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Network Equipment, Basic Knowledge You Need to Get

August 9 2011 , Written by ciscorouterswitch Published on #Cisco Routers

Computer networking devices are units that mediate data in a computer network. Computer networking devices are also called network equipment, Intermediate Systems (IS) or InterWorking Unit (IWU). Units which are the last receiver or generate data are called hosts or data terminal equipment.

 

The Internet has truly revolutionized the way we communicate. If you actually think about it, the Internet is computer networking at the highest scale of complexity. It’s a continuous link of connected computers that spreads worldwide. How is data transfer and the implementation of networking protocols made possible in this colossal network? It is made possible because of networking devices that regulate data traffic over the whole network, providing connectivity and control. The network design is based on the OSI (Open Systems Interconnection) model. Router, switch, hub and bridge are networking devices that act as mediators at various levels of this networking model.

 

What are the differences in the design and functioning of these networking devices: router, switch, hub and bridge?

Every one of these network devices which we compare in the following is a part of every Large Area Network (LAN), Wide Area Network (WAN) or small private networks. They integrate and connect the network at various levels, while providing control over data flow.

 

The main differences in functionality of Router, Switch, Hub and Bridge

A computer network connected to the Internet is designed to be a self-regulating network that can guarantee the transmission of data to right destinations and regulate overall data transfer. The network can be primarily divided into two types of devices which are terminals (connected computers) and control elements or connecting devices. The role router, switch, hub and bridge play in a computing network determines their basic functionality and difference.

 

Two or more computing networks are connected together by a router. It is charged with the responsibility of controlling the inter network data traffic. They are highly intelligent devices with embedded software that are used to control the flow of data packets across diverse networks.

 

A network switch is charged with the job of connecting smaller segments of a single network into a connected whole. They are extensively used in Ethernet local area networks.

 

A hub connects various Ethernet devices to integrate them into a whole network segment. It is one of the most basic hardware devices that connect two or more Ethernet terminals in a network.

 

A network bridge is nothing more than a type of switch. While a switch has multiple connection ports, a bridge has a single connection port. In the next section, let us have a look at the features of each one of these devices in more detail.

 

Referring to OSI model layers, a router is functional on the network layer of the OSI model, which is also known as level 3. They integrate logical subnet together and their operation is made possible by inbuilt operating systems. They are designed to calculate the best possible path for transmission of data packets between networks. The basis for routing of data through a router is the use of Internet protocol addresses. You might want to check out the OSI model diagram to understand the functions of these devices better.

 

Network switches are functional on the layer 2 of the OSI model. This layer is often referred to as the data link layer. Network switches transfer data across a network segment using MAC addresses for reference.

 

A hub operates only at layer 1 level of OSI model, which is the physical layer. Integrating Ethernet terminals together is its only function and it is a passive device used for data transfer. A bridge is just a type of network switch that connects two network segments together. Like switches, they too operate at the data link layer.

 

All these networking devices provide connectivity and help regulate Internet traffic through local and global Internet networks. Tips of identifying what are main networking hardware help you know the role and function of router, switch, hub and bridge in a network. So which network equipment you select depends on what you need in your home network or business network.

 

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Common basic networking devices:

Router: a specialized network device that determines the next network point to which it can forward a data packet towards the destination of the packet. Unlike a gateway, it cannot interface different protocols. Works on OSI layer 3.

 

Bridge: a device that connects multiple network segments along the data link layer. Works on OSI layer 2.

 

Switch: a device that allocates traffic from one network segment to certain lines (intended destination(s)) which connect the segment to another network segment. So unlike a hub a switch splits the network traffic and sends it to different destinations rather than to all systems on the network. Works on OSI layer 2.

 

Hub: connects multiple Ethernet segments together making them act as a single segment. When using a hub, every attached all the objects, compared to switches, which provide a dedicated connection between individual nodes. Works on OSI layer 1.

   

Repeater: device to amplify or regenerate digital signals received while sending them from one part of a network into another. Works on OSI layer 1.

 

Some hybrid network devices:

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 transmissions, such as asynchronous and synchronous transmissions.

   

Bridge Router (B router): CombineS router and bridge functionality and are therefore working on OSI layers 2 and 3.

 

Hardware or software components that typically sit on the connection point of different networks, e.g. between an internal network and an external network:

 

Proxy: 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: network service provide as hardware or software that converts internal to external network addresses and vice versa

 

Other hardware for establishing networks or dial-up connections:

Multiplexer: device that combines several electrical signals into a single signal

   

Network Card: a piece of computer hardware to allow the attached computer to communicate by 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, as a computer communicating with another computer over the telephone network

   

ISDN terminal adapter (TA): a specialized gateway for ISDN

   

Line Driver: a device to increase transmission distance by amplifying the signal. Base-band networks only.

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