WHAT ARE THE DIFFERENT NETWROK DEVICES?

Network Devices

Hardware devices that are use to connect computers, printers, fax machines and other electronic devices to a network are called network devices. These devices transfer data in a fast, secure and correct way over same or different network. Network devices may be inter-network or intra-network.

It can transmit and receive wireless HART  data and perform the basic functions necessary to support network formation and maintenance. Network devices include field devices, router devices, gateway devices, and mesh hand-held devices.

Need for Computer Networking. Computer Networks help users on the network to share the resource and in communication... File sharing: Networking of computers helps the network users to share data files. Hardware sharing: Users can share devices such as printers, scanner, CD-ROM drives, hard drives etc.

Types of Network Devices:

Hub

A hub is a physical layer networking device  which is used to connect multiple devices in a network. A hub is a simple device that directs data packets to all devices connected to it. They are generally used to connect computers in a LAN. 

A hub has many ports in it. A computer which intends to be connected to the network is plugged in to one of these ports. In a hub, a message is passed along or broadcast to every one of its ports. It receives a packet of data (an Ethernet frame) at one of its ports from network devices, it transmit (repeats) the packet to all of its ports to all of the other network devices... Hubs operate in such a way that all data received through one pot is sent to all ports. 

Switch

Similar to hubs, switches are the connectivity point of a wired network. A switch is a data link layer networking device which connect devices in a network and used packets switching to send and receive data over the network.

Like hub, a switch also has many ports, to which computers are plugged in. If a hub forwards the data it receives to all ports on the device, a switch forwards the data it receives only to port that connects to the destination. However when a data frame arrives at any port of a network switch, it examines the destination address and sends the frame to the corresponding device(s). Thus, it supports both unicast and multicast communications.

Router

Routers are completely different devices.  A router acts as a dispatcher, choosing the best route for your information to travel. It connects your business to the world, protect information from security threats, and can even decide which computers get priority over others.

If a hub or switch is concerned with transmitting frames, the job of a router, as its name implies, is to route to other networks until that packet ultimately reaches its destination. A router helps you connect multiple devices to the Internet, and connect the devices to each. Also, you can use routers to create local network of devices.  It can transmit through wired and wireless networks. These local networks are useful if you want to share files among devices or allow employees to share software tools.

Network Bridge

A bridge is used to divide larger networks into smaller sections. A network bridge is a computer networking device that creates a single aggregate network from multiple communication networks or network segments. This function is called network bridging. 

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 Bridges:

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 address.

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.

Translation 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 controller (NIC, also known as a network interface card, network adapter, LAN adapter or physical network interface, and by similar terms) is a device that enables computer 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 networking cards are now software configured. Early network interface controllers were commonly implemented on expansion cards that plugged into a computer bus. 

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 and that is used especially to transmit and receive information between computer via landlines.

It is a hardware component that allows a computer or another device, such as a router or switch, to connect to the internet. The modem converts the signal back at the receiving end. It coverts 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. Dial up modem also required full use of the local telephone line. meaning voice calls would interrupt the internet connection.

Transceivers

The Transceiver is responsible for placing signals onto the network media and detecting incoming signals traveling through the same wire. In a network environment, a transceiver gets its name from being both a transmitter and a receiver of signals, such as analog or digital.

The term transceiver does describe a separate network device, but it can also be technology built and embedded in devices such as network cards and modem. Technically. on a LAN the transceiver is responsible to place signals onto the network media and also detecting incoming signals traveling through the same cable. 

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.

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Routers, hubs and switches are network device terms that tend to be used interchangeably. The functions of the three devices are quite different from another, even though at times, they are all integrated into a single device,

Each device serves as a central connection for all of your network equipment and handles a data type known as frames. A frame carries your data. when a frame is received, it is amplified, and then transmitted on to the port of destination PC. The big big difference between frames is in the method in which frames are being delivered.

Networking has many components that make it work efficiently. Devices, when combined, will enable a faster transmission of data.

WHAT ARE THE TYPES OF NETWORK TOPOLOGY

Network Topology 

Network topology refers to the layout or structure of the network in relation with the flow of data. Can be used to define or describe the arrangement of various types of telecommunication network, including command and control radio networks, industrial field busses and computer networks. It is a substantial arrangement of a network in which all nodes are connected with each other using network link or connecting lines. Apart from just describing how he nodes are interconnected, network topology also explains how the data is transferred in a network. And may be depicted physically or logically.

Howard Frank had founded Network Analysis Corporation (NAC), a company specializing in topological design based on hid groundbreaking work at the Office of Emergency Preparedness (OEP). Frank remembers Robert's call requesting a meeting: Arpanet was a four node network

Physical Topology refers to the interconnected structure structure of a local area network (LAN). The method employed to connect the physical devices on the network with the cables, and the type of cabling used, all constitute the physical topology.

Logical Topology is a concept in networking that defines the architecture of communication mechanism for all nodes in a network. Using network equipment such as routes and switches, the logical topology of a network can be dynamically maintained and reconfigured.

Types of Network Topologies:

Linear Bus Topology

Linear bus topology is a type of network topology where each device connects one after the other in a sequential chain (shown right). In this case, the bus is the network connection between the devices. It uses a long cable, referred to as a backbone, to which computers and other devices attached. If any link in the network chain is severed, all transmission is halted.

Advantages of Linear Bus Topology:

👍 It is the easiest network topology for connecting             peripherals or computer in a linear fashion.

