A study of delay factors in CSCW applications and their importance
Multimedia CSCW applications are rapidly becoming mainstream business tools. If users are to be able to perform useful tasks with these tools the acceptability of the subjective quality of the service must be adequate. This acceptability is affected by many factors, including the user interface, the task undertaken, the audio and video coding, the connection speed and the network performance. The end-to-end delay has been identified as a significant parameter affecting the user's satisfaction with the service. Earlier work identified the delay bounds for which the quality of the CSCW service was acceptable to users performing real tasks. These limits formed the basis for an investigation to identify which system components contribute most to this delay. The components contributing to the delay of audio and video have been measured and the major sources identified.
KeywordsVideo Frame Video Stream User Acceptance Communication Path Internet Engineer Task
Unable to display preview. Download preview PDF.
- 1.Braden, R., Clark, D., Shenker, S.: Integrated Services in the Internet Architecture: an Overview, Internet Engineering Task Force, Request For Comment 1633 (1994)Google Scholar
- 2.Fluckiger, Understanding networked multimedia, London, Prentice Hall.Google Scholar
- 3.Ranta-aho, M et al: Task-dependent User Requirements for Quality of Service of Videoconferencing-CSCW services, Proc. of Human Factors in Telecommunication'97 (1997) 251–254Google Scholar
- 4.Laubach M.: Classical IP and ARP over ATM, Internet Engineering Task Force, Request For Comment 1577, (1994)Google Scholar
- 5.Mills, D. L.: Network Time Protocol (Version 3) Specification, Implementation, Internet Engineering Task Force, Request For Comment 1305, (1992)Google Scholar
- 6.Moldeklev, K.: Performance Issues of Internet End Systems, Telektronikk, Vol. 93. No. 2 (1997) 33–45Google Scholar
- 7.Mathis, M., et al: TCP Selective Acknowledgement Options, Internet Engineering task Force, Request For Comment 2018 (1996)Google Scholar
- 8.Jacobson, V., et al: TCP Extensions for High Performance, Internet Engineering Task Force, Request For Comments 1323 (1992)Google Scholar
- 9.Romanow, A., Floyd, S.: Dynamics of TCP Traffic over ATM Networks, IEEE JSAC Vol. 13. No. 4 (1995) 633–641Google Scholar
- 10.Stellings, W. R.: TCP/IP illustrated Volume 1 — the Protocols, Reading, Mass., Addison-Wesley (1994)Google Scholar