Day 7: Hub, Repeater, Bridge, Router, Gateway, ATM, DNS

Hello Dear Students,
     Hope you all are doing good....

So today we are going to cover many basic topics which are as follows-

Let's get started....

  • HUB - Hub is a central controller which controls the traffic on the network. It is a computer networking device that connects the network segments. Various computers/nodes are connected with the Hub. Hub has the following function-
  1. Hub amplifies the signals.
  2. The filtering is not required in the Hub.i.e. it cannot filter the network traffic. 
  3. Hub is basically used as the network concentration points.
  4. Switching is not required.
Passive Hub- Passive hub operates below the physical layer. It is just a connector and is a hardware device which provides the connection between the wires from different branches. In STAR topology, it is just a collision point where signals collides from different nodes/computers. 

Active Hub- Active hub operates at the physical layer. It is a multiport repeater that regenerates the received bits pattern and then send it out to the destination. 

  • SWITCH - Network Switch is a computer networking device that connects network segments. 
previous year paper ugcnetexperts

Answer is Switch.

  • REPEATER - Repeater is a hardware device which operates only at physical layer. A repeater connects segments of a LAN. It is used to increase the no. of nodes in a network. The main function of repeater is to receive signal, and before that signal gets weak, regenerates the original bit pattern and then sends the refreshed signal.

  • BRIDGES - Bridges operates at both physical and the data link layer. As physical layer, it regenerates the signals its receive. As data link layer, it checks the MAC address contained in the frame. However, bridge cannot change the physical MAC address in the frame. Bridge filters the network traffics by only looking at the MAC address. Bridges are not concerned with the protocols and it only tooks the MAC address. Bridges are mainly of 2 types- 
  1. Transparent Bridges
  2. Source Routing Bridges

  • ROUTER - Router operates at physical, data link and network layers. It is a 3-layer device which forwards the data packets based on their logical address. Router connects LAN and WANs in network. It is connected to 2 or more lines in the network. When data comes in these lines, router reads the address information of the packet for its delivery to the destination. 

  • GATEWAYS - Gateways operates at all layers. Commonly used in WANs. Gateway is normally a computer that takes the message, reads it and then interpret it. It provides security also. gateways are used as connecting device of the networks which follows different models. It is generally a software installed in the router. 

  • ATM -  ATM stands for Asynchronous Transfer Mode. It is a WAN technology designed by ATM forum and adopted by ITU-T. ATM aims to design a single technology which can provide voice, video and the data services across WAN. It allows a high-speed interconnection of all world's network by combining it with SONET. Basically designed to optimize the data having packets of size 8Kb larger. The layers of ATM are- 
  1. Application Adaptation Layer(AAL)
  2. ATM layer
  3. Physical layer. 
AAL layer allows the packets to connect with ATM facilities. It allows the transmission of voice, video, data and audio. It divides into small packets called as cells. Each ATM contains 53 octets(5 octets of header). ATM layer provides routing, traffic management, switching and multiplexing services.

  • DNS - DNS stands for Domain Name System. DNS is basically the naming scheme which is used in the Internet. Domain names are hierarchical. It is basically used to name the websites, computers, etc. Large organizations can set up the additional hierarchical name such as
 Domain Name

Assigned to   
 comCommercial Organizations  
 edu Educational institutes          
 gov Government Organizations
 mil Military Group
 netNetwork support centre 
 intInternational Organizations 
 country code      A country

Like our website domain name is - .  

Best of luck students,
    Do share, subscribe and comment if you like our efforts..