WHAT ARE THE DIFFERENT NETWORK DEVICES

  

Dominican College of Tarlac

Mac Arthur Highway, Poblacion (Sto. Rosario), Poblacion (Sto. Rosario), Capas, 2315 Tarlac, Philippines

Tel No. (045) 491-7579/ Telefax (045) 925-0519

E-mail: domct_2315@yahoo.com

⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼⎼

Information and Communications Technology

NETWORK DEVICES

Network devices, also known as network equipment or networking hardware, are electronic devices which are required for communication and interaction between devices on a computer network. Specifically, they mediate data transmission in a computer network. 

HUB

A hub is a simple device that directs data packet to all devices connected to it. Basically, it provides a pathway for the electrical signals and regenerate signal before it forwards it to all connected devices. 

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. It 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. 

Additionally, a 10/100Mbps hub must share it bandwidth or its data transfer rate with each and every one of its ports. So when only one PC is broadcasting, it will have access to the maximum available bandwidth. However, if multiple PCs are broadcasting, that bandwidth will need to be divided among all of those systems, which will degrade performance. 

For today’s high-demand network applications, something with a little more intelligence is required. That is where switches come in.

SWITCH

Similar to hubs, switches are the connectivity point of a wired network. Devices are connected via twisted-pair cabling, one cable for each device. The difference between the two is how the devices deal with what data they receive. 

If a hub forwards the data it receives to all ports on the device, a switch forwards the data it receives only to the port that connects to the destination device. 

A switch keeps a record of the MAC addresses or the unique identity of the client devices connected to it. With this information stored in a switch, it can identify which system is sitting on which port. Thus, when a message is received, it knows exactly which port to send to. This significantly increases the network response times. 
To differentiate from a hub, a 10/100 Mbps switch will allocate a full 10/100Mbps to each of its ports. So it does not matter how many PCs are transmitting, user will always have access to the maximum amount of bandwidth. It is for these reasons why a switch is considered to be “smarter” and a much better choice than a hub. 

The network result of these measures is that switches can offer significant performance improvements over hub-based networks, particularly when the network use is high. 

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 Network (WANs) or a LAN and its Internet Service Provider’s network.

Routers have a WAN port that connects to an Internet connection provided by your Internet Service Provider, the integrated switch allows user to easily create a LAN. This allows all the PCs on the LAN to have access to the Internet, Windows files, and printer sharing services. Routers might have a single WAN port and a single LAN port that are designed to connect an existing LAN hub or switch to a WAN. Switches and hubs can be connected to a router with multiple PC ports to expand a LAN.

When a router receives a packet of data, it reads the header of the packet to determine the destination address. Once it has determined the address, it looks in its routing table to determine whether it knows how to reach the destination; if it does, it forwards the packet to the next hop on the route. The next hop might be the final destination or it might be another router.

MODEM

A modem, short for modulator or 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. It 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 for 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 a portable and handhelds. 

NETWORK BRIDGE

A network 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.

Types of Network Bridge

1. Transparent bridge – derives its name from the fact that the devices on the network are unaware of its existence. A transparent bridge does nothing except block or forward data based on the MAC’s 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. 

NETWORK INTERFACE CARD

A Network Interface Card is a device that enables 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 no the latest available, so it is best to practice to log on to the Internet and download the latest the latest drivers and associated software. 

TRANCEIVER

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

The term transceiver does not describe a separate network device, but it can also be technology built and embedded in devices such as network cards and modems. In a network environment, a transceiver gets its name from being both a transmitter and a receiver of signal.

Given the description of the function of a transceiver, it is logical that the technology would be found in network cards. Although transceivers are found in network cards, they can be external devices as well. 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 externals to the network and are installed and function similar to the 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 transceiver remains the same. Each type of the transceiver 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 protects data and resources outside threats. 

A typical firewall is placed at entry or exits 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.

Hardware firewalls are used in networks of all sizes today. Hardware firewalls are often dedicated network devices that can be implemented with very little configuration and protect all systems behind the firewall from outside sources. These are readily available and often combined with other devices nowadays. For example, many broadband routers and wireless access points have built-in firewall functionality. In such case, the router or WAP might have a number of ports available to plug systems into.

REVIEW: NETWORK DEVICES

Hubs – These are simple devices that direct data packet to all devices connected to it.

Switch – It forwards the data it receives only to the port that connects to the destination device. 

Router – It routes packets to other networks until that packet ultimately reaches its destination.

Modem – A device that converts the digital signals generated by a computer into an analog signals that can travel over conventional phone lines.

Network Bridge – Divides networks to reduce overall traffic. It has three types – transparent bridge, source route bridge, and translational bridge.

Network Interface Card – enables systems to connect to the network. 

Transceiver – Responsible for placing signals onto the network media and detecting incoming signals traveling through the same wire.

Firewall – Provides controlled data access between networks.  

Blog by 

Candice Kate S. Hipolito

10 - St. Dominic