👍 It works very efficient well when there is a small           network.

👍 It requires less cable length than the star topology.

👍 It is easy to connect or remove devices in this network       without affecting any other devices.

👍 Very cost-effective as compared to the other network         topology i.e. mesh and star

Disadvantages of Linear Bus Topology:

👎 Bus topology is not great for large network.

👎 Identification of problem becomes difficult if whole         network goes down.

👎 The entire network shuts down if there is a break in the     backbone.

👎 Need of terminators are required at both ends of main         cable.

👎 This network topology is very slow as compared to other       topologies.

Bus topology is one of the simplest physical topology used for the network. This topology is famously used for Local Area Network.  Small workgroup whose computers are connected using thinnest cable. Trunk cables connecting hubs or switches of department LANs to form a larger LAN.

Star Topology

Star topology is one of the most common network setups. In this configuration, every node connects to a central network device, like a hub, switch, or computer. The central network device acts as a server and the peripheral devices acts as clients. Data from the computer passes through the hub or switch before it can reach the other target node.

Advantages of Star Topology:

👍 Easy to install and wire.

👍 No disruptions to the network when connecting or removing     devices

👍 Easy to detect faults and to remove parts.

👍 Centralize management of the network, through the use of     central computer, hub, or switch.

👍 It provides very high speed data transfer.

Disadvantages of Star Topology:

👎 Entire performance of the network depends on the single       device hub.

👎 If the hub device goes down, the entire network will be       dead.

👎 Requires more wires compared to the ring and bus topology.

👎 Purchasing the network cabling and file servers can be       expensive.

👎 Viruses can spread to other computers throughout a           computer network.

Stark network topologies are common in home networks, where the central connection point may be a router, switch or networking hub. Unshielded Twisted Pair (UTP) Ethernet cabling is typically used to connected devices to the hub, though coaxial cable or optical fiber may also be employed.

Ring Topology

Ring topology is a network configuration where device
connections create circular data path. Wherein nodes are connected to each other forming one contiguous pathway in a ring formation. In other words, data need to travel from one node to the next, with each one receiving data traffic and passing it along to the next until it reaches its final destination.

Advantages of Ring Topology:

👍 All data flows in one direction, reducing the packet         chance of packet collisions.

👍 Each repeater duplicates the data signals so that there       is a very little signal degradation.

👍 A network server is not needed to control network             connectivity between each workstation.

👍 Data can transfer between workstations at high speed.

👍 Additional workstations can be added without impacting       performance of the network.

Disadvantages of Ring Topology:

👎 All data being transferred over the network must pass         through each workstation on the network, which can make       it slower than a star topology.

👎 The entire network will be impacted if one workstation       shuts down.

👎 It is expensive.

👎 Difficult to troubleshoot the ring.

👎 Addition and removal of any node during a network is         difficult and may cause issue in network activity.

Ring topology are most often found on school campuses, though some commercial organizations also use them. FDDI, SONET, or Token Ring technology are typically used. In Wide Area Networks (WAN) and Metropolitan Area Networks (MAN), a ring topology is used to as the topology for the backbone connect the costumers.

Mesh Topology

Mesh topology is a network setup where each computer and network device is interconnected with another. This network are structures wherein all the nodes on the network can route data traffic on their one. This topology setup allows for most transmission to be distributed even if one of the connections goes down. Has multiple connections, making it the most fault tolerant topology available.

Advantages of Mesh Topology:

👍 Manages high amounts of traffic, because multiple devices     can transmit data simultaneously.

👍 A failure of one device does not cause a break in the         network or transmission of data.

👍 Adding additional devices dost not disrupt data               transmission between other devices.

👍 Fault identification is easy because of point to point       connection.

👍 It provides high privacy and security.

Disadvantages of Mesh Topology:

👎 Requires high NO: of cables and I/o ports for                 communication.

👎 Installation is very difficult in mesh topology, as each     node is connected to every node.

👎 Mesh topology is costly compared to other network             topologies

👎 The chance of redundant connections is high, which adds       to the high costs and potential for reduced efficiency.

👎 Building and maintaining the topology is difficult and       time consuming

Mesh topology is a type of networking where all nodes cooperate to distribute data amongst each other. This topology was originally develop 30+ years ago for military applications, but today, they are typically used for things like home automation, smart HVAC control, and smart buildings.

Hybrid Topology

Hybrid  topology is a type network topology  that uses two or

more differing network topologies in such way the final network does not exhibit one of the characteristics of the standard topologies. This combination of topologies is done according to the requirements of the organization. Good examples of a hybrid network are star-ring and star-bus network.

Advantages of Hybrid Topology:

👍 Hybrid network combines he benefits of different types of     topologies.

👍 Can modified as per requirement. 

👍 It is extremely flexible.

👍 It is very reliable.

👍 It is easily scalable.

Disadvantages of Hybrid Topology:

👎 The design of a hybrid network is complex.

👎 It is expensive.

👎 Hardware changes are required in order to connect             topology to another topology.

👎 Installation is a difficult process.

👎 Hubs which are use to connect two distinct network, are       very costly. And hubs are different from usual hubs as       they need to be intelligent enough to work with different     architectures.

If there is a Mesh topology in one office department while a Ring topology is another department, connecting these two with bus topology will result in Hybrid topology. The choice to use hybrid topology over a standard topology depends on the need of a business, school, or the users.