers. The copper is subdivided into coaxial cables and twisted pairs. The copper wires carry data as electrical pulses while the optical fiber carry data as light pulses. The wireless medium carries data as electromagnetic waves. Each of the above mediums has its own specifications and used according to the application.

3. Devices: there are two basic types of devices in the network: end user devices and network devices. The end user device is considered to be the source of the message. It can be a client computer or an IP phone. The function of the end user device is to send the data to the network.

On the other hand, the network devices are used along with the medium to forward the data generated by the end user device. They are located in between the end user devices and connected between them through the cables.

The main function of the computer network devices is to forward the data to the correct destination based on the address that is send along with the data. The two main devices that accomplish this are the routers and the switches. The router forwards the data according to the IP address while the switch forwards the data according to the MAC address inside the data frame.

4. Rules: the rules are the protocols that used between the end user devices that organize the communication. The two popular protocols are the IP protocol and the TCP protocol. When the end user needs to send the data, it runs a conversation first with the other device according to a set of rules that prepares for the transmission. Each network uses its own protocols set up by the administrator of the network to manage the operations inside the network. Note that this element is a software element and is set up by software programs

Computer Networking - Elements and Components
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Youssef Edward is an Electrical Engineer and he is the owner of tips-made-easy.info site where thousands of computer and network tips can be found. He studied too much in many branches of computer science. Click below to learn much more about computer networks

Computer Networking Connectivity.

Computer Network Devices overview.

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Wireless Networking - Router Vs Access Point

While planning for your wireless network you might be asking what is the difference between a router and an access point. You need to think of a router as more of a server because it performs many functions like a server. An access point only provides a portal for wireless client to connect to your existing LAN.

Routers can perform many functions. Routers can connect many different WLANs together acting like a traffic cop. Routers also act as a DHCP server. A DHCP server assigns dynamic IP address to your computer every time your computer starts up. If you don't have a DHCP server then you will have to assign each computer on your network a permanent IP address.

As I have said before your router can also act like a traffic cop. You can use a router to perform port forwarding to certain computers on your LAN. For example you can direct all internet traffic looking for your game server's port number to a specific computer on your LAN.

Wireless Networking - Router Vs Access Point

The ability to connect multiple computers to the internet is one of the main features of a router. The router is assigned one WAN IP address from your ISP. This IP address is called a public IP address that everyone on the internet can see. Because you have multiple computers connected to your router the router uses a protocol called NAT Network address translation NAT will assign the computers that are behind your routers IP address, private IP addresses. NAT acts as a firewall because computers on the internet cannot in theory even see your computers. They will only see the IP address of your router. NAT does block traffic from reaching your computers but it will not block Trojans from going out to the internet. That is why I do recommend installing a firewall on your LAN computers.

The role of an access point on a LAN is to give the wireless user a door way to enter. The more people that enter the door at the same time the slower they will go. 802.11b access points say they will give you a through put rate of 11mps but the actual rate is around 5MPS. 802.11g has a rating of 54mbps with an actual through put of 20mbps. The access points do have most of the same security features as a router such as WEP, WPA, 8021x and TKPI but they will not have the traffic cop functions like a router. Also the access points will not have NAT which would add an unnecessary layer to your network. To keep it simple access points just simulate plugging in your laptop to a port in the wall and that's it.A router is used on the border of you network to act as a traffic cop deciding who can come in and blocking those you want to keep out.

Wireless Networking - Router Vs Access Point
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Eric "The Wireless Ninja" Meyer is an expert in Wireless Networking. You can view other Wireless Networking articles at http://www.wirelessninja.com

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How to Trace a Cell Phone Location

New advances in technology have made it possible for anybody to trace a cell phone location.

These advances in technology designed to trace a cell phone location came about as a result of a number of recent events, including the events of September 11, 2001. Technological breakthroughs which have occurred since then include the inclusion of GPS technology in most mobile phones, and an improved ability to detect a phone's location based on signals from local transmission towers.

There are number services on the Internet which allow you to trace the location of a cell phone. They may differ in therms of interface and appearance, butthey are using the same data from the telecom companies.

How to Trace a Cell Phone Location

In the past the only way to gain access to the technology to trace a cell phone location was to buy equipment, and the use of this equipment was largely regulated to official organisations such as the police.

The way these services work is by gathering information from the telecom company that provides the cell phone service. this information includes the location of the cell phone as calculated by a combination of factors including the GPS as previously mentioned, and the distance to each of the nearest cellphone transmission masts. This is the same information which the police get.

There are wide range of reasons why you might want to trace a cell phone location, such as trying to find out where a friend or relative rates while you're out and about, keeping track of the location of a child, meeting up with friends, and trying to find shops and restaurants near you. Companies make use of these services in order to track their employees location, and also to provide security for employees when they are working in a remote location on their own. In the end, there are probably as many reasons as there are users.

The way GPS technology works in modern cell phones varies between the different cellphone networks, and with some operators it does not continuously transmit location. This means that when you want to trace a cell phone location, the information that you will be gathering is most likely collected from transmission tower locations.

The location of the phone will be tracked using triangulation - by taking 2 or more readings, it is possible to calculate where the signal is coming from by working out the triangle that fits the signal strengths. The 3rd point is the location of the phone.

However, when the person who has the phone has made an emergency call, this GPS transmission will always be sent. This is designed to ensure that the police can always track a cell phone location, in order to get help to people who need it.

The result of this design that the accuracy of the location which is provided by the service will be greater in areas which are more populated, and have more radio transmission masts, and will be lower in areas where there are very few radio masts, such is the wastelands, deserts, or un-populated areas of countryside. So, it is easier to track a cell phone location with a high level of accuracy in built up areas.

