What is Network Devices ?

Network Devices are the component that are used to interconnect multiple computing device to form a network in order to share files or resources for communication.

Types of Networking Device:-
  • Hub
  • Switch
  • Router
  • Modem 
  • Bridge
  • NIC
  • Gateway
  • Repeater
  • It is a device used to connect multiple computers as a single LAN Network.
  • Generally hub's are available with 4,8,12,24,48 Ports.
  • Hub's are used in networks that use twisted pair cabling to connect multiple devices coming from different branches.
  • Hub's are simple device that direct data packets to all devices connected to the hub. And Hub cannot filter data.
  • It use Physical Layer Protocol.
  • Current Hub typically share bandwidth between all the ports.
Hub Are of 3 Types
  • Passive Hub:-These only serve as paths or passage for data passing from one device to another. Passive Hub neither regenerates any signal nor amplifies. And it does not require Electricity to work.
  • Active Hub:-It is same as like passive Hub but in addition before forwarding it will improve the quality of signal  by amplifying it. Active Hub regenerates our signals. And it need electricity to work.
  • Intelligent Hub:-It works like active hub and includes remote management capabilities. This helps the administrator to monitor network traffic passing through the hub and you can configure each port on it individually, It also known as a manageable hub.
Advantages of Hub
  • Comparing to switches, hubs are really In expensive and easy to install.
  • Hubs can connect different types of media all at once with a central hub.
  • Extends maximum distance between node pairs.
  • Hubs rarely affects the network because it operates using a broadcast model.
Disadvantages of Hub
  • Hubs cannot provide dedicated bandwidth for every device.
  • Data transmission speed becomes low.
  • It creates unnecessary traffic between computing devices.
  • Hubs cannot communicate fully duplex mode, it can only operate in half-duplex mode.
  • It increases more chances of collision in between domains.
  • High Security Concern.(i.e. Data is shared between all devices)
  • It is a multiport bridge with a buffer and a design that can boost its efficiency and performance.
  • The switch can perform error checking before forwarding data. And it does not forward packets that have errors and forward good packets selectively to the correct port only.
  • A switch is a data link layer device.
  • It is typically used to connect hosts, not LAN's.
  • Switch allows full duplex Ethernet.
  • Switches keep track of the MAC addresses of all connected devices.
Advantages of Switch
  • Switches can be connected directly to workstations.
  • It will increase the performance of the network.
  • They increase the available bandwidth of the network.
  • They help in reducing workload on individual host PCs.
  • If we will use switches in our network then it have less frame collision.
  • Low Security Concern(i.e. Data is shared between only particular device)
Disadvantages of Switch
  • Proper design and configuration is needed in order to handle multicast packets.
  • If switches are in promiscuous mode, they are vulnerable to security attacks.
  • They are more expensive compared to network bridges.
  • Network connectivity issues are difficult to be traced through the network switch.
  • It is a device used to connect to different computing devices and also used to divide a large network into smaller segments.
  • A bridge operates at the data link layer.
  • A bridge is a repeater, with add on the functionality of filtering  content by reading the MAC addresses of source and destination.
  • Bridge reduce the amount of traffic on a LAN by dividing it into two segments.
  • Bridge have memory buffers to queue packets.
  • It provides features like plug-and-play, self configuring.
There are 3 types of Bridge
  • Transparent Bridge:-Transparent Bridges is invisible to the other devices on the network. Transparent Bridge only perform the function of blocking or forwarding data based on MAC address.
  • Translational Bridge:-Translational Bridges are useful to connect segments running at different speeds or using different protocols such as token ring and Ethernet networks. Depending on the direction of travel, a Translational Bridge can add or remove information and fields from frame as needed.
  • Source Routing Bridges:-In Source routing bridge operation is performed by the source station and the frame specifies which route to follow. The host can discover the frame by sending a special frame called the discovery frame, which spreads through the entire network using all possible paths to the destination.
Advantages of Bridge
  • Sometimes Bridge act as repeaters to extend a network. Network with different architecture can be connected together using bridges.
  • Bridges increases bandwidth. Few of the nodes present on a network share a separate collision domain. For these individuals nodes it increases bandwidth.
  • Network reliability is basically high in a bridge which makes it easier to maintain the network. and also network congestion can be reduced by dividing LAN into small segments.
  • Bridges generally functions at the MAC layer. This makes higher levels of protocol transparent.
