WHAT ARE THE DIFFERENT NETWORK DEVICES?

 

NETWORK DEVICES

 

What does a Network Device mean?

Network devices, or networking hardware, are physical devices that are required for communication and interaction between hardware on a computer network.

 

EXAMPLES OF NETWORK DEVICE

·         Hub

·         Switch

·         Router

·         Bridge

·         Modem

·         Transceivers

·         Firewall

HUB

A hub is a simple device that directs data packets to all devices connected to it. Basically, a hub does nothing except provide a pathway for the electrical signals and regenerate signal before it forwards it to all connected devices. It can be used with both digital and analog data, provided its settings have been configured to prepare for the formatting of the incoming data. For example, if the incoming data is in digital format, the hub must pass it on as packets; however, if the incoming data is analog, then the hub passes it on in signal form.        

  

  In a hub, a message is passed along or "broadcast" to every one of its ports. It does not matter that the message is only destined for one port. The hub has no way of distinguishing which port a message should be sent to. Passing it along to every port ensures that it will reach its intended destination. This places a lot of traffic on the network and can lead to poor network response times.

 

 

 

THE SWITCH

Similar to hubs, switches are the connectivity point of a wired network. Devices are connected via twisted-pair cabling, one for each device. The difference between two is in how the devices deal with the data that they receive. Switches generally have a more intelligent role than hubs. A switch is a multiport device that improves network efficiency. 

The switch maintains limited routing information about nodes in the internal network, and it allows connections to systems like hubs or routers. Strands of LANs are usually connected using switches. Generally, switches can read the hardware addresses of incoming packets to transmit them to the appropriate destination. Using switches improves network efficiency over hubs or routers because of the virtual circuit capability. Switches also improve network security because the virtual circuits are more difficult to examine with network monitors. You can think of a switch as a device that has some of the best capabilities of routers and hubs combined.

THE ROUTER

Routers are completely different devices. If a hub or switch is concerned with transmitting frames, the job of a router, as its name implies is to route packets to other networks until that packet ultimately reaches its destination. It can transmit through wired and wireless networks.

A router is typically connected to at least two networks, commonly two Local Area Networks (LANs) or Wide Area Networks (WANs) or a LAN and its Internet Service Provider's network.

Routers help transmit packets to their destinations by charting a path through the sea of interconnected networking devices using different network topologies. Routers are intelligent devices, and they store information about the networks they’re connected to. Most routers can be configured to operate as packet-filtering firewalls and use access control lists (ACLs). 

OTHER NETWORK DEVICES

THE BRIDGE 

  A Bridge is used to divide larger networks into smaller sections. It is located between two physical network segments and manages the flow of data between the two. By looking at the physical address of the devices connected to each segment, bridges can forward the data if the destination address is on another interface, or block it from crossing if verified that it is on the interface from which it came.

 

Bridges work only at the Physical and Data Link layers of the OSI model. Bridges are used to divide larger networks into smaller sections by sitting between two physical network segments and managing the flow of data between the two.

Types of Bridges

1. Transparent Bridge - derives its name from the fact that the devices on the network are unaware of its existence. This bridge does nothing except block or forward data based on the  MAC address.

 

2. Source route bridge - is used in Token Ring networks. The source route bridge derives its name from the fact that the entire path to be taken by the packet through the network is embedded within the packet.

 

3. Translational bridge - is used to convert one networking data format to another; for example, from Token Ring to Ethernet, and vice versa.

 

THE NETWORK CARD

A Network Card, also called the Network Interface Card, is a device that enable computers to connect to the network.

To install or configure a network interface, you will need drivers of the device. You might also need to configure it, although many devices are now plug and play. Most network cards are now software configured. Many of these software configuration utilities also include testing capabilities. The drivers and software configuration utilities supplied with the cards are often not the latest available, so it is best practice to log on to the internet and download the latest drivers and associated software.

THE MODEM

 A Modem, short for modulator/

demodulator, is a device that converts the digital signals generated by a computer into analog signals that can travel over conventional phone lines.

The modem converts the signal back at the receiving end. It converts it into a format the computer can understand. A modem can be used as a means to connect to an ISP, or as a mechanism for dialing up to a LAN. A modem can also be internal add-in expansion cards or external devices that connect to the serial or USB port of a system. It can also be PCMCIA cards designed for use in laptops, or proprietary devices designed for use on other devices such as portables and handhelds.

 

 The receiving modem performs the reverse transformation and provides a digital output to a device connected to a modem, usually a computer. The digital data is usually transferred to or from the modem over a serial line through an industry standard interface, RS-232. Many telephone companies offer DSL services, and many cable operators use modems as end terminals for identification and recognition of home and personal users. Modems work on both the Physical and Data Link layers.

TRANSCEIVERS

The Transceiver is responsible for placing signals onto the network media and detecting incoming signals travelling through the same wire.

 

In terms of networking, transceivers can be shipped as a module or chip type.

> Chip transceivers are small and are inserted into a system board or wired directly on a circuit board.

> Module transceivers are external to the network and are installed and function similar to other computer peripherals or they can also function as stand-alone devices.

Several Types of the transceivers are RF transceivers, fiber optic transceivers, Ethernet transceivers, wireless (WAP) transceivers, and more. Each of these media types are different though the function of the transceivers remains the same. Each type of the transceivers used has different characteristics, such as the number of ports available to connect to the network and whether it functions as a full-duplex communication if supported.

 

 

FIREWALL

A firewall is a networking device that can be either hardware or software-based. It controls access to your organization's network. This controlled access is designed to protect data and resources from outside threat.     

           

A typical firewall is placed at entry/exit points of a network. For example, placing a firewall between an internal network and the internet. When in place, it can control  access in and out of that point. The firewall is configured on the server to allow or permit certain types of network traffic. In small offices and in regular home use, a firewall is commonly installed on the local system and configured to control traffic.