Nonetheless, most times you trace a cell phone location the information from the cell phone masts should be fine. After all, you do not need to know the person's location with a very great deal of accuracy for most purposes.

How to Trace a Cell Phone Location
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Matthew Burns is the author of Internet Guider. He has published a guide to cell phone search resources to help you locate cell phone numbers on the Internet.

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Wireless Network Components - Basics of Any Wireless Network

Client Software and Adapter

Any client computer, laptop or wireless device with a compatible wireless client adapter allows connectivity with an access point. The client adapter is a radio transmitter with firmware that supports any of 802.11a/b/g signaling. That is needed before the device can associate and authenticate with the access point. Some access points have a no client mode that doesn't allow any association from clients extending network distance. Client wireless software included with the adapter must be implemented with specific Windows platforms. The client adapter will be integrated with the laptop, PCMCIA slot or desktop PCI bus slot. They will support specific wireless standards, antenna characteristics, WiFi certification, WDS, network range and security. The wireless manufacturer software must be implemented for all available features. The following is a list of some client adapter configured settings.

Access Point (AP)

Wireless Network Components - Basics of Any Wireless Network

As the name suggests an AP (access point) allows connectivity between the wireless client or wireless device and the wired network. The AP takes wireless data packets from a client and translates them to standard Ethernet data frames before transmitting across the wired network. Standard category 5 twisted pair cabling will connect the AP point Ethernet port with a catalyst switch Ethernet port. The maximum distance between access point and network switch is 100 meters standard with Ethernet design.

WLAN Controllers

Wireless designs with hundreds of root APs on an enterprise network will sometimes deploy wireless LAN controllers. The design specifies lightweight APs connecting to a network switch. The 4404 WLAN controller device acts as a hub connecting 4 network switches supporting 100 access points. Cisco wireless control system (WCS) wireless network management software is sometimes deployed with WLAN controller design for planning, configuring and optimizing the network.

Power Injector

Cisco access points have a variety of power options such as AC adapters, power over Ethernet and power injectors. The placement of APs is such that in some situations an AC power outlet isn't available. Should your Ethernet switch not support power over Ethernet, an option such as power injectors extends the distance from an AC outlet. Distances of 1.24 miles are available with a fiber optic media converter.

Power over Ethernet

Cisco access points can be deployed with power over Ethernet (PoE) should the network switch modules support that feature. The distance of 300 feet is the same with Cisco prestandard and 802.3af. The Cisco prestandard use Cat 5 cabling pins 1, 2, 3, 6 for powering devices while 802.3af uses 1, 2, 3, 6 with 10/100/1000BaseT signaling and 4, 5, 7, 8 with 10/100BaseT. Select a network switch module with the power over Ethernet standard your AP has implemented and has a power wattage rating per port for your specific devices. The network switch power supply should be upgraded to support additional power draw from multiple devices. Deploying power over Ethernet will decrease implementation costs with deployment of IPT, wireless and Gigabit. See network switch documents at Cisco web site for information on what network switching modules support PoE and wattage ratings. 802.3af defines powered device class 2 at 3.84W - 6.49W and class 3 at 6.49W - 12.95W.

Power Patch Panel

Cisco inline power patch panels can be deployed where Ethernet switches don't support power over Ethernet and power injectors aren't an option. The patch panel does no switching. It powers the devices through a Cat 5 cable that is a maximum 300 feet at a specific rated wattage per port. The patch panel connects the access point to the wired switch with a patch cable.

Wireless Network Components - Basics of Any Wireless Network
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Shaun Hummel is the author of Cisco Wireless Network Design Guide and CiscoDesignBooks.com featuring Networking Books, eBooks, Certifications, Design Tools and Articles

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What Makes A Good Friend?

Good friendship counts!

Being a good friend is not just about having a good time with others, it's also about how willing you are to put your friends first or point out when they're doing something you don't agree with. Have a read through the following checklist and see how good a friend you really are.

Are you a good listener?

What Makes A Good Friend?

Part of being a good friend is about being willing to listen rather than just talk. This takes time and effort but if you can make time just to listen to others and respect what they have to say, then it's a sign of a good friend.

Are you approachable?

Do your friends often turn to you first to share a problem or seek help? Are you willing to make yourself available to friends at short notice and welcome them if they turn up at your door?

Are you trustworthy?

If a friend tells you something personal are you good at keeping it in confidence, or do you go and tell everyone at the first opportunity? People need to know that they can trust a friends with important information and you will only store up trouble for yourself if you are seen as unreliable. A good friend is both trustworthy and reliable.

Do you avoid gossiping about others?

This is one of the biggest signs of a good friend and really does stand out. Do you avoid speaking badly about others or spreading rumors in order to hurt them? Do you defend friends when you hear others gossiping about them? If you avoid gossiping others will notice how different you are and soon realize what a truly good friend you are.

Are you selfless rather than selfish?

Do you put your friends needs above your own? Do you try to find a compromise if you can't agree with a friend? Are you willing to do something your friend wants to do for a change rather than forcing them to do what you want? If you are willing to put your friends first in most things then this is a sign of a good friend.

Can you sensitively tell a friend what you really think?

Good friends don't just go with the flow, sometimes they have to be honest and tell someone what they really think. Sometimes your friends might want to do something that is morally wrong or illegal or just plain unfair on another person. Are you able to tell your friend honestly what you think about it, without just going along with it? The sign of a good friendship is when you can be totally honest with the other person, without them being offended because they know you have their best interests at heart.

What Makes A Good Friend?
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This was written by J Dawkins who created Friends and Money in March 2007. His site is dedicated to providing reviews of paid survey, social networking, and cash back shopping communities.

His aim is encourage visitors to Make Friends, Earn Money online.

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