Disadvantages of Bridge
  • On average a bridge costs more than the hub and repeaters. It is only preferred when there is LAN network traffic load.
  • Bridges cannot individually filter the broadcast traffic. They simply forward broadcast packets.
  • A bridge does more buffering of frames and introduce more relays. This makes them slower compare to a repeater.
  • Bridges make extra processing by viewing all of the MAC addresses, they can potentially downgrade network performance.
  • It is a device that is used to connect with internet using telephone lines.
  • Modem stands for Modulators-demodulators and it is used to transmit digital signals over analog telephone lines.
  • It converts digital signals to analog signals and analog signals to digital signals.
  • Conversion of one type of signal to another is called Modulation And their reconversion to the original type is called demodulation.
  • when an analog facility is used for data communication between two digital devices called Data Terminal Equipment(DTE), Modems are used at each end. DTE can be a terminal or a computer.
  • A modem is a part of the data link layer.
Functions of Modem
  • Data compression:-Data compression method helps to reduce the size of signals, which are required for sending data.
  • Error Correction:-In the error correction techniques, all devices monitor all the information while receiving is undamaged. It splits all the information into small units that is called the frames. In this process, it tags all frames along with checksums, but it is done before sending information. If this information matches with checksums then device grabs the verified information. That is sent by error-correcting modem. But , if it gets to fail in matching with checksum then information is moved back.
  • Flow Control:-Each modem has different speed of sending signals. So in the flow control technique, slower one signals the faster one to pause, by sending a character. If slow device will try to send character to faster modem, then this character would be a signal to the faster modem for pausing the information transfer until the slow modem gets caught up.
  • Helps to provide security while line overloading and other issues.
Types of Modem
There are different types of modem which are used in computer networking. But basically we consider only three types these are Dial-up modem, Cable modem, DSL Modem.
  • Dial-up Modem:-Dial-up modems transmits analog signal via telephone lines. This modem is used mostly to make connection with ISP using of analog signals. Dial-up modem has two variant like as external or internal modem
  • Cable Modem:-A cable modem is a hardware device that allows your computer to communicate with an Internet Service Provider over a landline connection. It converts an analog signal to a digital signal for the purpose of granting access to broadband Internet.
  • DSL Modem:-DSL stands for "Digital Subscriber Line" and it is also known as Broadband Modem. DSL modems offer broadband services for using of different types of internet connections. DSL modems are comfortable for higher internet speed.
Advantages of Modem
  • More useful in connecting LAN with the internet.
  • Speed depends on the cost.
  • A modem is most probably widely used in data communication roadway.
  • A modem converts that the digital signal into an analog signal.
  • Some of the modems are completely compatible with the fax technology. Fax messages can be instantly send and receive using modems.
Disadvantages of Modem
  • No traffic Maintenance is present.
  • Modem those are of Dial-up types requires telephone lines to access the internet. Once the line is disconnected, there won't be any internet access.
  • One major drawback of connecting a modem is that it can make your computer vulnerable to hackers and malwares. however for countering this most modems and routers are included with built in firewalls.
5.NIC (Network Interface Card)
  • Network Interface card is a network adapter that is used to connect the computer to the network. It is installed in the computer to establish a LAN.
  • It has a unique ID that is written on the chip, and it has a connector to connect the cable to it. The cable acts as an interface between the computer and router or modem.
  • NIC allows both wired and wireless communications.
  • NIC is both a physical layer and a data link layer device, i.e. it provides the necessary hardware circuit so that the physical layer processes and some data link layer processes can run on it.
Types of NIC Cards
  • Internal Network Cards:-In internal network cards, motherboard has a slot for the network card where it can be inserted. It requires network cables to provide network access. Internal network cards are of two types. The first type uses Peripheral component Interconnect(PCI) connection, while the second type uses Industry Standard Architecture(ISA).
  • External Network Cards:-In desktop and laptops that do not have an internal NIC, external NICs are used External network cards are of two types: Wireless and USB based. Wireless network card needs to be inserted into the motherboard, however no network cable is required to connect to the network. They are useful while travelling or accessing a wireless signal.
Advantages of NIC
  • Bulk data can be shared among many users.
  • Many peripheral devices can be connected using many ports of NIC cards.
  • The communication speed using the internet is high usually in Gigabytes.
