Abstract
The explosive growth of VoIP traffic poses a potential challenge to the stability of the Internet that, up to now, has been guaranteed by the TCP congestion control. In this paper, we investigate how Skype behaves in the presence of time-varying available bandwidth in order to discover if some sort of congestion control mechanism is implemented at the application layer to match the network available bandwidth and cope with congestion. We have found that Skype flows are somewhat elastic, i.e. they employ some sort of congestion control when sharing the bandwidth with unresponsive flows, but are inelastic in the presence of classic TCP responsive flows, which provokes extreme unfair use of the available bandwidth in this case. Finally, we have found that when more Skype calls are established on the same link, they are not able to adapt their sending rate to correctly match the available bandwidth, which would confirm the risk of network congestion collapse.
This work was partially supported by the MIUR-PRIN project no. 2005093971 ”FAMOUS Fluid Analytical Models Of aUtonomic Systems”.
This is a preview of subscription content, log in via an institution to check access.
Preview
Unable to display preview. Download preview PDF.
Similar content being viewed by others
References
Baset, S.A., Schulzrinne, H.: An Analysis of the Skype Peer-to-Peer Internet Telephony Protocol. In: Proceedings of IEEE Infocom’06, Barcelona, Spain (Apr. 2006)
Bu, T., Liu, