What are Repeaters in Computer Network?

Repeaters are network devices operating at physical layer of the OSI model that amplify or regenerate an incoming signal before retransmitting it. They are incorporated in networks to expand its coverage area. They are also known as signal boosters.

Why are Repeaters needed?

When an electrical signal is transmitted via a channel, it gets attenuated depending upon the nature of the channel or the technology. This poses a limitation upon the length of the LAN or coverage area of cellular networks. This problem is alleviated by installing repeaters at certain intervals.

Repeaters amplifies the attenuated signal and then retransmits it. Digital repeaters can even reconstruct signals distorted by transmission loss.So, repeaters are popularly incorporated to connect between two LANs thus forming a large single LAN. This is shown in the following diagram −

Types of Repeaters

According to the types of signals that they regenerate, repeaters can be classified into two categories −

  • Analog Repeaters − They can only amplify the analog signal.
  • Digital Repeaters − They can reconstruct a distorted signal.

According to the types of networks that they connect, repeaters can be categorized into two types −

  • Wired Repeaters − They are used in wired LANs.
  • Wireless Repeaters − They are used in wireless LANs and cellular networks.

According to the domain of LANs they connect, repeaters can be divided into two categories −

  • Local Repeaters − They connect LAN segments separated by small distance.
  • Remote Repeaters − They connect LANs that are far from each other.

Advantages of Repeaters

  • Repeaters are simple to install and can easily extend the length or the coverage area of networks.

  • They are cost effective.

  • Repeaters don’t require any processing overhead. The only time they need to be investigated is in case of degradation of performance.

  • They can connect signals using different types of cables.

Disadvantages of Repeaters

  • Repeaters cannot connect dissimilar networks.

  • They cannot differentiate between actual signal and noise.

  • They cannot reduce network traffic or congestion.

  • Most networks have limitations upon the number of repeaters that can be deployed.