Wednesday, 1 June 2011

::::::::::::::::::::::To Get And Show The Ip Via Javascript:::::::::::::::::::::


To Get And Show The Ip Via Javascript


To show the ip via JavaScript




var ip= '<!--#echo var="REMOTE_ADDR"-->';
document.write("Your IP Address is :"+ip+" ");
________________________________________________________________________________
__________________
To show IP via ASP




request.ServerVariables("REMOTE_ADDR")
________________________________________________________________________________
__________________
TO SHOW IP VIA PHP


<?
$remote_address = getenv("REMOTE_ADDR");
echo "Your IP address is $remote_address.";
$browser_type = getenv("HTTP_USER_AGENT");
echo "You are using $browser_type.";
?>

::::::::::::::::::SECRET CODES for NOKIA:::::::::::::::::::::::::::::::::


With Nokia codes or Nokia secret codes you can access hidden features and gain information about your Nokia phone. Many of the Nokia codes are only normally used by Nokia engineers. Nokiainfo.net takes no responsibility for any data loss resulting in using these Nokia codes.

Nokia code Code function
*3370# This Nokia code activates Enhanced Full Rate Codec (EFR) - Your Nokia cell phone uses the best sound quality but talk time is reduced my approx. 5%
#3370# Deactivate Enhanced Full Rate Codec (EFR)
*#4720# Activate Half Rate Codec - Your phone uses a lower quality sound but you should gain approx 30% more Talk Time
*#4720# With this Nokia code you can deactivate the Half Rate Codec
*#0000# Displays your phones software version, 1st Line : Software Version, 2nd Line : Software Release Date, 3rd Line : Compression Type
*#9999# Phones software version if *#0000# does not work
*#06# For checking the International Mobile Equipment Identity (IMEI Number)
#pw+1234567890+1# Provider Lock Status. (use the "*" button to obtain the "p,w" and "+" symbols)
#pw+1234567890+2# Network Lock Status. (use the "*" button to obtain the "p,w" and "+" symbols)
#pw+1234567890+3# Country Lock Status. (use the "*" button to obtain the "p,w" and "+" symbols)
#pw+1234567890+4# SIM Card Lock Status. (use the "*" button to obtain the "p,w" and "+" symbols)
*#147# This lets you know who called you last (Only vodofone)
*#1471# Last call (Only vodofone)
*#21# This phone code allows you to check the number that "All Calls" are diverted to
*#2640# Displays phone security code in use
*#30# Lets you see the private number
*#43# Allows you to check the "Call Waiting" status of your cell phone.
*#61# Allows you to check the number that "On No Reply" calls are diverted to
*#62# Allows you to check the number that "Divert If Unreachable (no service)" calls are diverted to
*#67# Allows you to check the number that "On Busy Calls" are diverted to
*#67705646# Phone code that removes operator logo on 3310 & 3330
*#73# Reset phone timers and game scores
*#746025625# Displays the SIM Clock status, if your phone supports this power saving feature "SIM Clock Stop Allowed", it means you will get the best standby time possible
*#7760# Manufactures code
*#7780# Restore factory settings
*#8110# Software version for the nokia 8110
*#92702689# Displays - 1.Serial Number, 2.Date Made, 3.Purchase Date, 4.Date of last repair (0000 for no repairs), 5.Transfer User Data. To exit this mode you need to switch your phone off then on again
*#94870345123456789# Deactivate the PWM-Mem
**21*number# Turn on "All Calls" diverting to the phone number entered
**61*number# Turn on "No Reply" diverting to the phone number entered
**67*number# Turn on "On Busy" diverting to the phone number entered
12345 This is the default security code press and hold # Lets you switch between lines


--------------------

:::::::::How to Copy a Full DVD On 1 CD:::::::::::::::::::




Copy a full DVD movie on one disk
Posted by DoMiN8ToR on Monday 5 March 2001A BIGPLUTER FAQ

This FAQ will tell you how to copy a full DVD film onto one disk, with excellent video quality and sound. But before I get started you must have these programs in order to do it because without these you cannot do it cheaply, basically you would have to buy a dvd ripper and some very expensive disks.

