Figure 2-14 Algorithm for call setup request.
Figure 2-15 Connection set up between two end systems through ATM signaling.
Figure 2-15 illustrates how a call setup through the ATM works. First a request is signaled by end-user A to connect to end-user B. This request is routed through intermediate connections establishing a set up path. At that point the call
request is accepted or denied by end-user B. If it is accepted, then the data flows along the same path. Finally the connection is torn down.
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by Abhijit S. Pandya; Ercan Sen CRC Press, CRC Press LLC
ISBN: 0849331390 Pub Date: 110198
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Chapter 3 Services Offered through ATM Networks
One of the key promises of ATM technology besides consolidation of current telecommunication technologies is to provide services, which are not easy or economical to provide with existing
technologies. Some of the key characteristics of these services are: high bandwidth demand, long service duration, bursty traffic patterns, varying quality of service requirements, and asymmetrical bandwidth
usage. In this chapter, we will investigate some of these services such as Internet, Video on Demand, Video Telephony, Distant LearningMedicine and Telecommuting, and explain how ATM can provide
these services economically.
Although some of these services we just mentioned are currently being offered through the existing public telephone network, they are too expensive to be afforded by the general public or there is not enough
bandwidth available to fully utilize these services. Additionally, these fairly new services put a significant burden on the current telephony network that was originally designed for carrying traditional voice traffic.
The voice traffic can be characterized as low bandwidth 64 Kbits, symmetrical, delay sensitive and short service duration, i.e., average 3-minute call duration. However, the new services require bandwidth in the
order of Mbits and the typical service time can be considered in hours. Due to the capacity limitation of the present telephony network, these services are offered either at a premium price or at a lower bandwidth
with substantially lower quality.
I. Internet Service
At the present time, Internet service is expanding rapidly. With the current growth rate it can be assumed that it will surpass the traditional voice service in the near future particularly in the United States.
Especially, with the possibility of offering very cheap voice over Internet service, the Internet poses a significant challenge for telephone network operators.
