Transmission Media - Transmission media are the facilities used to interconnect computers in a network, such as twisted-pair wire, coaxial cable, and optical fiber cable. Transmission media are sometimes called channels, links or lines.
Shared data - Shared data are data that file servers provide to clients such as data files, printer access programs and e-mail.
Shared printers and other peripherals - Shared printers and peripherals are hardware resources provided to the users of the network by servers. Resources provided include data files, printers, software, or any other items used by clients on the network.
Network Interface Card -
Each computer in a network has a special expansion card called a network interface card (NIC). The NIC prepares(formats) and sends data, receives data, and controls data flow between the computer and the network. On the transmit side, the NIC passes frames of data on to the physical layer, which transmits the data to the physical link. On the receiver's side, the NIC processes bits received from the physical layer and processes the message based on its contents.
Each computer in a network has a special expansion card called a network interface card (NIC). The NIC prepares(formats) and sends data, receives data, and controls data flow between the computer and the network. On the transmit side, the NIC passes frames of data on to the physical layer, which transmits the data to the physical link. On the receiver's side, the NIC processes bits received from the physical layer and processes the message based on its contents.
Hub - Hub is a device that splits a network connection into multiple computers. It is like a distribution center. When a computer requests information from a network or a specific computer, it sends the request to the hub through a cable. The hub will receive the request and transmit it to the entire network. Each computer in the network should then figure out whether the broadcast data is for them or not.
Switch -
Switch is a telecommunication device grouped as one of computer network components. Switch is like a Hub but built in with advanced features. It uses physical device addresses in each incoming messages so that it can deliver the message to the right destination or port.
Like a hub, switch doesn't broadcast the received message to entire network, rather before sending it checks to which system or port should the message be sent. In other words, switch connects the source and destination directly which increases the speed of the network. Both switch and hub have common features: Multiple RJ-45 ports, power supply and connection lights.
Switch is a telecommunication device grouped as one of computer network components. Switch is like a Hub but built in with advanced features. It uses physical device addresses in each incoming messages so that it can deliver the message to the right destination or port.
Like a hub, switch doesn't broadcast the received message to entire network, rather before sending it checks to which system or port should the message be sent. In other words, switch connects the source and destination directly which increases the speed of the network. Both switch and hub have common features: Multiple RJ-45 ports, power supply and connection lights.
Network Component : Softwares
Local Operating System - A local operating system allows personal computers to access files, print to a local printer, and have and use one or more disk and CD drives that are located on the computer. Examples are MS-DOS, Unix, Linux, Windows 2000, Windows 98, Windows XP etc.
Network Operating System - The network operating system is a program that runs on computers and servers, and allows the computers to communicate over the network.
Servers - Servers are computers that hold shared files, programs, and the network operating system. Servers provide access to network resources to all the users of the network. There are many different kinds of servers, and one server can provide several functions. For example, there are file servers, print servers, mail servers, communication servers, database servers, fax servers and web servers, to name a few.
Clients - Clients are computers that access and use the network and shared network resources. Client computers are basically the customers(users) of the network, as they request and receive services from the servers.
Network Components : Network Hardware Devices
Gateway: this device is placed at a network node and interfaces with another network that uses different protocols. It works on OSI layers 4 to 7.
Router: a specialized network device that determines the next network point to which it can forward a data packet towards the ultimate destination of the packet. Unlike a gateway, it cannot interface different protocols. It works on OSI layer 3.
Switch: a device that allocates traffic from one network segment to certain lines (intended destination(s)) which connect the segment to another network segment. Unlike a hub, a switch splits the network traffic and sends it to different destinations rather than to all systems on the network. It works on OSI layer 2.
Bridge: a device that connects multiple network segments along the data link layer. It works on OSI layer 2.
Hub: a device that connects multiple Ethernet segments, making them act as a single segment. When using a hub, every attached device shares the same broadcast domain and the same collision domain. Therefore, only one computer connected to the hub is able to transmit at a time.
Depending on the network topology, the hub provides a basic level 1 OSI model connection among the network objects (workstations, servers, etc.). It provides bandwidth which is shared among all the objects, in contrast to switches, which provide a connection between individual nodes. It works on OSI layer 1.
Repeater: a device which amplifies or regenerates digital signals received while sending them from one part of a network into another. It works on OSI layer 1.
Hybrid network devices include:
- Multilayer switch: a switch which, in addition to switching on OSI layer 2, provides functionality at higher protocol layers.
- Protocol converter: a hardware device that converts between two different types of transmission, such as asynchronous and synchronous transmissions.
- Bridge router (brouter): a device that combines router and bridge functionality and therefore works on OSI layers 2 and 3.
Hardware or software components which typically sit on the connection point of different networks (for example, between an internal network and an external network) include: - Proxy server: computer network service which allows clients to make indirect network connections to other network services.
- Firewall: a piece of hardware or software put on the network to prevent some communications forbidden by the network policy.
- Network address translator (NAT): network service (provided as hardware or as software) that converts internal to external network addresses and vice versa.
Other hardware devices used for establishing networks or dial-up connections include:
- Multiplexer: a device that combines several electrical signals into a single signal.
- Network interface controller (NIC): a device connecting a computer to a wire-based computer network.
- Wireless network interface controller: a device connecting the attached computer to a radio-based computer network.
- Modem: device that modulates an analog "carrier" signal (such as sound) to encode digital information, and that also demodulates such a carrier signal to decode the transmitted information. Used (for example) when a computer communicates with another computer over a telephone network.
- ISDN terminal adapter (TA): a specialized gateway for ISDN.
- Line driver: a device to increase transmission distance by amplifying the signal; used in base-band networks only.
What are the software components of a Network?
The software components of a LAN can be grouped into two categories:
1. Inside PCs/workstations and servers
- NIC Drivers
- Network Operating System for servers, for example, Novell® Netware 4.1 or Microsoft Windows® NT
- Network Operating System for clients (PCs/workstations), for example, Novell® Netware 4.1 client or Microsoft Windows® 95
- Networking protocol software, for example, TCP/IP, Novell® IPX
- Application software, for example, emails, Internet Web Browser
- Network Management Software, for example, Simple Network Management Protocol (SNMP), Remote Network Monitoring (RMC)
- Forwarding/routing & control software, for examples, transparent bridging, spanning tree and IP routing software
