what is a network
Computers: A group of interconnected computers and peripherals that is capable of sharing software and hardware resources between many users. The internet is a global network of networks. See also local area network and wide area network
Common types of area networks are
Short name Original name
LAN Local Area Network
Wan Wide Area Network
WLAN Wireless Local Area Network
MAN Metropolitan Area Network
SAN Storage Area Network
System Area Network
Small Area Network.
Server Area Network
Local Area NetworkA local area network is a collection of computers and associated devices that share a common communications line or wireless link to a server. Typically, a LAN encompasses computers and peripherals connected to a server within a distinct geographic area such as an office or a commercial establishment. Processers and other mobile devices use a LAN joining to share resources such as a printer or network storage.
A local area network may serve as few as two or three users (for example, in a small-office network) or several hundred users in a larger office. LAN networking comprises cables, switches, routers and other components that let users connect to internal servers, websites and other LANs via wide area network.
Ethernet and Wi-Fi are the two primary ways to enable LAN connections. Ethernet is a specification that enables computers to join with each other. and partition their networks without the need for major infrastructure changes. Typically, a suite of application programs can be kept on the LAN server. Workers who want an application frequently can download it once and then run it from their local device. Users can order printing and other services as needed through applications run on the LAN server. A user can share files with others stored on the LAN server; read and write access is maintained by a network administrator
Wide Area Network
wide area network is a communications network that spans a large geographic area such as across cities, states, or countries. They can be private to connect parts of a business or they can be more public to connect smaller networks together.
-62230161861500The easiest way to know what a WAN is to think of the internet as a whole, which is the world’s largest WAN. The internet is a WAN because, through the use of isps, it connects lots of smaller local area network or metro area networks.
Note-: – The acronym WAN is sometimes used to describe a wireless area network, though it’s most often abbreviated as WLAN.
Since WANs, by definition, cover a larger distance than LANs, it makes sense to connect the various parts of the WAN using a virtual private network. This provides protected communications between sites, which is necessary given that the data transfers are happening over the internet.
Wireless Local Area Network
-185420188785500A wireless local area network is a wireless distribution method for two or more devices that use high-frequency radio waves and often include an access point to the Internet. A WLAN allows users to move around the coverage area, often a home or small office, while maintaining a network connection. A wireless local area network should not be confused with the Wi-Fi Alliance’s Wi-Fi trademark. Wi-Fi is not a technical term but is described as a superset of the IEEE 802.11 standard and is sometimes used interchangeably with that standard. However, not every Wi-Fi device actually receives Wi-Fi Alliance certification, although Wi-Fi is used by more than 700 million people through about 750,000 Internet connection hot spots.
Every component that connects to a wireless local area is considered a station and falls into one of two categories: access points and clients. APs transmit and receive radio frequency signals with devices able to receive transmitted signals; they normally function as routers. Customers may comprise a variety of devices such as desktop computers, workstations, laptop computers, IP phones and other cell phones and Smartphones.
Metropolitan Area Network
-2617741370313A metropolitan area network is similar to a local area network (LAN) but spans an entire town or campus. MANs are shaped by connecting multiple LANs. Thus, MANs are larger than LANs but minor than wide area networks MANs are extremely effective and provide fast communication via high-speed carriers, such as fibre optic cables.
A MAN is ideal for many kinds of network users because it is a medium-size network. MANs are used to build networks with high data connection speeds for cities and towns The working mechanism of a MAN is similar to an Internet Service Provider (ISP), but a MAN is not owned by a single organization. Like a WAN, a MAN provides shared network connections to its users
Storage Area Network
A storage area network is a secure high-speed data transfer network that provides access to consolidated block-level storage. A storage area network makes a network of storage devices accessible to multiple servers. storage area network devices appear to servers as attached drives, eliminating traditional network bottlenecks.
storage area network is sometimes also referred to (albeit redundantly) as storage area network, storage area network, network storage area network etc.
The advantages of SAN include:
Storage Virtualization: Server capacity is no longer linked to single storage devices, as large and consolidated storage pools are now available for software applications.
High-Speed Disk Technologies: An example is FC, which offers data retrieval speeds that exceed 5 Gbps. Storage-to-storage data transfer is also available via direct data transmission from the source to the target device with minimal or no server intervention.
