Monday, May 28, 2012

Understanding Protocols and Various kinds

Protocol is a set of rules that governs the communications between computers on a network , the rules include guidelines that apply to the ways or methods of accessing a network , the physical topology , cable types and data transfer speed .

Protocols are known are as follows :
- Ethernet - Token Ring
- Local Talk - FDDI

1 Ethernet
Ethernet access method called CSMA / CD ( Carrier Sense Multiple Access / Collision Detection ) . This is a system where each computer listens to the cable from the network before sending anything into it . If the network is clear, the computer will transmit the data , if there is another transmission on the cable, the computer will wait and try re- transmission if the line is clear . Sometimes, two computers attempt to transmit at the same time , when this happens , each computer will be back and will wait a random amount of data to transmit back . This method is known to the coalition , and will not affect the transmission speed of the network .
Ethernet protocol can be used for the network model linear bus, star , or tree . Data can be transmitted over twisted pair cables , coaxial , or fiber optic cable at a speed of 10 Mbps .

2 LocalTalk
LocalTalk is a network protocol that was developed by Apple Computer , Inc. . for Macintosh machines . The method used by LocalTalk is a CSMA / CA ( Carrier Sense Multiple Access with Collision Avoidance ) . Almost the same as CSMA / CD .. LocalTalk adapters and special twisted pair cable can be used to connect multiple computers through the serial port . The Macintosh operating system allows the establishment of a peer-to - peer without the need for additional specialized application protocol LocalTalk networks can be used to model the Straight Line , star , or tree models using twisted pair cable . The most striking shortage is speed . Speed ​​transmission is only 230 Kbps .

3 Token Ring
Token protocol was developed by IBM in the mid-1980s . The access method passing of a token in a circle like a ring . In a token ring , the computers are connected to each other like a ring . A token signal moving spins in a circle ( ring ) in a network and move from a computer to the computer to the next , if the stopover on one of the computers turned out to be no data to be transmitted , the token will transport it to the place where the data it wants addressed , continues to move tokens each respectively connect between computers .
Token Ring protocol requires a star network model using twisted pair cable or fiber optic cable . And can perform transmission speeds of 4 Mbps or 16 Mbps . In line with the development of Ethernet , Token Ring uses dwindle until now .

Fiber Distributed Data Interface ( FDDI ) is a network protocol that connects two or more networks even at great distances . The access method used by FDDI token . FDDI uses a dual ring physical topology . Baiasanya transmission process using one of the rings , but if any problems are found it will automatically use the second ring .
An advantage of FDDI is speed using fiber optic cable at 100 Mbps .

ATM stands for Asynchronous Transfer Mode ( ATM) is a network protocol that transmits data at a speed of 155 Mbps or more . ATM works by transmitting all data in packets where the other transfer protocols on large - size package . ATM supports a variety of media such as video , CD - audio , and images . ATM works on star topology model , using a fiber optic cable or twisted pair cable . ATMs are generally used to connect two or more LANs . he is also widely used by Internet Service Providers ( ISPs ) to increase the speed of Internet access for their clients .
The protocol in Use
The cable in use
Transfer Speed
Physical topology
Twisted Pair , Coaxial , Fiber
10 Mbps

Linear Bus , Star , Tree
Fast Ethernet
Twisted Pair , Fiber
100 Mbps
twisted Pair
0:23 Mbps
Linear Bus or Star
Token Ring
twisted Pair
4 Mbps - 16Mbps
Star - Wired Ring
100 Mbps
dual ring
Twisted Pair , Fiber
155-2488 Mbps
Linear Bus , Star , Tree
                                                Table 1.2 Conclusions for Protocol

6 The hardware needed
           Hardware needed to build a computer network , namely: Computer , Network Card , Hub , and all things related to network connections such as printers , CD-ROM , Scanner , Bridges , Routers , and other transformations necessary to process the data in the network .

- File Servers . - Repeaters .
- Workstations . - Bridges .
- Routers. - Concentrators / Hubs .
- Network Interface Cards .