Programs needed:
  • Dvd to Mpeg squeezer.
  • Panasonic Plugins.
  • Xing encoder and Xing player (Xing player optional as windows player can run them).
You will probably find them at DVDSoft.net

Once you have installed (here's help) all these programs correctly you have to apply the appropriate settings.
1.        Before you start the Dvd to Mpeg squeezer you have to initialize the encoder, then when the box appears you have to click on options.
2.        Click on the capture settings box.
3.        The frame rate must be 23.976fps.
4.        Maximum frame number must be set at 300,000.
5.        Leave a tick in the stop capturing by title change.
6.        Leaving a tick in add bands is optional as this is for the zoom function.
7.        No ticks in the other 2 boxes.
8.        Resize filter set to BiCubic filter.
9.        Interpolation mode set to No Interpolation.
10.     Then come out of that menu and go into MPV settings.
11.     This is the main part of the rip and you must get these settings exact or it will not fit on one disk.
12.     The Data Rate (kbits/sec) Video must be set to 600kbits/sec delete the number what's in and put that one in the Video. The Audio must read 224 and the System must say 824 and the Stream format must be MPEG1.
13.     Noise Reduction must be set to: Medium.
Video filter must be set to: Adaptive.
Level must be set to: Strongest.

Color tone optional but I set it to TV.

These are the settings for a full film rip and full match source taken from a Dvd.

This is the amount of film you can put on:
1. 650 meg disk equals to 106 minutes of
2. 700 meg disk equals to 116 minutes of film.

Now if a film is longer than 116 minutes you will have to encode the film at a lower meg rate. To do this you will have to encode the ripped Dvd down to an NTSC rip or even lower down to a PAL rip. This should put any film onto 1 disk then, but this will still be a very good quality. If you encode a film even lower than PAL say a 384k rip you could get up to 4 hours of film on 1 disk but the quality of the film degrades drastically but watch able from 7 feet away.

This FAQ was written by Bigpluter and can be modified only by someone who has got a littlepluter, but if you do let me know ok.

ONLY BIGPLUTER MAKES IT POSSIBLE.

Reaction by fzkuno on Tuesday 6 March 2001seen as how the goal is not to make a vcd compliant Mpeg stream, why not compress the audio further.. 112 kbit/s does the trick for me..
and why not use DivX instead.. mpeg 1 video is not necessarily the best format, because much of the computing power will go into the bicubic filtering necessary to downscale the video to a cif format in OK quality.

video:
640*320 (for widescreen)at 600kbit/s DivX lowmotion with a keyframe every 3 secs.
bilinear filtering.
and
Audio:
112 kbit/s mp3
and you're all set..I choose DivX low motion because of the nature of the films I usually back up, but fastmotion could be applied as well.

sure the quality of mpeg is good, because of the frequency of keyframes, (1/15 I think..) but the problem is the bicubic filtering, and the rescaling to 352*X
it's just not too cool..

theres a version of flaskmpeg out there with DeCss built in.. that means you can rip directly from the DVD instead of having to copy it to the HD.
FZ Kuno

:::::::::How to Copy a Full DVD On 1 CD:::::::::::::::::::




Copy a full DVD movie on one disk
Posted by DoMiN8ToR on Monday 5 March 2001A BIGPLUTER FAQ

This FAQ will tell you how to copy a full DVD film onto one disk, with excellent video quality and sound. But before I get started you must have these programs in order to do it because without these you cannot do it cheaply, basically you would have to buy a dvd ripper and some very expensive disks.

Programs needed:
  • Dvd to Mpeg squeezer.
  • Panasonic Plugins.
  • Xing encoder and Xing player (Xing player optional as windows player can run them).
You will probably find them at DVDSoft.net

Once you have installed (here's help) all these programs correctly you have to apply the appropriate settings.
1.        Before you start the Dvd to Mpeg squeezer you have to initialize the encoder, then when the box appears you have to click on options.
2.        Click on the capture settings box.
3.        The frame rate must be 23.976fps.
4.        Maximum frame number must be set at 300,000.
5.        Leave a tick in the stop capturing by title change.
6.        Leaving a tick in add bands is optional as this is for the zoom function.
7.        No ticks in the other 2 boxes.
8.        Resize filter set to BiCubic filter.
9.        Interpolation mode set to No Interpolation.
10.     Then come out of that menu and go into MPV settings.
11.     This is the main part of the rip and you must get these settings exact or it will not fit on one disk.
12.     The Data Rate (kbits/sec) Video must be set to 600kbits/sec delete the number what's in and put that one in the Video. The Audio must read 224 and the System must say 824 and the Stream format must be MPEG1.
13.     Noise Reduction must be set to: Medium.
Video filter must be set to: Adaptive.
Level must be set to: Strongest.

Color tone optional but I set it to TV.

These are the settings for a full film rip and full match source taken from a Dvd.

This is the amount of film you can put on:
1. 650 meg disk equals to 106 minutes of
2. 700 meg disk equals to 116 minutes of film.