What is topology
right937672Topology is a branch of mathematics that describes mathematical spaces, in particular the properties that stem from a space’s shape. Many of the shapes topologists deal with are incredibly strange, so much so that practically all everyday objects such as bowls and pets and trees make up a small minority.
-35784840933400Bus topology is a network type in which every computer and network device is connected to single cable. When it has exactly two endpoints, then it is called Linear Bus topology.
Features of BUS Topology
It transmits data only in one direction.
Every device is connected to a single cable
Advantages of BUS Topology
It is cost effective.
Cable required is least compared to another network topology.
Used in small networks.
It is easy to understand.
Easy to expand joining two cables together.
Disadvantages of BUS Topology
Cables fails then whole network fails.
If network traffic is heavy or nodes are more the performance of the network decreases.
Cable has a limited length.
It is slower than the ring topology.
left58241500It is called ring topology because it forms a ring as each computer is connected to another computer, with the last one connected to the first. Exactly two neighbours for each device.
Features of Ring Topology
A number of repeaters are used for Ring topology with large number of nodes, because if someone wants to send some data to the last node in the ring topology with 100 nodes, then the data will have to pass through 99 nodes to reach the 100th node.
The transmission is unidirectional, but it can be made bidirectional by having 2 connections between each Network Node, it is called Dual Ring Topology.
Advantages of Ring Topology
Transmitting network is not affected by high traffic or by adding more nodes, as only the nodes having tokens can transmit data.
Cheap to install and expand
Disadvantages of Ring Topology
Troubleshooting is difficult in ring topology.
Adding or deleting the computers disturbs the network activity
Failure of one computer disturbs the whole network.
In this type of topology all the computers are connected to a single hub through a cable. This hub is the central node and all others nodes are connected to the central node.
Features of Star Topology
Every node has its own dedicated connection to the hub.
Hub acts as a repeater for data flow.
Can be used with twisted pair, Optical Fibre or coaxial cable.
Advantages of Star Topology
Fast performance with few nodes and low network traffic.
Hub can be upgraded easily.
Easy to troubleshoot.
Easy to setup and modify.
Disadvantages of Star Topology
Cost of installation is high.
Expensive to use.
If the hub fails then the whole network is stopped because all the nodes depend on the hub.
Performance is based on the hub that is it depends on its capacity
It is a point-to-point connection to other nodes or devices. All the network nodes are connected to each other. Mesh has n(n-1)/2 physical channels to link n devices.
There are two techniques to transmit data over the Mesh topology, they are:
MESH Topology: Routing
In routing, the nodes have a routing logic, as per the network requirements. Like routing logic to direct the data to reach the destination using the shortest distance. Or, routing logic which has information about the broken links, and it avoids those nodes etc. We can even have routing logic, to re-configure the failed nodes.
MESH Topology: Flooding
In flooding, the same data is transmitted to all the network nodes, hence no routing logic is required. The network is robust, and the its very unlikely to lose the data. But it leads to unwanted load over the network.
Types of Mesh Topology
Partial Mesh Topology: In this topology some of the systems are connected in the same fashion as mesh topology but some devices are only connected to two or three devices.
Full Mesh Topology: Each and every nodes or devices are connected to each other.
Features of Mesh Topology
Advantages of Mesh Topology
Each connection can carry its own data load.
It is robust.
Fault is diagnosed easily.
Provides security and privacy.
Disadvantages of Mesh Topology
Installation and configuration is difficult.
Cabling cost is more.
Bulk wiring is required.
It has a root node and all other nodes are connected to it forming a hierarchy. It is also called hierarchical topology. It should at least have three levels to the hierarchy.
Features of Tree Topology
Ideal if workstations are located in groups.
Used in Wide Area Network.
Advantages of Tree Topology
Extension of bus and star topologies.
Expansion of nodes is possible and easy.
Easily managed and maintained.
Error detection is easily done.
Disadvantages of Tree Topology
If more nodes are added maintenance is difficult.
Central hub fails, network fails.
It is two different types of topologies which is a mixture of two or more topologies. For example, if in an office in one department ring topology is used and, in another star, topology is used, connecting these topologies will result in Hybrid Topology (ring topology and star topology).
Features of Hybrid Topology
It is a combination of two or topologies
Inherits the advantages and disadvantages of the topologies included
Advantages of Hybrid Topology
Reliable as Error detecting and troubleshooting is easy.
Scalable as size can be increased easily.
Disadvantages of Hybrid Topology
Complex in design.