Thursday, November 17, 2011

Different types of network devices

Switch o hub:
network switch or switching hub is a computer networking device that connects network segments.
The term commonly refers to a multi-port network bridge that processes and routes data at the data link layer (layer 2) of the OSI model. Switches that additionally process data at the network layer (Layer 3) and above are often referred to as Layer 3 switches or multilayer switches.



Router:
 In packet-switched networks such as the Internet, a router is a device or, in some cases, software in a computer, that determines the next network point to which a packet should be forwarded toward its destination. 
http://searchnetworking.techtarget.com/definition/router

Firewall:
firewall is a device or set of devices designed to permit or deny network transmissions based upon a set of rules and is frequently used to protect networks from unauthorized access while permitting legitimate communications to pass.
http://en.wikipedia.org/wiki/Firewall_(computing)

Tarjeta de red (wire, wireless): 
Las tarjetas de red (también denominadas adaptadores de redtarjetas de interfaz de red o NIC) actúan como la interfaz entre un ordenador y el cable de red. La función de la tarjeta de red es la de preparar, enviar y controlar los datos en la red. 
http://es.kioskea.net/contents/pc/carte-reseau.php3

Dispositivos wireless (2.4, 5.0 GHz):
Los puntos de acceso son dispositivos de red “wireless” que funcionan de forma equivalente a los “hubs” o concentradores, permitiendo que varios clientes “ wireless” se comuniquen entre sí. A menudo se utilizan varios puntos de acceso para cubrir un área determinada como una casa, una oficina u otro tipo de localización delimitada.
Los puntos de acceso poseen típicamente varias conexiones de red: la tarjeta “wireless” y una o más tarjetas Ethernet que se utilizan para comunicarse con el resto de la red.
Los puntos de acceso se pueden comprar como tales pero también se puede configurar un sistema FreeBSD para crear nuestro propio punto de acceso “wireless” utilizando un determinado tipo de tarjetas “wireless” que poseen tales capacidades de configuración. Existe una gran cantidad de fabricantes de hardware que distribuyen puntos de acceso y tarjetas de red “wireless”, aunque las capacidades de unos y otras varín.
http://www.freebsd.org/doc/es/books/handbook/network-wireless.html


cable
El cable es el medio que los PC de una red se pueden comunicar el uno con el otro. Hay distintitos tipos de cables para hacer una red, que siempre esta sujeto a la topología de la red, con esto tendremos que tener en cuenta varios factores.
Estos son los distintos tipos que podemos encontrar en una Lan (Local Area Network, Red de Área Local):
Cable de par trenzado sin apantallar / UTP Unshielded twisted pair
Cable de par trenzado apantallado / STP Shielded twisted pair
Cable coaxial
Cable de fibra óptica
LANs sin cableado 
continuar buscando..........


RJ-45
(registered jack 45) es una interfaz física comúnmente usada para conectar redes de cableado estructurado, (categorías 4, 5, 5e, 6 y 6a). Es parte del Código Federal de Regulaciones de Estados Unidos. Posee ocho pines o conexiones eléctricas, que normalmente se usan como extremos de cables de par trenzado.
http://es.wikipedia.org/wiki/RJ-45

The Network Faceplate
Before you can begin the connection process, you first must locate your network wall jack. Once you've located it, the following cartoon details what the faceplate means and which ports to use.


Network wall Jack
A network jack or Ethernet jack is a type of electrical outlet that allows a computer to be connected to other computers within a network via the network wires. The jack is made up of a plastic box and a receptacle that accepts a standard RJ45 data plug. It provides convenience by allowing a computer to instantly connect or disconnect to a local area network (LAN), thus allowing a computer to be used anywhere there is a network jack. Wiring a network jack might seem to be a complicated task, but it actually is a simple and straightforward one. Learn how to wire a network jack to save the cost of calling a technician.

http://www.ehow.com/how_6756828_wire-network-wall-jack.html


Monday, November 14, 2011

History of computer networks

Before the advent of computer networks that were based upon some type of telecommunications system, communication between calculation machines and early computers was performed by human users by carrying instructions between them. Many of the social behaviors seen in today's Internet were demonstrably present in the 19th century and arguably in even earlier networks using visual signals.
Today, computer networks are the core of modern communication. All modern aspects of the public switched telephone network (PSTN) are computer-controlled, and telephony increasingly runs over the Internet Protocol, although not necessarily the public Internet. The scope of communication has increased significantly in the past decade, and this boom in communications would not have been possible without the progressively advancing computer network. Computer networks, and the technologies needed to connect and communicate through and between them, continue to drive computer hardware, software, and peripherals industries. This expansion is mirrored by growth in the numbers and types of users of networks from the researcher to the home user.

Read more http://en.wikipedia.org/wiki/Computer_network

Classification of Networks by its Scope (Geographic Coverage)

Personal Area Network (PAN): A network of computers used to communicate different devices (computers, internet access points, cell phones, PDAs, audio devices, printers, etc..) Near the access point. The scope of a PAN is typically a few meters and is for personal use. PAN networks can be connected with wires to the computer bus (USB and FireWire). WPAN (Wireless Personal Area Network) can also be made possible with network technologies such as IrDA and Bluetooth.



Local area network (LAN) communications network used to interconnect multiple computers and other devices. Its distribution is limited to a building or a range of 200 meters without using a repeater. Are mostly used to connect personal computers and workstations in the home, offices, factories, etc.. This means that users can share resources or devices that are connected to other equipment such as printers, faxes, file sharing, etc...



Campus Area Network (CAN): CAN is a collection of geographically dispersed LANs within a campus (university, government offices, factories, etc..) belonging to the same entity in a limited area in kilometers. CAN A commonly used technologies such as FDDI, wireless, Gigabit Ethernet, and so on. 







Metropolitan Area Network (MAN): A MAN is a collection of LANs or CANs dispersed in a city NACs (tens of kilometers). A MAN used technologies such as ATM, Frame Relay, xDSL (Digital Subscriber Line), WDM (Wavelength Division Modulation), ISDN, E1/T1, PPP, etc. for connectivity through media such as copper, fiber optic, and microwave.

 





Wide Area Network (WAN): WAN is a collection of geographically dispersed LANs to hundreds of kilometers apart. A network device called a router is able to connect LANs to a WAN. Technologies commonly used ATM (Asynchronous Transfer Mode), Frame Relay, X.25, T1/E1, GSM, TDMA, CDMA, xDSL, PPP, etc. for connectivity through media such as fiber optics, microwave, cellular, satellite, etc..




Storage Area Network (SAN): A network designed to connect servers, arrays (arrays) discs and supporting libraries. It is mainly based on iSCSI or fiber technology. Its function is to connect quickly, securely and reliably various storage elements that comprise it.




Referencias:
Miércoles 13 de octubre 2010, 8:21 P. M.
Miércoles 13 de octubre 2010, 8:21 P. M.
Miércoles 13 de octubre 2010, 9:09 P. M.
Miércoles 13 de octubre 2010, 9:30 P. M.
   

Definition of computer networks

 

The computer network is a set of computers connected by cables, signals, waves or any other method of data transport in order to share information (files, videos, MP3, etc..), Resources (CD-ROM, printers, etc..), services (Internet access, e-mail, chat, games, etc.).


Miércoles 13 de octubre 2010, 8:21 P. M.
Miércoles 13 de octubre 2010, 8:21 P. M.
Miércoles 13 de octubre 2010, 9:09 P. M.
Miércoles 13 de octubre 2010, 9:30 P. M.