Now if a film is longer than 116 minutes you will have to encode the film at a lower meg rate. To do this you will have to encode the ripped Dvd down to an NTSC rip or even lower down to a PAL rip. This should put any film onto 1 disk then, but this will still be a very good quality. If you encode a film even lower than PAL say a 384k rip you could get up to 4 hours of film on 1 disk but the quality of the film degrades drastically but watch able from 7 feet away.

This FAQ was written by Bigpluter and can be modified only by someone who has got a littlepluter, but if you do let me know ok.

ONLY BIGPLUTER MAKES IT POSSIBLE.

Reaction by fzkuno on Tuesday 6 March 2001seen as how the goal is not to make a vcd compliant Mpeg stream, why not compress the audio further.. 112 kbit/s does the trick for me..
and why not use DivX instead.. mpeg 1 video is not necessarily the best format, because much of the computing power will go into the bicubic filtering necessary to downscale the video to a cif format in OK quality.

video:
640*320 (for widescreen)at 600kbit/s DivX lowmotion with a keyframe every 3 secs.
bilinear filtering.
and
Audio:
112 kbit/s mp3
and you're all set..I choose DivX low motion because of the nature of the films I usually back up, but fastmotion could be applied as well.

sure the quality of mpeg is good, because of the frequency of keyframes, (1/15 I think..) but the problem is the bicubic filtering, and the rescaling to 352*X
it's just not too cool..

theres a version of flaskmpeg out there with DeCss built in.. that means you can rip directly from the DVD instead of having to copy it to the HD.
FZ Kuno

make a autorun file for CD??


If you wanna make a autorun file for that CD you are ready to burn just read this...

1) You open notepad

2) now you writ: [autorun]
OPEN=INSTALL\Setup_filename.EXE
ICON=INSTALL\Setup_filename.EXE

Now save it but not as a .txt file but as a .inf file.

But remember! The "Setup_filename.EXE" MUST be replaced with the name of the setup file. And you also need to rember that it is not all of the setup files there are called '.exe but some are called '.msi

3) Now burn your CD with the autorun .inf file included.

4) Now set the CD in you CD drive and wait for the autorun to begin or if nothing happens just double-click on the CD drive in "This Computer"

Monday, 2 May 2011

What is Network Cabling?


Cable is the medium through which information usually moves from one network device to another. There are several types of cable which are commonly used with LANs. In some cases, a network will utilize only one type of cable, other networks will use a variety of cable types. The type of cable chosen for a network is related to the network's topology, protocol, and size. Understanding the characteristics of different types of cable and how they relate to other aspects of a network is necessary for the development of a successful network.
The following sections discuss the types of cables used in networks and other related topics.

Unshielded Twisted Pair (UTP) Cable

Twisted pair cabling comes in two varieties: shielded and unshielded. Unshielded twisted pair (UTP) is the most popular and is generally the best option for school networks (See fig. 1).
                                                                                              Fig.1. Unshielded twisted pair
The quality of UTP may vary from telephone-grade wire to extremely high-speed cable. The cable has four pairs of wires inside the jacket. Each pair is twisted with a different number of twists per inch to help eliminate interference from adjacent pairs and other electrical devices. The tighter the twisting, the higher the supported transmission rate and the greater the cost per foot. The EIA/TIA (Electronic Industry Association/Telecommunication Industry Association) has established standards of UTP and rated five categories of wire.

Categories of Unshielded Twisted Pair

Type
Use
Category 1
Voice Only (Telephone Wire)
Category 2
Data to 4 Mbps (LocalTalk)
Category 3
Data to 10 Mbps (Ethernet)
Category 4
Data to 20 Mbps (16 Mbps Token Ring)
Category 5
Data to 100 Mbps (Fast Ethernet)

Buy the best cable you can afford; most schools purchase Category 3 or Category 5. If you are designing a 10 Mbps Ethernet network and are considering the cost savings of buying Category 3 wire instead of Category 5, remember that the Category 5 cable will provide more "room to grow" as transmission technologies increase. Both Category 3 and Category 5 UTP have a maximum segment length of 100 meters. In Florida, Category 5 cable is required for retrofit grants. 10BaseT refers to the specifications for unshielded twisted pair cable (Category 3, 4, or 5) carrying Ethernet signals. Category 6 is relatively new and is used for gigabit connections.

