Difference between Frame Relay and ATM

The OSI model's data link layer defines the methods for encapsulating data for transmission between two endpoints and the mechanisms for transferring frames. Frame relay and Asynchronous Transfer Mode (ATM) are both data link layer technologies with connection-oriented protocols. The main distinction between frame relay and ATM is based on transmission speed, efficiency, packet delivery accuracy, etc. The frame relay can be 1.544 Mbps or 44.736 Mbps, whereas the ATM offers 51 or 155 Mbps.

In this article, you will learn about the difference between Frame Relay and ATM. But before discussing the differences, you must know about Frame Relay and ATM with their advantages and disadvantages.

What is Frame Relay?

Frame relay is a packet mode communication service that is designed to manage enhanced WANs. X.25 was the previous technology utilized in place of frame relay, although it has some drawbacks like poor data rate, an unnecessary increase in flow rate, and error control.

Its service employs either a permanent or switching virtual circuit to create the link and permit the transfer of bits from source to destination at a reasonable speed and price. Before the introduction of frame relay and X.25, slow telephone connections were utilized for their specific purpose. The key limitations of previous technologies were network delays, protocol overheads, and equipment costs.

Frame relay offers data speeds ranging from 64 Kbps to 45 Mbps. It has a variable packet size and does not include error and flow management. The responsibility of the frame relay is limited.

Advantages and Disadvantages of Frame Relay

There are various advantages and disadvantages of Frame Relay. Some main advantages and disadvantages of Frame Relay are as follows:

Advantages

1. It supports a frame size of 9000 bytes, which is sufficient for all LAN frame kinds.
2. It provides a secure connection because the PVCs between the locations are tough to break.
3. At the user-network interface, it performs fewer functions.
4. It has faster speeds. It is due to the lack of error detection, which reduces overhead. It has a higher throughput than X.25.
5. It supports bursty data with no defined data rate.
6. The bandwidth can be dynamically assigned based on demand.

Disadvantages

1. It may only run at 44.376 Mbps, making it unsuitable for protocols that need higher data rates.
2. It does not support flow control or error control.
3. It supports variable-length frames, which may result in various latencies for different users.
4. It is more expensive than internet access.
5. There is data overhead and processing overhead with each packet.

What is ATM?

ATM is an abbreviation for "Asynchronous Transfer Mode". It is a switching mechanism that was developed by combining the elements of telecommunication and computer networks. ATMs employ cells to transfer information in a variety of service forms like as voice, data, and video. ATM data transfer has fixed-size 53-byte cells, and an ATM cell has a 5-byte header and 48 bytes of ATM payload. Its smaller size and fixed-length cells are ideal for delivering image, voice, and video data because the delay is minimized. It is a connection-oriented protocol. Therefore, a virtual circuit must be created between the transmitting and receiving sites. When the data transfer begins, it makes a fixed route between two sites.

Its other significant feature is an asynchronous operation in time division multiplexing. As a result, cells are only transmitted when data is available to be sent, as opposed to conventional time division multiplexing, which transfers synchronization bytes when data is unavailable to be sent. ATM is intended to be simple to implement in hardware. Therefore, processing and switching have become faster. ATM networks may support bit rates of up to 10 Gbps. ATM is a core protocol that is utilized over the ISDN's SONET/SDH backbone.

ATM offers a high level of service in networks that support many types of data like voice, images, video, etc. Each data type may transit across a single network connection using ATM.

Advantages and Disadvantages of ATM

There are various advantages and disadvantages of the ATM. Some main advantages and disadvantages of the ATM are as follows:

Advantages

1. It offers large bandwidth.
2. It is easy and simple to integrate with MAN, LAN, and WAN networks.
3. It utilizes a simplified network infrastructure.
4. It is designed to transfer voice, video, and image data over a single network. It is utilized for mixed traffic, real-time and non-real-time traffic.
5. It makes effective use of network resources by utilizing the bandwidth-on-demand concept.
6. It is less vulnerable to noise deterioration.

Disadvantages

1. ATM switches are more expensive than LAN hardware. Additionally, ATM NIC is more expensive than Ethernet NIC.
2. The cell header generates greater overhead.
3. Congestion can cause cell losses.
4. As ATM is a connection-oriented technology, the time needed to set up and pull down the connection is greater than the time needed to use it.
5. Complex mechanisms are utilized to achieve QoS.

Key Differences between Frame Relay and ATM

There are various key differences between Frame Relay and ATM. Some main differences between Frame Relay and ATM are as follows:

1. Frame relay utilizes a variable packet size. As a result, it has a low overhead within the packet, making it an efficient method of transferring data. In contrast, the ATM has a fixed packet size and may be advantageous for managing video and image data at high rates. It leaves a huge overhead within the packet, mainly in short transactions.
2. Frame relay doesn't offer flow and error control. Upper layers must support these functions. In contrast, ATM data is segmented and packed into the ATM cells. Each ATM call has a 5-byte header and 48 bytes of payload data. The header portion of the ATM cell has an 8-bit error control field that is utilized for error control. It offers user-level flow control for a network interface.
3. Frame relay doesn't offer quantifiable support quality. In contrast, the ATM enables quantifiable support quality.
4. The cost of frame relay is low than ATM. In contrast, the ATM is more expensive than the frame relay.
5. Frame relay works at layer 1 and layer 2 of the OSI stack. In contrast, ATM works at the physical layer and data link layer.
6. The frame relay is less reliable. In contrast, the ATM provides good reliability.
7. The frame relay's packet transfer speed is too slow. In contrast, ATM's packet transmission speed is too fast than the frame relay.
8. The frame relay is not compatible with LAN or CAN. In contrast, the ATM works with LAN and CAN.
9. The packet delay is high with the frame relay. In contrast, the packet delay is less in the ATM.
10. The throughput of the frame relay is moderate. In contrast, the throughput of the ATM is high than the frame relay.

Head-to-head comparison between Frame Relay and ATM

Here, you will learn the head-to-head comparisons between Frame Relay and ATM. The main differences between Frame Relay and ATM are as follows:

Conclusion

The frame relay is managed and controlled by software, whereas ATM is based on hardware, making it more expensive and faster. ATM may achieve faster processing and switching speeds by enabling flow and error control.