In networking, we use many devices to connect with the network or to establish a connection in a network. These devices are known as network devices.
For example, we use Switch to provide internet to the connected computers so that the computers are able to connect with the network.
So, in this article, we will know about some network devices and their properties.
Network Device Hub
In network devices, Hub is a device which receives data frames from senders and send or you can say repeat it to the receivers.
- This device supports Bus Topology. So, at a time it can receive or send the data packets.
- Hub works in Physical Layer.
- Hub can’t store MAC address for which if a sender sends a data packets Hub can’t filter it. So that the data is visible to all connected devices in the network.
- So, Hub is not that much secure for communication.
- Hub sends or receives data by using the IP address. For example, if a sender sends the data to the hub and hub send or repeat it to every device on that network but only the targeted device accepts the data by matching the IP address on that data and other devices will reject the data to receive.
- Hub can receive and send electrical and binary data.
- Hub communicates in Half-Duplex (at a time it can only send or receives the data). For example, if a sender sends data to a receiver then at that time receiver cannot send data. Also, it cannot receive data from other devices. At that time the whole network will stay in neutral.
- Hub is having a single collision domain. It means there is a single path to communicate in the network. For example, Hub has a single path through which data can only send or receive. So, if two devices are sending data at a time then there will be a chance of colliding the data with each other which may lead to data loss.
- Hub is a local area network (LAN) device.
- We can use a hub in a local area like we can use it in our home, in an organization, in an internet store, etc.
Types of Hub
Basically, it is of two types: (I) Active Hub and (II) Passive Hub
Active Hub amplifies the analogue signals and regenerates the digital signals. It consumes electricity to work.
Passive Hub doesn’t need electricity to work or run. Also, it cannot amplify or regenerate data. Whatever data it will receive, without consuming electricity it will send the data to the target device.
Nowadays we are not using Hub because of less security, the chance of data collision, half-duplex networking, etc.
In-network devices, Switch is a multi-port bridge. This device can have 8/6/24/48 ports to communicate. The switch has multiple paths according to the port number. For example, a Switch have eight ports to connect the devices then it should have fifty-six (56) paths to communicate with each other.
The first time, if any device sending data frames to any other device, Switch will record the MAC address of both sender and receiver in his Content Accessible Memory (CAM) table for further communication.
Suppose there are 8 devices which are connected with 8 ports of the Switch. Then Switch will maintain the data like the bellow table.
|PORT No||MAC Address|
After maintaining the table second time it will not broadcast the data frames. According to the port and MAC address, it will send or receive the data frames in an individual path between the receiver and sender.
So that data collision chance is zero here. If one device gets disconnected, Switch will update his CAM table by broadcasting the data again.
- It works in the Data link layer.
- It maintains a CAM table.
- This device has individual collision domains.
Types of Switch
(I) Store and Forward Switch
This type of Switch stores the data first and then forward it to the receiver. After storing the data frames, it will check the data for error or missing of any data frames then it sends the data to the receiver.
Performance of Store and Forward switch is slow. Because it takes time to store and check.
(II) Cut through Switch
This type of switch is not checking the data frame for error. It checks only the MAC address of the data frames and sends it to the receiver.
It is faster than the Store and Forward Switch. But it is not that much reliable.
(III) Fragment free Switch
This type of Switch only checks first 64 bytes. Also, it checks for the error and with the help of MAC address, it sends data frames to the receivers. So, we can say it is the combination of store and forward switch and cut-through switch.
(IV) Adaptive Switch
This type of Switch is the combination of all three (I, II and III) Switches.
Depending on the user requirement Adaptive Switch can work like (I) Store and Forward Switch, (II) Cut through Switch and (III) Fragment free Switch.
In-network devices, it is an internetworking device. We use it to establish communication between two different networks.
Suppose an institute of India has a network of several devices. So, that they can communicate with each other. But, if the institute of India wants to communicate with the Institute of America then they have to use Router for establishing communication between them.
This device maintains a routing table to record the port number and IP address of the devices.
By using IP address router sends data in the form of packets to the receivers.
- It works in Network Layer.
- In every port, it has its own broadcast domain.
- It maintains a routing table.
- It is a Wide Area Network (WAN) device.
In-network devices, it is a device which amplifies or repeat the data or signals. This device is quite similar to Hub
- It works in the physical layer.
- It is also a LAN device. Works in the local area.
- Also, it can’t store the MAC (media access control) address.
- It can send or receive both analogue and digital signals.
In-network devices, Gateway is an entry or exit point of a network.
For example: If a sender sends data to another network then the data need to enter to that network through the Gateway.
- It works in Application Layer.
- It works with Router.
- This device decides, where the data have to send.
In-network devices, it is a device which inspects the traffic on a network and decide to accept or reject. This device is a little bit intelligent then a hub. To overcome partially from the problem of the hub which is broadcasting, we use Bridge.
Suppose the connected bridge has two port-I and II to connect. In port-I, there are four devices A, B, C and D and in port-II, there are three devices E, F and G.
Suppose device-A wants to send a data frame to device-F. So, first, device-A will send the data frame to the bridge then the bridge will broadcast the data frame to all over the network. Like hub, the target device-F only accept the data frame with the help of IP address and others will reject it. At that time Bridge will maintain a Bridge table in which it will record the MAC address of device-F and the port no of the Bridge where the device-F is connected.
|Port Number||MAC Address|
Next time when device-A will send data to device-F, Bridge will not broadcast the data to all over the network, it only broadcast the data to the devices of port-2 because the device-F is connected in port-2
In this way, Bridge will collect or record all the device port number and MAC address and communicate.
So, Hub is a device which broadcast to every device but Bridge broadcast only in one port where the receiver device is connected.
- It works in the Data link layer.
- We use it to connect two or more LAN network.
- It filters the data frames on the basis of ports of the Bridge.
- This device reduces the traffic of a LAN network by dividing it into the number of ports.
- In Bridge, there are two collision domains.
Also know about network topology.
Basically Hub, Router, Switch, Repeater, Bridge and Gateway are the different types of networking devices. We can communicate with other devices of a network by the help of these network devices.
The device which connects one network with other networks is known as an internetworking device. The router is an internetworking device.
Hub is a device which receives data frames from senders and send or you can say repeat it to the receivers. This device supports Bus Topology. So, at a time it can receive or send the data packets. Hub works in Physical Layer.
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