ATM is a high-speed networking standard designed to support voice, image, video, and data communications through fixed-size cells. It provides high bandwidth, high data transfer rates, quality of service, and efficient bandwidth allocation. ATM is used for both constant rate traffic like audio and video as well as variable rate traffic like data. It can be implemented through a company's own ATM network or through fixed connections from network operators. While ATM requires new hardware and software and has some complexity, it allows for a single network connection that can easily mix different media types.

1. ATM
Shweta raichura

2. What is ATM?????
•ATM is a high-speed networking standard
designed to support voice,image,video and
data communications.

3. Why ATM is used?????
• ATM provide larger bandwidth, high speed data transfer rate,
quality of service and grade of service.
• ATM transmits all information in small, fixed-size packets called
cells.
• In ATM cell switching is used because it is highly flexible and can
handle both constant rate traffic (audio, video) and variable rate
traffic (data) easily.

4. How ATM is used???
• ATM is a transmission technique:
• A company can implement its own ATM network.
Network operators provide fixed ATM connections
for subscribers on a permanent contract basis

6. Advantages of ATM….
• High-speed communication.
• Provides the best multiple service support
• A single network connection that can easly mix
voice, video, and data.
• efficient allocation of network bandwidth.

7. Disadvantages of ATM…
• New customer premises hardware and software are
required.
• ATM used fix size cell.
• ATM is a complex standard,complexity makes the
implementation expensive - lots of parts required.

8. Protocol Architecture

9. Physical Layer:
•The lowest layer in the ATM protocol.
•It describes the physical transmission media. We can use
coaxial cable, and fiber-optic cable.
ATM Layer:
•It performs all functions relating to the routing and
multiplexing.
•It generates a header to the segment streams generated by the
AAL. Similarly, on receipt of a cell streams, it removes the
header from the cell and pass the cell contents to the AAL
protocol.
•To perform all these functions, the ATM layer maintains a
table which contains a list of VCIs

10. ATM Adaptation Layer:
•Top layer in the ATM protocol Model. It converts the submitted
information into streams of fixedsize segments and transports these in
the payload field of multiple ATM cells.
•This layer is used for in order to support information transfer
protocols
•Examples of services that need adaptations are Gigabit Ethernet, IP,
Frame Relay.

11. ATM Services
1- Constant Bit Rate (CBR):
• CBR is used by a connections that requires a static amount of bandwidth that is continuously available
during the connection time.
• It appropriates for such applications as telephone traffic, video conferencing, interactive Audio,
TV
2- Rate-Non-Real Time Variable Bit (nrt-VBR)
• Allows users to send traffic at a rate that varies with time depending on the availability of user
information.
• Application: email.

12. 3- Available Bit Rate (ABR)
•Available Bit Rate (ABR) is a service used in ATM networks when source and destination don't need to
be synchronized
•Depending on the state of congestion in the network, the source is required to control its rate.
Allows users to declare a minimum cell rate guaranteed to the connection by the network.
Aimed at data traffic such as file transfer and e-mail.
4- Unspecified Bit Rate (UBR)
Intended for non-real time application which do not require tightly constrained delay and delay
variation.
Widely used today for TCP/IP

13. 5- Rate-Real Time Variable Bit Rate (rt-VBR):
Intended for those application which requires tightly constrained delay and delay
variation.
Application: voice with speech activity detection (SAD) and interactive compressed
video.

14. Conclusion
• ATM is a flexible and powerful technology which integrates the cell-
switching and multiplexing functions, and enables transmissions over a
variety of carrier system.
• ATM technology is a powerful common platform for LAN and WAN to
increase productivity, to reduce costs and to implement new applications and
service.

15. Thank you….