Unshielded Twisted Pair Connector

The standard connector for unshielded twisted pair cabling is an RJ-45 connector. This is a plastic connector that looks like a large telephone-style connector (See fig. 2). A slot allows the RJ-45 to be inserted only one way. RJ stands for Registered Jack, implying that the connector follows a standard borrowed from the telephone industry. This standard designates which wire goes with each pin inside the connector.

Fig. 2. RJ-45 connector

Shielded Twisted Pair (STP) Cable

A disadvantage of UTP is that it may be susceptible to radio and electrical frequency interference. Shielded twisted pair (STP) is suitable for environments with electrical interference; however, the extra shielding can make the cables quite bulky. Shielded twisted pair is often used on networks using Token Ring topology.

Coaxial Cable

Coaxial cabling has a single copper conductor at its center. A plastic layer provides insulation between the center conductor and a braided metal shield (See fig. 3). The metal shield helps to block any outside interference from fluorescent lights, motors, and other computers.


Fig. 3. Coaxial cable
Although coaxial cabling is difficult to install, it is highly resistant to signal interference. In addition, it can support greater cable lengths between network devices than twisted pair cable. The two types of coaxial cabling are thick coaxial and thin coaxial.
Thin coaxial cable is also referred to as thinnet. 10Base2 refers to the specifications for thin coaxial cable carrying Ethernet signals. The 2 refers to the approximate maximum segment length being 200 meters. In actual fact the maximum segment length is 185 meters. Thin coaxial cable is popular in school networks, especially linear bus networks.
Thick coaxial cable is also referred to as thicknet. 10Base5 refers to the specifications for thick coaxial cable carrying Ethernet signals. The 5 refers to the maximum segment length being 500 meters. Thick coaxial cable has an extra protective plastic cover that helps keep moisture away from the center conductor. This makes thick coaxial a great choice when running longer lengths in a linear bus network. One disadvantage of thick coaxial is that it does not bend easily and is difficult to install.

Coaxial Cable Connectors

The most common type of connector used with coaxial cables is the Bayone-Neill-Concelman (BNC) connector (See fig. 4). Different types of adapters are available for BNC connectors, including a T-connector, barrel connector, and terminator. Connectors on the cable are the weakest points in any network. To help avoid problems with your network, always use the BNC connectors that crimp, rather than screw, onto the cable.


Fig. 4. BNC connector

Fiber Optic Cable

Fiber optic cabling consists of a center glass core surrounded by several layers of protective materials (See fig. 5). It transmits light rather than electronic signals eliminating the problem of electrical interference. This makes it ideal for certain environments that contain a large amount of electrical interference. It has also made it the standard for connecting networks between buildings, due to its immunity to the effects of moisture and lighting.
Fiber optic cable has the ability to transmit signals over much longer distances than coaxial and twisted pair. It also has the capability to carry information at vastly greater speeds. This capacity broadens communication possibilities to include services such as video conferencing and interactive services. The cost of fiber optic cabling is comparable to copper cabling; however, it is more difficult to install and modify. 10BaseF refers to the specifications for fiber optic cable carrying Ethernet signals.


Fig.5. Fiber optic cable
Facts about fiber optic cables:
  • Outer insulating jacket is made of Teflon or PVC.
  • Kevlar fiber helps to strengthen the cable and prevent breakage.
  • A plastic coating is used to cushion the fiber center.
  • Center (core) is made of glass or plastic fibers.

Fiber Optic Connector

The most common connector used with fiber optic cable is an ST connector. It is barrel shaped, similar to a BNC connector. A newer connector, the SC, is becoming more popular. It has a squared face and is easier to connect in a confined space.

Ethernet Cable Summary

Specification
Cable Type
Maximum length
10BaseT
Unshielded Twisted Pair
100 meters
10Base2
Thin Coaxial
185 meters
10Base5
Thick Coaxial
500 meters
10BaseF
Fiber Optic
2000 meters
100BaseT
Unshielded Twisted Pair
100 meters
100BaseTX
Unshielded Twisted Pair
220 meters

Wireless LANs


Not all networks are connected with cabling; some networks are wireless. Wireless LANs use high frequency radio signals, infrared light beams, or lasers to communicate between the workstations and the file server or hubs. Each workstation and file server on a wireless network has some sort of transceiver/antenna to send and receive the data. Information is relayed between transceivers as if they were physically connected. For longer distance, wireless communications can also take place through cellular telephone technology, microwave transmission, or by satellite.
Wireless networks are great for allowing laptop computers or remote computers to connect to the LAN. Wireless networks are also beneficial in older buildings where it may be difficult or impossible to install cables.
The two most common types of infrared communications used in schools are line-of-sight and scattered broadcast. Line-of-sight communication means that there must be an unblocked direct line between the workstation and the transceiver. If a person walks within the line-of-sight while there is a transmission, the information would need to be sent again. This kind of obstruction can slow down the wireless network.
Scattered infrared communication is a broadcast of infrared transmissions sent out in multiple directions that bounces off walls and ceilings until it eventually hits the receiver. Networking communications with laser are virtually the same as line-of-sight infrared networks.
Wireless LANs have several disadvantages. They provide poor security, and are susceptible to interference from lights and electronic devices. They are also slower than LANs using cabling.

