What is Asynchronous Transfer Mode? | Web Technologies Part 4

Circuit switch network

What is Asynchronous Transfer Mode?

Hello, I’m Sourav Khanna and welcome to our today’s session on web technologies Part Four. Today I’m going to be discussing the difference between circuit-switched and packet switch networks. Then I’m going to move on to a discussion comparing frame-relay versus Asynchronous Transfer Mode. And then we’re going to conclude with multi-protocol Label Switching. There’s a whole lot of ground to cover, not a whole lot of time. Let’s go ahead and begin the session. Let’s begin this session by talking about circuit-switched and packet-switched networks.

Circuit switch networks

Circuit switch networks have a dedicated circuit between two endpoints that are used for communication. While setting up the circuit can only be used for communication between those ends. Circuit switch networks are most common in networks with leased line communication channels. They’re best used when there needs to be a fair amount of continuous data traffic between the two endpoints. In what circuit switch networks, there is only one path for the data to take.

what is asynchronous transfer mode

On the other hand, in packet switch networks data is broken up into smaller chunks and moved through the network only to be reassembled at the other end. The data is routed using the destination address and the data may take different paths through the network that it’s travelling through. As a general rule, packet switch networks are less expensive to maintain.


Because the user doesn’t have to maintain a dedicated circuit 24 seven, they’re only paying for what they’re using. Now let’s talk about the differences between frame relay and Asynchronous Transfer Mode. Frame Relay is a wind technology in which variable-length packets are switched across the network. Frame Relay is less expensive than leased lines. But frame relay can be made to look like a leased line through virtual circuits or VCs.

Frame Relay Network

A-frame relay network will track a VC using a Data Link connection identifier to identify the end of the VC. There are two terms associated with frame relay that you should be aware of. The first is the access rate. That is the maximum speed of the Frame Relay interface. The other term is the committed information rate, the CIR, that’s the guaranteed bandwidth that a customer receives. So that’s the minimum speed of that frame relay network, the access rate may be higher, but the customer is always guaranteed the committed information rate.

Asynchronous Transfer Mode

Now let’s talk about Asynchronous Transfer Mode, also known as ATM. ATM is a wind technology in which fixed-length cells are switched across the network. These cells are always 53 bytes long. ATM can handle real-time voice and video because it’s very fast, but it has poor bandwidth utilization. The small cell size reduces the efficiency of the technology. But ATM is very fast even if it is inefficient. Common speeds on an ATM network are 51 points 84 megabits per second and 155.52 megabits per second. Let’s conclude with multiprotocol Label Switching. The acronym for multi-protocol Label Switching is MPLS. MPLS is a topology that’s growing in popularity.

Why? Because it’s scalable. Also, it is protocol independent MPLS that can be used to replace both frame-relay switching and ATM switching. It can be used to packet switch both frame relay and ATM network traffic. This allows MPLS to be used with both frame relay and ATM technologies. MPLS is often used to improve the quality of service and flow of network traffic. It uses a label edge router to add MPLS labels to incoming packets if they don’t have them. The label edge router then passes those packets onto a Label Switching router or LSR router. The LSR forwards those packets based on their MPLS labels to their final destination.

Now that concludes this session on when technologies Part Four, I talked about the differences between a circuit-switched and packet switch network. Then we moved on to frame relay versus Asynchronous Transfer Mode. And we concluded with a brief discussion on multi-protocol Label Switching.

In the next article, we will talk about Networking Cabling. For our previous articles on computer networking visit here.

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