7 File Servers
A file server is the heart of plumpness Network , is a very fast computer , have large memory , hard drive has a large capacity , with a fast network card . Network operating system is stored here , also includes a number of applications and data needed for the network .
A file server is in charge of controlling communication and information between nodes / components in a network . For example, managing the delivery of a database or word processing files from one workstation or node , to another node , or receive an email at the same time with other tasks . seen that the task is very complex file server . So that at least a server has beberpa characters as below :
· Processor at least 166 megahertz or faster processor ( Pentium Pro , Pentium II , PowerPC ) .
· A hard drive is a fast and large capacity of 10 GB or less
· A RAID ( Redundant Array of Inexpensive Disks ) .
· A tape for backing up the data ( for example . DAT , JAZ , Zip , or CDRW )
· A lot of network ports
· Network card is fast and Reliability
· Approximately 32 MB of memory
8 Workstations
Overall computer connected to a file server in a network is referred to as a workstation . A workstation has a minimum ; Network card , network applications ( network software ) , cable to connect to a network , usually a workstation that does not require Floppy because the data you want in the store and can be placed on the file server . Almost any computer can be used as a computer workstation .

9 Network Interface Cards ( NICs ) or Network Card
Network Card ( NIC ) is a device that provides the means to connect between computers , most of the network card is inernal card , network card that is installed in the expansion slot inside the computer .
Some computers such as MAC computer , using a special box that is plugged into the serial port of the computer or SCSI port . There is a slot on your notebook computer to a network card commonly called PCMCIA slot .
Multiple network cards in use today are : Ethernet network cards , LocalTalk connectors , and Token Ring network card . That is popularly used today is Ethernet , then followed by Token Ring, and LocalTalk

10 Ethernet Card / Network Card Ethernet
Ethernet cards are usually purchased separately from the computer , except as Macintosh computers already quote ethernet network card in it . Ethernet network cards generally have to provide the connection port for coaxial cable or twisted pair cable , if it is designed for coaxial cable BNC konenektorya is , and if it is designed for twisted pair cable will have RJ-45 connectors . Some ethernet network card sometimes also have an AUI connector . All of it in , connect to a coaxial , twisted pair , or with fiber optic cable.

11 LocalTalk Connectors / Connectors LocalTalk
LocalTalk is a network card for macintosh computers , using a special adapter box and cable attached to the port for the printer . Disadvantages of LocalTalk than Ethernet is a data transfer rate of speed , bi Ethernet computer network is not something new at this time .
Almost every company there is a computer network to facilitate the flow of information within the perudahaan . Internet is gaining popularity today is a giant computer network is a network of computer networks that are connected to each other and interact . This can occur because of the development of network technology very rapidly , so that within a few years the number of users of computer networks that are members of the Internet can ganda.asanya doubled to 10 Mbps , while LocalTalk can only operate at a speed of 230 Kbps or equal to 0:23 Mps
12 Token Ring Cards
Token Ring network cards look almost identical to an Ethernet network card . One difference is the type of connector on the back of the card networks , Token Ring generally has a 9 pin DIN -type connector that connects to the network card Cable Network .

13 Hub / Concentrator
A concentrator / hub is a device that unites network cables from each workstation , server or other device . In a star topology , twisted pair cable coming from a workstation to log into the hub . Hubs have many slots concentrator which can be fitted according to the port number of the card in question.
The characteristics possessed Concentrator is :
· It usually consists of 8 , 12 , or 24- port RJ - 45
· Used in star topology / Star
· Usually sold with special applications ie applications that set the Management port .
· Usually called hubs
· Usually in pairs on a special shelf , in which there is Bridges , routers

14 Repeaters
The easiest example is on a LAN using star topology using unshielded twisted pair cable . Where known maximum length for a twisted pair cable unshileded is 100 meters , then to amplify the signal from the cable dipasanglah a repeater on the network .

15 Bridges / Bridges
Is a device that divides a single network into two networks , is used to obtain an efficient network , which is sometimes very fast growing network bridge so in need for it . Most Bridges can know each address of each computer on the network segment next to it and also on other network beside him anyway . Likened to that Bridges is like a traffic cop at the crossroads governing during rush hour . He manages to keep the information on both sides of the road network remains properly and regularly . Bridges can also be used to connect them between networks that use different cable types or different topologies .

16 Routers
A Router interpret informaari from one network to another , he is similar to Bridge , but rather clever bit , the router will search for the best path to send a message Based on the above address and a destination address of origin .
Routers know the address komputerr , bridges and other routers . router can know the entire network see which side is the most busy and he can pull the data from the busy side to side of the net .
If a company has a LAN and want to connect to the Internet , they have to buy a router . This means that a router can translate information between your LAN and the Internet . This also means finding the best alternative path to transmit the data passing through the Internet . This means the router :
· Set the signal path efficiently
· Set the message between the two protocols
· Organize messages between linear bus network topology and star ( star ) Set the message passing between Fiber optic cables , cable or twisted pair cable koaaksialm .


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