Principles Digital Communication System & Computer Networks (Charles River Media Computer Engineering)

2017-07-07 02:10:07

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27.7 BROADBAND ISDN

Narrowband ISDN did not become successful for a long time. With the hope that if users are offered very high data rates to support services such as high definition TV (HDTV), multimedia communication, video conferencing, and so on, broadband ISDN development work was initiated. Broadband ISDN supports 155.52Mbps and 622.08Mbps data rates. However, to support such high data rates, optical fiber has to be used as the transmission medium, and the switching has to be done very fast. The fast packet switching technologies developed as a result of research on broadband ISDN are Frame Relay and ATM, which will be discussed in subsequent chapters.

The fast packet switching technologies—Frame Relay and Asynchronous Transfer Mode (ATM)—have been developed as a result of the research in broadband ISDN.

References

R. Horak. Communications Systems and Networks. Wiley-Dreamtech India Pvt. Ltd., 2002.

http://www.frforum.com The Web site of the Frame Relay Forum. Frame Relay is an outcome of research in broadband ISDN.

http://www.atmforum.com The Web site of the ATM Forum. The ATM technology is an outcome of research in broadband ISDN.

http://www.itu.int The Web site of International Telecommunications Union.

Questions

Explain the ISDN architecture and the various reference points used in the architecture.

Explain basic rate interface (BRI) of ISDN.

What is primary rate interface (PRI) of ISDN?

Explain the ISDN protocol architecture.

Explain the LAPD format.

Exercises

1.	List the various services that can be supported by basic rate interface (BRI).
2.	List the various services that can be supported by primary rate interface (PRI).
3.	"Telemedicine" or medicine from a distance is a service offered for remote rural areas. Study the data rate requirements for providing telemedicine service.
4.	Study the architecture of commercially available terminal adapters.

Answers

1.	Basic rate interface (BRI) provides two 64kbps B channels and one 16kbps D signaling channel. The services supported are voice, slow scan TV at 64kbps, data services such as e-mail, file transfer, and remote login.
2.	Primary rate interface (PRI) provides thirty 64 kbps B channels and one 64kbps signaling channel. High-speed services such as video conferencing at 384kbps and video streaming at 2.048Mbps can be supported.
3.	In Telemedicine, patient information has to be sent to the doctor located at a distant place. Ideally, the video of the patient is sent to the doctor. In addition, x-ray, ECG, EEG, and so forth can be sent. A full-fledged tele- medicine application requires 2Mbps link.
4.	You can obtain the details from http://www.cnet.com and http://www.askey.com.

Projects

Telemedicine is now becoming an important service being provided to rural areas, for which ISDN is extensively used in Europe. Prepare a technical report on telemedicine. Implement a telemedicine system on a LAN.

Prepare a technical report on broadband ISDN.