What is a Network?
A network consists of two or more computers that are linked in order to share resources (such as printers and CD-ROMs), exchange files, or allow electronic communications. The computers on a network may be linked through cables, telephone lines, radio waves, satellites, or infrared light beams.
Point-to-Point Network Definition
This type of network consists of many connections between individual pairs of machines. To go from the source to the destination, a packet of information on this type of network may have to first visit one or more intermediate machines. Often multiple routes, of different length are possible, so routing algorithms play an important role in point-to-point networks.
As a general rule (although there are many exceptions), smaller, geographically localized networks tend to use broadcasting, whereas larger networks usually are point-to-point.
Local Area Network (LAN) Definition
This type of network is generally called a LAN and are privately-owned networks within a single building or campus of up to a few miles in size. They are widely used to connect personal computers and workstations in company offices and factories to share resources (e.g. printers) and exchange information. LANs are distinguished from other kinds of networks by three characteristics: 1) their size, 2) their transmission technology, and 3) their topology.
LANs are restricted in size, which means that they worst-case transmission time is bounded and known in advance. Knowing this bound makes it possible to use certain kinds of designs that would not otherwise be possible. IT also simplifies network management.
LANs often use a transmission technology consisting of a single cable to which all the machines are attached, like the telephone company party lines once used in rural areas. Traditional LANs run at speeds of 10 to 100 Mbps, have low delay (tens of microseconds), and make very few errors.
Wide Area Network (WAN) Definition
This type of network spans a large geographical area, often a country or continent. IT contains a collection of machines intended for running user programs. These machines are called hosts or end systems. The hosts are connected by a communication subnet. The job of the subnet is to carry messages from host to host, just as the telephone system carries words from speaker to listener. By separating the pure communication aspects of the network from the application aspects, the complete network design is greatly simplified.
In most wide area networks, the subnet consists of two distinct components: transmission lines and switching elements. Transmission lines, also called circuits, channels, or trunks move bits between machines.
The switching elements are specialized computers used to connect two or more transmission lines. When data arrive on an incoming line, the switching element must choose and outgoing line to forward them on. Unfortunately, there is no standard terminology used to name these computers. They are variously called packet switching nodes, intermediate systems, and data switching exchanges among other things. The generic term for the switching equipment is a router.
In most WANs, the network contains numerous cables or telephone lines, each on connecting a pair of routers. If two routers that do not share a cable nevertheless wish to communication, the must do this indirectly, via other routers.
Wireless network
Wireless network refers to any type of computer network that is wireless, and is commonly associated with a telecommunications network whose interconnections between nodes is implemented without the use of wires. Wireless telecommunications networks are generally implemented with some type of remote information transmission system that uses electromagnetic waves, such as radio waves, for the carrier and this implementation usually takes place at the physical level or "layer" of the network.
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Definition of Modem
Modem is actually an odd acronym for Modulator-Demodulator. A modem takes a digital signal from your computer and converts to an analog signal so that it can be transferred through a phone line. This conversion is necessary because modems make use of regular phone lines which are analog. Newer technologies don't require this conversion, but more often than not, the term modem is still used.
Since modems use phone lines, their transfer speeds are limited. The best modems can transmit data at approximately 56KB/s or maybe 112KB/s on a good day. That might seem like a lot except when you compare it to a typical corporate network or to broadband where speeds can easily reach 1000 KB/s
Definition of OutsourcingOutsourcing is usually the term used when a company takes a part of its business and gives that part to another company. In recent times, the terms has been most commonly used for technology related initiatives such as handing over the IT help-desk to a third-party. But it can also refer to non-technical services such as handing over the telephone-based customer service department.
The recipients for outsourced activities are generally in the same country. When a company on another continent is involved e.g.
Definition of Supply Chain Management
Supply chain management (SCM) is the oversight of materials, information, and finances as they move in a process from supplier to manufacturer to wholesaler to retailer to consumer. Supply chain management involves coordinating and integrating these flows both within and among companies. It is said that the ultimate goal of any effective supply chain management system is to reduce inventory (with the assumption that products are available when needed). As a solution for successful supply chain management, sophisticated software systems with Web interfaces are competing with Web-based application service providers (ASP) who promise to provide part or all of the SCM service for companies who rent their service.
Supply chain management flows can be divided into three main flows:
- The product flow
- The information flow
- The finances flow
The product flow includes the movement of goods from a supplier to a customer, as well as any customer returns or service needs. The information flow involves transmitting orders and updating the status of delivery. The financial flow consists of credit terms, payment schedules, and consignment and title ownership arrangements. There are two main types of SCM software: planning applications and execution applications. Planning applications use advanced algorithms to determine the best way to fill an order. Execution applications track the physical status of goods, the management of materials, and
financial information involving all parties.
Some SCM applications are based on open data models that support the sharing of data both inside and outside the enterprise (this is called the extended enterprise, and includes key suppliers, manufacturers, and end customers of a specific company). This shared data may reside in diverse database systems, or data warehouses, at several different sites and companies.
By sharing this data "upstream" (with a company's suppliers) and "downstream" (with a company's clients), SCM applications have the potential to improve the time-to-market of products, reduce costs, and allow all parties in the supply chain to better manage current resources and plan for future needs.
Increasing numbers of companies are turning to Web sites and Web-based applications as part of the SCM solution. A number of major Web sites offer e-procurement marketplaces where manufacturers can trade and even make auction bids with suppliers.