Installing Cable - Some Guidelines

When running cable, it is best to follow a few simple rules:
  • Always use more cable than you need. Leave plenty of slack.
  • Test every part of a network as you install it. Even if it is brand new, it may have problems that will be difficult to isolate later.
  • Stay at least 3 feet away from fluorescent light boxes and other sources of electrical interference.
  • If it is necessary to run cable across the floor, cover the cable with cable protectors.
  • Label both ends of each cable.
  • Use cable ties (not tape) to keep cables in the same location together.


What is a Network Operating System?


Unlike operating systems, such as DOS and Windows, that are designed for single users to control one computer, network operating systems (NOS) coordinate the activities of multiple computers across a network. The network operating system acts as a director to keep the network running smoothly.
The two major types of network operating systems are:

Peer-to-Peer

Peer-to-peer network operating systems allow users to share resources and files located on their computers and to access shared resources found on other computers. However, they do not have a file server or a centralized management source (See fig. 1). In a peer-to-peer network, all computers are considered equal; they all have the same abilities to use the resources available on the network. Peer-to-peer networks are designed primarily for small to medium local area networks. AppleShare and Windows for Workgroups are examples of programs that can function as peer-to-peer network operating systems.

Fig. 1. Peer-to-peer network

Advantages of a peer-to-peer network:

  • Less initial expense - No need for a dedicated server.
  • Setup - An operating system (such as Windows XP) already in place may only need to be reconfigured for peer-to-peer operations.

Disadvantages of a peer-to-peer network:

  • Decentralized - No central repository for files and applications.
  • Security - Does not provide the security available on a client/server network.

Client/Server

Client/server network operating systems allow the network to centralize functions and applications in one or more dedicated file servers (See fig. 2). The file servers become the heart of the system, providing access to resources and providing security. Individual workstations (clients) have access to the resources available on the file servers. The network operating system provides the mechanism to integrate all the components of the network and allow multiple users to simultaneously share the same resources irrespective of physical location. Novell Netware and Windows 2000 Server are examples of client/server network operating systems.

Fig. 2. Client/server network

Advantages of a client/server network:

  • Centralized - Resources and data security are controlled through the server.
  • Scalability - Any or all elements can be replaced individually as needs increase.
  • Flexibility - New technology can be easily integrated into system.
  • Interoperability - All components (client/network/server) work together.
  • Accessibility - Server can be accessed remotely and across multiple platforms.

Disadvantages of a client/server network:

  • Expense - Requires initial investment in dedicated server.
  • Maintenance - Large networks will require a staff to ensure efficient operation.
  • Dependence - When server goes down, operations will cease across the network.

Examples of network operating systems

The following list includes some of the more popular peer-to-peer and client/server network operating systems.

What is a Protocol?


A protocol is a set of rules that governs the communications between computers on a network. These rules include guidelines that regulate the following characteristics of a network: access method, allowed physical topologies, types of cabling, and speed of data transfer.
See the Topology and Cabling sections of this tutorial for more information.
The most common protocols are:

Ethernet

The Ethernet protocol is by far the most widely used. Ethernet uses an access method called CSMA/CD (Carrier Sense Multiple Access/Collision Detection). This is a system where each computer listens to the cable before sending anything through the network. If the network is clear, the computer will transmit. If some other node is already transmitting on the cable, the computer will wait and try again when the line is clear. Sometimes, two computers attempt to transmit at the same instant. When this happens a collision occurs. Each computer then backs off and waits a random amount of time before attempting to retransmit. With this access method, it is normal to have collisions. However, the delay caused by collisions and retransmitting is very small and does not normally effect the speed of transmission on the network.
The Ethernet protocol allows for linear bus, star, or tree topologies. Data can be transmitted over wireless access points, twisted pair, coaxial, or fiber optic cable at a speed of 10 Mbps up to 1000 Mbps.

