A Metropolitan Area Network (MAN) is a large computer network that spans a metropolitan area or campus. Its geographic scope falls between a WAN and LAN. MANs provide Internet connectivity for LANs in a metropolitan region, and connect them to wider area networks like the Internet.
A wide area network (WAN) is a network that covers a broad area (i.e., any telecommunications network that links across metropolitan, regional, national or international boundaries) using leased telecommunication lines. Business and government entities utilize WANs to relay data among employees, clients, buyers, and suppliers from various geographical locations. In essence, this mode of telecommunication allows a business to effectively carry out its daily function regardless of location. The Internet can be considered a WAN as well, and is used by businesses, governments, organizations, and individuals for almost any purpose imaginable.
- HUB - An Ethernet hub, active hub, network hub, repeater hub, multiport repeater or hub is a device for connecting multiple Ethernet devices together and making them act as a single network segment. It has multiple input/output (I/O) ports, in which a signal introduced at the input of any port appears at the output of every port except the original incoming. A hub works at the physical layer (layer 1) of the OSI model.Repeater hubs also participate in collision detection, forwarding a jam signal to all ports if it detects a collision. In addition to standard 8P8C ("RJ45") ports, some hubs may also come with a BNC /or Attachment Unit Interface (AUI) connector to allow connection to legacy 10BASE2 or 10BASE5 network segments.Hubs are now largely obsolete, having been replaced by network switches except in very old installations or specialized applications
- SWITCH - A Hubs are now largely obsolete, having been replaced by network switches except in very old installations or specialized applications.network switch is a computer networking device that connects devices together on a computer network, by using a form of packet switching to forward data to the destination device. A network switch is considered more advanced than a(repeater) hub because a switch will only forward a message to one or multiple devices that need to receive it, rather than broadcasting the same message out of each of its ports.A network switch (also called switching hub, bridging hub, officially MAC bridge) is a multi-port network bridge that processes and forwards data at the data link layer (layer 2) of the OSI model. Switches can also incorporate routing in addition to bridging; these switches are commonly known as layer-3 or multilayer switches. Switches exist for various types of networks including Fibre Channel, Asynchronous Transfer Mode, InfiniBand, Ethernet and others. The first Ethernet switch was introduced by Kalpana in 1990
- ROUTER - A router or (chiefly North American) is a networking device, commonly specialized hardware, that forwards data packets between computer networks. This creates an overlay internetwork, as a router is connected to two or more data lines from different networks. When a data packet comes in one of the lines, the router reads the address information in the packet to determine its ultimate destination. Then, using information in its routing table or routing policy, it directs the packet to the next network on its journey. Routers perform the "traffic directing" functions on the Internet. A data packet is typically forwarded from one router to another through the networks that constitute the internetwork until it reaches its destination node.The most familiar type of routers are home and small office routers that simply pass data, such as web pages, email, IM, and videos between the home computers and the Internet. An example of a router would be the owner's cable or DSL router, which connects to the Internet through an & nbsp;ISP. More sophisticated routers, such as enterprise routers, connect large business or ISP networks up to the powerful core routers that forward data at high speed along the optical fiber lines of the Internet backbone. Though routers are typically dedicated hardware devices, use of software-based routers has grown increasingly common.
- INTRANATE - An intranet is a computer network that uses Internet
Protocol technology to share information, operational systems, or computing
services within an organization. This term is used in contrast to extranet, a
network between organizations, and instead refers to a network within an
organization. Sometimes, the term refers only to the organization's internal
website, but may be a more extensive part of the organization's information
technology infrastructure, and may be composed of multiple local area networks.
The objective is to organize each individual's desktop with minimal cost, time
and effort to be more productive, cost efficient, timely, and competitive.
An intranet may host multiple private websites and
constitute an important component and focal point of internal communication and
collaboration. Any of the well known Internet protocols may be found in an
intranet, such as HTTP (web services), SMTP (e-mail), and FTP (file transfer
protocol). Internet technologies are often deployed to provide modern
interfaces to legacy information systems hosting corporate data.
In many organizations, intranets are protected from
unauthorized external access by means of a network gateway and firewall. For
smaller companies, intranets may be created simply by using private IP address
ranges. In these cases, the intranet can only be directly accessed from a
computer in the local network; however, companies may provide access to
off-site employees by using a virtual private network, or by other access
methods, requiring user authentication and encryption.
EXTRANATE - An extranet is a computer network that allows controlled
access from outside of an organization's intranet. Extranets are used for
specific use cases including business-to-business (B2B). In a
business-to-business context, an extranet can be viewed as an extension of an
organization's intranet that is extended to users outside the organization,
usually partners, vendors and suppliers, in isolation from all other Internet
users. It is in context of that isolation that an extranet is different from an
intranet or internet. In contrast, business-to-consumer (B2C) models involve
known servers of one or more companies, communicating with previously unknown
consumer users. An extranet is similar to a DMZ in that it provides access to
needed services for channel partners, without granting access to an
organization's entire network.
INTERNET - The Internet is a global system of interconnected computer
networks that use the standard Internet protocol suite (TCP/IP) to link several
billion devices worldwide. It is an international network of networks that
consists of millions of private, public, academic, business, and government
packet switched networks, linked by a broad array of electronic, wireless, and
optical networking technologies. The Internet carries an extensive range of
information resources and services, such as the inter-linked hypertext
documents and applications of the World Wide Web (WWW), the infrastructure to
support email, and peer-to-peer networks for file sharing and telephony.
The origins of the Internet date back to research
commissioned by the United States government in the 1960s to build robust,
fault-tolerant communication via computer networks. While this work, together
with work in the United Kingdom and France, led to important precursor
networks, they were not the Internet. There is no consensus on the exact date
when the modern Internet came into being, but sometime in the early to mid-1980s
is considered reasonable. From that point, the network experienced decades of
sustained exponential growth as generations of institutional, personal, and
mobile computers were connected to it.The Internet has no centralized governance in either
technological implementation or policies for access and usage; each constituent
network sets its own policies. Only the overreaching definitions of the two
principal name spaces in the Internet, the Internet Protocol address space and
the Domain Name System, are directed by a maintainer organization, the Internet
Corporation for Assigned Names and Numbers (ICANN). The technical underpinning
and standardization of the core protocols (IPv4 and IPv6) is an activity of the
Internet Engineering Task Force (IETF), a non-profit organization of loosely
affiliated international participants that anyone may associate with by contributing
technical expertise.
- Ethernet explained - Ethernet is the most used networking technology for LANs today. It defines wiring and signaling for the Physical layer of the OSI model. For the Data Link layer, it defines frame formats and protocols.
Ethernet is described as IEEE 802.3 standard. It uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access method and supports speeds up to 100 Gbps. It can use coaxial, twisted pair and fiber optic cables. Ethernet uses frames to with source and destination MAC addresses to deliver data.
NOTE:-
The term Ethernet LAN refers to a combination of computers, switches, and different kinds of cables that use the Ethernet standard to communicate over the network. It is by far the most popular LAN technology today.
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