Home TECHNOLOGY What Is Asynchronous Transfer Mode (ATM)?

What Is Asynchronous Transfer Mode (ATM)?

by Rudresh Ratnaparkhe
asynchronous transfer mode

Do you want to know about the asynchronous transfer mode? What is it, How it works, etc? Then you have come to the right place, here I will explain everything related to it. You will come to understand several points and information that you should know about the ATM. I will share the data that will be very useful and easy for your knowledge. So let us start with what is it.

What Is Asynchronous Transfer Mode?

Asynchronous transfer mode (ATM) is a transfer method implemented by telecommunications networks that require asynchronous time-division multiplexing to encrypt data into small, fixed-sized cells. It is separate from the Ethernet or the Internet that uses variable packet sizes for data or frames. The main protocol which is asynchronous transfer mode still used over the synchronous optical network (SONET). The asynchronous transfer mode history has developed the integrated digital service network (ISDN) and is now core. To support the transmission a system of atm protocols is made.

Services Of Asynchronous Transfer Mode

The ATM services have four different bit rate options. They are given in the following.

  • Available Bit Rate

This has a confirmed minimum capacity, but data can be shifted to higher capacity when network traffic is minimal.

  • Constant Bit Rate

It has a specific bit rate so that data is transmitted to a constant flow. It is identical to the occupied line.

  • Unspecified Bit Rate¬†

This does not specify any output level and is used by applications such as file transfers that can manage delays.

  • Variable Bit Rate (VBR)

It provides the information primarily, but the data is not sent consistently. It is a common alternative for voice and video conferencing.

Benefits Of Asynchronous Transfer Mode

There are different benefits that you will get from the asynchronous transfer mode network.

  • It increases the bandwidth
  • There is a low delay in the transmission
  • It improves network availability
  • The scalability is easy
  • It provides unlimited transmission links

Asynchronous Transfer Mode Cell

The ATM cell is a 53-byte data packet, the standard packet size used by ATM communication technologies. Cells are ATM technologies that are framed for Ethernet networking. The cells are the smallest unit of information for data transmission in the atm switches.

The cell in ATM consists of a 5-byte header and a 48-byte payload as you will see in the following:

asynchronous transfer mode (atm),

Asynchronous Transfer Mode Virtual circuit

ATM is a virtual circuit network that helps in transferring data. A Virtual Circuit is a method of transmitting data over a frame relay computing network. The asynchronous transfer mode notes in such a manner that it looks as if there is a dedicated physical layer for the connection. It is the link between the source and the destination end networks of the data being transferred. There are no leased asynchronous transfer mode lines.

Wireless Asynchronous Transfer Mode

The wireless ATM consists of an ATM core network with wireless network access. Wireless ATM is also called a mobile ATM. The asynchronous transfer mode (atm) network is an example of help in transmitting the ATM cells from cell towers to mobile terminals. Mobile ATMs are developed for providing high-speed information on multimedia communications. It is a technology capable of delivering broadband mobile communications beyond GSM and WLANs. There is a difference in asynchronous transfer mode cost depending upon the multiple traffic in the mobile ATM or wireless ATM.

Asynchronous Transfer Mode Bandwidth

The bandwidth of ATM is very high. This high bandwidth helps in the transmission of the data at high speed. It can transfer both standard high-speed data traffic and real-time low-latency data content easily. The files such as voice files and video files can be sent using it. ATM bandwidth allows transferring of data by using functions of circuit switching and packet switching networks.

Asynchronous Transfer Mode Advantages And Disadvantages

Following are the advantages and disadvantages of ATM:

  • Advantages

  1. The transport of audio, data, and video is optimized with it.
  2. This is a single network for all. 
  3. It manages high traffic in mixed such real-time and non-real-time traffic forms.
  4. It easily integrates with LAN, MAN, and WAN network forms.
  5. This provides smooth connectivity.
  6. It is QoS-oriented and has a high-speed orientation.
  7. It allows the optimized usage of network resources.
  8. It uses a simple network system.
  • Disadvantages

  1. The cell header is only 5 bytes per cell in it.
  2. In it, to complete QoS, complex processes are used.
  3. If there is heavy traffic it can cause cell loss.
  4. The ATM switch is very costly as compared to LAN hardware.
  5. The ATM NIC is more expensive than the Ethernet NIC.
  6. In this process, more time is required for the configuration.
  7. It is a more time-consuming process for disassembly of the connection as it is a network-oriented technology.

Difference Between Asynchronous Transfer Mode Vs Ethernet

You will see the difference between ATM and ethernet as follows

  • ATM has a fixed size that is 53 bytes. While Ethernet has different size range packets.
  • ATM is good for wide area networks. Ethernet is better for LAN or even multiple LAN.
  • In an ATM network, the data is divided and easily transmitted at high speed. In ethernet, the process of routing and switching requires more time.


How Does Asynchronous Transfer Mode Work?

Asynchronous Transmission Mode works as a series of protocols that are used in computer networks. It is primarily used for Wide Area Networks (WAN) that helps in dividing the data and encrypts it into packets of a fixed size. Each packet can be routed separately, along the virtual paths of the network.

Why ATM Is Called Asynchronous?

ATM is called asynchronous because it means that the sources are not restricted for transmitting data during the time slot set. That is the case for the circuit transfer used with the old T1 standby. The ATM transmits data in packets and not in the form of bits or frames. In simple, all data is sent in asynchronous, and the cells are sent synchronously. The ATM is therefore called asynchronous.

Is Asynchronous Transfer Mode A WAN?

Asynchronous transfer mode is a WAN technology. In this, there is a transfer mode for switching and transmitting that easily and efficiently that organizes information through cells. The asynchronous transfer mode wan is asynchronous in the meaning that cell frequency depends on the basic or continuous bit rate.

What Is ATM Protocol In Networking?

ATM protocol in networking is used for telecommunications purposes. It is developed by ANSI and ITU is known as CCITT for the digital transmission of multiple forms of information such as files like audio, data, and video signals. This traffic is sent on a single network without the use of separate network systems.


In this article, I presented an overview of asynchronous transfer mode. You read about the asynchronous transfer mode definition that I explained. Here you understood the communications networks based on the ATM. We described useful information to you which is related to the main aspects of the ATM networks. Some of the queries which are related to the ATM were also answered for your better understanding. You have now come to know about the asynchronous transfer mode in detail.

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