Fast Ethernet

To allow for an increased speed of transmission, the Ethernet protocol has developed a new standard that supports 100 Mbps. This is commonly called Fast Ethernet. Fast Ethernet requires the use of different, more expensive network concentrators/hubs and network interface cards. In addition, category 5 twisted pair or fiber optic cable is necessary. Fast Ethernet is becoming common in schools that have been recently wired.

Gigabit Ethernet

The most recent development in the Ethernet standard is a protocol that has a transmission speed of 1 Gbps. Gigabit Ethernet is primarily used for backbones on a network at this time. In the future, it will probably be used for workstation and server connections also. It can be used with both fiber optic cabling and copper. The 1000BaseTX, the copper cable used for Gigabit Ethernet, is expected to become the formal standard in 1999.

LocalTalk

LocalTalk is a network protocol that was developed by Apple Computer, Inc. for Macintosh computers. The method used by LocalTalk is called CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance). It is similar to CSMA/CD except that a computer signals its intent to transmit before it actually does so. LocalTalk adapters and special twisted pair cable can be used to connect a series of computers through the serial port. The Macintosh operating system allows the establishment of a peer-to-peer network without the need for additional software. With the addition of the server version of AppleShare software, a client/server network can be established.
The LocalTalk protocol allows for linear bus, star, or tree topologies using twisted pair cable. A primary disadvantage of LocalTalk is speed. Its speed of transmission is only 230 Kbps.

Token Ring

The Token Ring protocol was developed by IBM in the mid-1980s. The access method used involves token-passing. In Token Ring, the computers are connected so that the signal travels around the network from one computer to another in a logical ring. A single electronic token moves around the ring from one computer to the next. If a computer does not have information to transmit, it simply passes the token on to the next workstation. If a computer wishes to transmit and receives an empty token, it attaches data to the token. The token then proceeds around the ring until it comes to the computer for which the data is meant. At this point, the data is captured by the receiving computer. The Token Ring protocol requires a star-wired ring using twisted pair or fiber optic cable. It can operate at transmission speeds of 4 Mbps or 16 Mbps. Due to the increasing popularity of Ethernet, the use of Token Ring in school environments has decreased.

FDDI

Fiber Distributed Data Interface (FDDI) is a network protocol that is used primarily to interconnect two or more local area networks, often over large distances. The access method used by FDDI involves token-passing. FDDI uses a dual ring physical topology. Transmission normally occurs on one of the rings; however, if a break occurs, the system keeps information moving by automatically using portions of the second ring to create a new complete ring. A major advantage of FDDI is speed. It operates over fiber optic cable at 100 Mbps.

ATM

Asynchronous Transfer Mode (ATM) is a network protocol that transmits data at a speed of 155 Mbps and higher. ATM works by transmitting all data in small packets of a fixed size; whereas, other protocols transfer variable length packets. ATM supports a variety of media such as video, CD-quality audio, and imaging. ATM employs a star topology, which can work with fiber optic as well as twisted pair cable.
ATM is most often used to interconnect two or more local area networks. It is also frequently used by Internet Service Providers to utilize high-speed access to the Internet for their clients. As ATM technology becomes more cost-effective, it will provide another solution for constructing faster local area networks.

Protocol Summary

Protocol
Cable
Speed
Topology
Ethernet
Twisted Pair, Coaxial, Fiber
10 Mbps
Linear Bus, Star, Tree
Fast Ethernet
Twisted Pair, Fiber
100 Mbps
Star
LocalTalk
Twisted Pair
.23 Mbps
Linear Bus or Star
Token Ring
Twisted Pair
4 Mbps - 16 Mbps
Star-Wired Ring
FDDI
Fiber
100 Mbps
Dual ring
ATM
Twisted Pair, Fiber
155-2488 Mbps
Linear Bus, Star, Tree

What is Networking Hardware?


Networking hardware includes all computers, peripherals, interface cards and other equipment needed to perform data-processing and communications within the network. CLICK on the terms below to learn more about those pieces of networking hardware.

This section provides information on the following components:

File Servers

A file server stands at the heart of most networks. It is a very fast computer with a large amount of RAM and storage space, along with a fast network interface card. The network operating system software resides on this computer, along with any software applications and data files that need to be shared.
The file server controls the communication of information between the nodes on a network. For example, it may be asked to send a word processor program to one workstation, receive a database file from another workstation, and store an e-mail message during the same time period. This requires a computer that can store a lot of information and share it very quickly. File servers should have at least the following characteristics:
  • 800 megahertz or faster microprocessor (Pentium 3 or 4, G4 or G5)
  • A fast hard drive with at least 120 gigabytes of storage
  • A RAID (Redundant Array of Inexpensive Disks) to preserve data after a disk casualty
  • A tape back-up unit (i.e. DAT, JAZ, Zip, or CD-RW drive)
  • Numerous expansion slots
  • Fast network interface card
  • At least of 512 MB of RAM

Workstations

All of the user computers connected to a network are called workstations. A typical workstation is a computer that is configured with a network interface card, networking software, and the appropriate cables. Workstations do not necessarily need floppy disk drives because files can be saved on the file server. Almost any computer can serve as a network workstation.

