Local Area Network (LAN) is a number of interconnected computers linked together in a certain area is not so large, as in an office or building. Broadly speaking there are two types of network or LAN, a network of Peer to Peer and Client-Server networks.In peer to peer network, each computer connected to the network can act both as a workstation or server. While the client-server network, a single computer to serve as a server and other computer acts as a workstation. Between these two types of networks each have advantages and disadvantages.
Use of the LAN itself cause all computers connected in a network can exchange data or otherwise related. This partnership has grown from a mere exchange of data to jointly use of equipment. LAN is usually the hub, the hub will follow the principles of the work itself. In this case is that the hub does not have knowledge of the destination address to a broadcast data delivery, and also because the hub has only one collision domain so that if one port is busy, the other ports have to wait.
LAN is composed of several basic elements that include hardware and software, namely:
1. Physical Components: Computer (PC), Network Interface Card (NIC), cable, network topology.
- The type of computer used in the network will determine the performance of the network. Computers with high performance will be able to send and access data in the network quickly. In the Client-Server type networks, computer servers that functioned as an absolute must have higher performance than any other computer as a workstation, because the server will be on duty to provide facilities and manage the network operation.
-Based on the type of bus, there is some type of network interface card (NIC) or network card, the ISA and PCI. Currently, there are many types of network card is used, for example PCI.
-Cabling
1. Twisted Pair Cable
• This cable is divided into two, Shielded Twisted Pair and Unshielded Twisted Pair (UTP)
• More widely known as a telephone cable
• Relatively inexpensive
• Short Distance
• Easily influenced by disturbances
• Speed of data that can be supported is limited, 10-16 Mbps
2. Coaxial cable
• Commonly used in television
• The distance is relatively far
• High speed data transmission over the appeal Twisted Pair, 30 Mbps
• Prices are relatively inexpensive • larger size of the Twisted Pair
3. Fiber Optic Cables
• long distance
• higher data speeds, 100 Mbps
• The relatively small size
• Confidential affected disorder
• Prices are still relatively expensive
• Installation is relatively difficult
Network Topology
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Network topology is the arrangement of data flow path in the physical network that
connects one node to another node. Topology is a way of connecting computers to each other to form a network of computers. The bus, token-ring, star and peer-to-peer network. Each has a characteristic topology, with the advantages and disadvantages.
Topology refers to the network and adapt to the situation existing in-field (possible or not used one topology). But the whole grand design of the network (the selection of equipment, accessories, active / passive device) and the policy / policy to be applied after the completion of a project, the selection will be based on the formation of network topology.
The types of general topology:
STAR Topology
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Centralized control, all links must be channeled through the center of the node's data or the client chooses. Node central server called the station and other primary or secondary station is called a server or client. After starting the server network connection, every time any client server can use the network connection without waiting for commands from the server.
Gain:
• Most flexible
• Installing / changing station is very simple and does not interfere with other parts of
the network
• Centralized control
• Access detection and isolation of errors / defects
• network management / amenities
• Loss
• Need special handling
• Centralized Control (HUB) to be a critical element
BUS Topology
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Gain:
- Save Cable
- Layout simple cable
- Easy to develop
Losses:
- Fault detection and isolation of very small
- The traffic density
- If a client is broken, so the network can not work.
- Required for remote repeater
Topology TokenRING
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Token-ring method (often called ring only) is the way a computer connects to the ring-shaped (circles). Each node has the same form. The network will be referred to as a loop,data is sent through each node and each node received information that addresses whether the data is checked for it or not.
Gain:
- Save Cables
Losses:
- Sensitive errors
- Development of a more rigid network
2. Component Software: Network Operating Systems, Network Adapter Driver, Network Protocol.
TCP / IP protocol
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TCP / IP (Transmission Control Protocol / Internet Protocol) is a group of protocols that manage computer data communications on the Internet. Computers that connect to the internet to communicate with TCP / IP protocol, it uses the same language and different type of computer operating system is not a problem. PC with Windows operating systems can communicate with Macintosh computers or the Sun SPARC running Solaris.
So, if a computer using TCP / IP and directly connected to the internet, so the computer can communicate with a computer anywhere in the world which is also connected to the internet. Because an important role in the Windows operating system as well as TCP / IP is the protocol options (default) from Windows. TCP is the transport layer of the OSI model (Open Systems interconnection), while the IP is the Network layer of the OSI mode.
IP Address
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IP address is the address given on computer networks and network equipment that uses TCP / IP protocol. IP addresses consist of 32-bit binary numbers that can be written as four groups of decimal numbers separated by dots such as 192.168.0.1.
Examples of IP address
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Network ID │ Host ID
192 │ 168 │ 1 │ 0
IP addresses consist of two parts: network ID and host ID, network ID to determine which network addresses, while the host ID to determine the host address (computers, routers, switches).
Therefore, giving full address of the IP address of a host and a network address where the host is located.
IP Address Classes
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For ease of use, depending on the needs of users, IP addresses are divided into three classes as shown in the table.
IP Address Classes
IP address assigned to the class A network with a very large number of hosts. IP Range
1.xxx.xxx.xxx. - 126.xxx.xxx.xxx, there were 16,777,214 (16 million), the IP address of each class A. IP address assigned to the class A network with a very large number of hosts. In class A IP address, network ID is the first 8 bits, while the host ID is 24 bits next.
Therefore, how to read the IP address class A, for example, 113.46.5.6 is:
Network ID = 113
Host ID = 46.5.6
So that means that the host IP address on the network number number 113 46.5.6.
Class B IP address is usually allocated for medium and large sized networks. In class B IP address, network ID is the first 16 bits, while the host ID is 16 bits next. Therefore, how to read a class B IP address, eg
132.92.121.1
Network ID = 132.92
Host ID = 121.1
So that means that the IP address on a network host number 121.1 in the number 132.92. length 16-bit host ID, network with the IP address of class B can accommodate about 65,000 hosts. Range IP128.0.xxx.xxx - 191.155.xxx.xxx
Class C IP address originally used for small networks (LAN). Host ID is the last 8 bits. With this configuration, can be formed about 2 million networks with each network has 256 IP addresses. IP Range 192.0.0.xxx - 223.255.255.x.
The allocation of IP address is basically a process of selecting the network Id and the correct host ID for a network. Accurate or not this configuration depends on the purpose to be achieved, which allocates an IP address as efficiently as possible.
Domain Name System (DNS)
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Domain Name System (DNS) is a system that allows the name of a host computer on the network or the Internet translated into an IP address.
In giving the name, the DNS uses a hierarchy architecture.
1. Root-level domain: the top level is shown as a dot (.).
2. Top level domain: the category code of such organization or country. Com for use by the company; .edu for use by the college; .gov for use by government agencies. In addition to distinguishing the use of the name of a country to another use such marks .id to Indonesia or .au for Australia.
3. Second level domain: the name for the organization or company, for example:
microsoft.com, yahoo.com, and others.
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