  • The information move is exceptionally dependable among the hubs.
Disadvantages of NIC
  • Data is unsecured.
  • To make fine correspondence the arrangement should be exact.
  • When wired links are use in Network interface card transportability isn't economical and cause inconveniences.
  • A Router is a device like a switch that routes data packets based on their IP addresses.
  • For this router keeps record of the path that packet can use as they move across the network. These records are maintained in a database table known as routing table. It can be built statically or dynamically.
  • Router is mainly a Network Layer device.
  • Routers normally connect LANs and WANs together.
Types of Router
  • Wired Router:-Wired routers are box-shaped devices that connect directly to computers through cables or wired connections. One connection port of the wired router used to connect modem for receiving internet data packs, while another set of ports allows a wired router to connect to computers for distributing internet data packets. Examples of the wired router is the Ethernet broadband router.
  • Wireless Router:-Wireless router connects directly to a modem through a cable for receiving internet data packets. Instead of carrying data through cables to computers, wireless routers distribute data packets using one or more antennae. It carries binary code data packets or series of 1s and 0s which converted into radio signals and the antennae broadcast wirelessly.
  • Virtual Router:-Virtual router is acts as a default router for computers sharing a network not like wireless router. The router functions using the virtual Router Redundancy Protocol(VRRP), which becomes active when a primary, Physical router fails or otherwise become disabled.
  • Core Router:-Core router is a wired or wireless router that distributes internet data packets within a network.
  • Edge router:-Edge router is a wired or wireless router which distributes internet data packets between one or more networks
Advantages of Router
  • Routers can normally be coordinated with modems. This  guarantees that wireless access points are given to make little organizations.
  • Routers take utilization of Network address Translation with NAT routers can share the association by utilizing single public IP address and portion of UDP ports.
  • It can reduce network traffic by creating collision domains and also by creating broadcast domains.
  • It provides connection between different network architecture such as ether net & token ring etc.
  • It can choose best path across the internet network using dynamic routing algorithms.
Disadvantages of Router
  • They operate based on routable network protocols.
  • They are protocol dependent devices which must understand the protocol they are forwarding.
  • They are slower as they need to analyze data from layer-1 through layer-3
  • They are expensive compared to other network devices.
  • Dynamic router communications can cause additional network overhead. This results into less bandwidth for user data.
  • A gateway is a passage to connect two networks together that may work upon different networking models.
  • They basically work as the messenger agent that take data from one system, interpret it, and transfer it to another system.
  • Gateways are also called protocol converters.
  • Gateways are generally more complex than switches or routers.
  • A gateway can operate at any of the seven layers of OSI model. It is totally depends upon the functionality.
  • It uses packet switching technique to transmit data across the networks.
Types of Gateway
Gateways are mainly divided into two types on basis of direction of data flow.
  • Unidirectional Gateways:-They allow data to flow in only one direction. Changes made in the source node are replicated in the destination node, but not vice versa. They can be used as archiving tools.
  • Bidirectional Gateways:-They allow data to flow in both directions. They can be used as synchronization tools.
Advantages of Gateways
  • Besides filtering, a gateway can also convert data packets according to the destination needs. If the destination network or architecture has different needs, it can also convert the data format accordingly.
  • A networking gateway has the capabilities to control collision as well as broadcast domain.
  • The main benefit of gateway is the connectivity it provides. A gateway can expand the network by connecting computers with different system together.
  • Gateways are known to posses improved security since they allow user authentication. Forms of security such as user ID and Password can be imposed on gateway so that all the unwanted access will be prevented.
Disadvantages of Gateways
  • Generally gateways on default are installed on the router itself. This makes it more difficult for the network administrator to install or configure them.
  • computers on a network are with different protocols. Therefore, if there is any problem, each of these computers needed to be troubleshooted individually. And this makes the process more complicated.
  • If there are possibilities of failure occurring at the gateway, it can lead to communication loss. Devices on the opposite side will no longer be able to communicate until the problem is resolved.
  • Gateway networks always causes time delay since information must be translated.
  • A repeater operates at the physical layer.
  • A repeater is an electronic device that amplifies the signal it receives.
  • Repeaters receives a signal and retransmits it at a higher level or higher power so that the signal can cover longer distances.
  • It is a 2 port device.
Having a solid understanding of the types of network devices can help you to design and built a network that is secure and serves your organization well.

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