Network Interface Cards

The network interface card (NIC) provides the physical connection between the network and the computer workstation. Most NICs are internal, with the card fitting into an expansion slot inside the computer. Some computers, such as Mac Classics, use external boxes which are attached to a serial port or a SCSI port. Laptop computers can now be purchased with a network interface card built-in or with network cards that slip into a PCMCIA slot.
Network interface cards are a major factor in determining the speed and performance of a network. It is a good idea to use the fastest network card available for the type of workstation you are using.
The three most common network interface connections are Ethernet cards, LocalTalk connectors, and Token Ring cards. According to a International Data Corporation study, Ethernet is the most popular, followed by Token Ring and LocalTalk (Sant'Angelo, R. (1995). NetWare Unleashed, Indianapolis, IN: Sams Publishing).

Ethernet Cards

Ethernet cards are usually purchased separately from a computer, although many computers (such as the Macintosh) now include an option for a pre-installed Ethernet card. Ethernet cards contain connections for either coaxial or twisted pair cables (or both) (See fig. 1). If it is designed for coaxial cable, the connection will be BNC. If it is designed for twisted pair, it will have a RJ-45 connection. Some Ethernet cards also contain an AUI connector. This can be used to attach coaxial, twisted pair, or fiber optics cable to an Ethernet card. When this method is used there is always an external transceiver attached to the workstation. (See the Cabling section for more information on connectors.)

Fig. 1. Ethernet card.
From top to bottom:
RJ-45, AUI, and BNC connectors

LocalTalk Connectors

LocalTalk is Apple's built-in solution for networking Macintosh computers. It utilizes a special adapter box and a cable that plugs into the printer port of a Macintosh (See fig. 2). A major disadvantage of LocalTalk is that it is slow in comparison to Ethernet. Most Ethernet connections operate at 10 Mbps (Megabits per second). In contrast, LocalTalk operates at only 230 Kbps (or .23 Mbps).

Fig.2. LocalTalk connectors
Ethernet Cards vs. LocalTalk Connections
Ethernet
LocalTalk
Fast data transfer (10 to 100 Mbps)
Slow data transfer (.23 Mbps)
Expensive - purchased separately
Built into Macintosh computers
Requires computer slot
No computer slot necessary
Available for most computers
Works only on Macintosh computers

Requires computer slot
No computer slot necessary
Available for most computers
Works only on Macintosh computers

Token Ring Cards

Token Ring network cards look similar to Ethernet cards. One visible difference is the type of connector on the back end of the card. Token Ring cards generally have a nine pin DIN type connector to attach the card to the network cable.

Switch

A concentrator is a device that provides a central connection point for cables from workstations, servers, and peripherals. In a star topology, twisted-pair wire is run from each workstation to a central switch/hub. Most switches are active, that is they electrically amplify the signal as it moves from one device to another. Switches no longer broadcast network packets as hubs did in the past, they memorize addressing of computers and send the information to the correct location directly. Switches are:
  • Usually configured with 8, 12, or 24 RJ-45 ports
  • Often used in a star or star-wired ring topology
  • Sold with specialized software for port management
  • Also called hubs
  • Usually installed in a standardized metal rack that also may store netmodems, bridges, or routers

Repeaters

Since a signal loses strength as it passes along a cable, it is often necessary to boost the signal with a device called a repeater. The repeater electrically amplifies the signal it receives and rebroadcasts it. Repeaters can be separate devices or they can be incorporated into a concentrator. They are used when the total length of your network cable exceeds the standards set for the type of cable being used.
A good example of the use of repeaters would be in a local area network using a star topology with unshielded twisted-pair cabling. The length limit for unshielded twisted-pair cable is 100 meters. The most common configuration is for each workstation to be connected by twisted-pair cable to a multi-port active concentrator. The concentrator amplifies all the signals that pass through it allowing for the total length of cable on the network to exceed the 100 meter limit.

Bridges

A bridge is a device that allows you to segment a large network into two smaller, more efficient networks. If you are adding to an older wiring scheme and want the new network to be up-to-date, a bridge can connect the two.
A bridge monitors the information traffic on both sides of the network so that it can pass packets of information to the correct location. Most bridges can "listen" to the network and automatically figure out the address of each computer on both sides of the bridge. The bridge can inspect each message and, if necessary, broadcast it on the other side of the network.
The bridge manages the traffic to maintain optimum performance on both sides of the network. You might say that the bridge is like a traffic cop at a busy intersection during rush hour. It keeps information flowing on both sides of the network, but it does not allow unnecessary traffic through. Bridges can be used to connect different types of cabling, or physical topologies. They must, however, be used between networks with the same protocol.

Routers

A router translates information from one network to another; it is similar to a superintelligent bridge. Routers select the best path to route a message, based on the destination address and origin. The router can direct traffic to prevent head-on collisions, and is smart enough to know when to direct traffic along back roads and shortcuts.
While bridges know the addresses of all computers on each side of the network, routers know the addresses of computers, bridges, and other routers on the network. Routers can even "listen" to the entire network to determine which sections are busiest -- they can then redirect data around those sections until they clear up.
If you have a school LAN that you want to connect to the Internet, you will need to purchase a router. In this case, the router serves as the translator between the information on your LAN and the Internet. It also determines the best route to send the data over the Internet. Routers can:

Monday, 18 April 2011

How to UTP Cabling


UTP, stands for “unshielded twisted pair”. Called unshielded because less resistant to electromagnetic interference. And called twisted pair as it includes couples who are prepared spiral cable berlilitan alias each other. There are 5 categories of UTP cable. From category 1 to category 5. For the famous computer network is a category 3 and category 5.
Category 3 can be used for data transmission up to 10 mbps, while category 5 to 100 mbps. If only create such a network in your office or campus computer or internet cafe, yes the most efficient use of the category 3. That was more than enough.
As far as the writer there are many brands on the market, it’s just that stubborn and relatively cheap famous brand is Belden – Made in USA. If you want a cheaper and use a lot, then just buy one box, approximately 150 meters in length. Do not forget to buy the connectors. Shaped like a telephone socket connector only bigger.
Another very important, you must have a special pliers for installing the connector to the UTP cable, fancy term is “the crimp tool.” This tool is useful to ‘turn off’ or ‘planting’ connector to the UTP cable. So once already in the ‘tang’, then it can not be removed again connectors. And if you want a more OK, I’ll not bear the same buy a LAN tester. You can buy a brand from Taiwan just so much cheaper. Shaped like a box and there are LED lights his eight pairs and can-blink-resistant.
OK now you ready tools, the authors start. In general, the UTP cabling are of two types, namely straight and cross type. Type is called straight because each cable corresponding numbers were 1-1 8, directly. While called a cross because there are crosses on the composition of the cord. Confused?
OK! For the straight type is used to connect the cable from the client to the hub. While for the type of cross is to the client directly connected to the client (cpu to cpu) or also from hub to hub.
We first discuss the types of straight 
This type is most easily made. Why? Because the direct correspondence 1-1. Standard sequence like this: 2 orange – green 1 – 2 blue – green 1 – 2 brown. 2 orange here meaning the same pair of young orange dark orange and so on. But do not come standard staining was also really no problem. The important sequence of the cord. For example the first end of the first order of pins young orange, the other end of the first order of the pins must also be young orange, so between the end connect to each other. Actually, not all pins are used.
The important thing is the pin numbers 1,2,3 and 6. So for example which are connected only pins 1,2,3 and 6 while the other pins are not installed, no problem. For more details, please see the picture below is the author of a book of photographs.
Who left the order for the type of correspondence straight, the right of the cross
Time will install it, then cut the tip of the cord, then stacking the cord then flattened with a knife cutting at the crimp tool available. Andak not have to bother to let go at the end of the cable insulation, because when you insert the cable into the connector then pressed (pressed) using a crimp tool, when it was actually there at the connector pins that penetrate down to the wire. Consider, for emphasis (pressing) a hard, hard sometimes because if you do not pin it does not penetrate into the cable insulation. If you have then you test using the LAN tester. Insert the tip ends of the wires to the device, then turn it on, if the LED lights on the LAN tester that lights up everything, from number 1 to 8 means that you have been successful. If there’s one that does not work means the possibility of the pin numbers are no problem. The easiest way is that you press (press), again using the pliers. Possibility of the pin has not been transparent. If you press but still does not connect, then try to check the correspondence between pins 1-1 or have not already. If it was true and still fail, then indeed you are not lucky. Repeat again until it works.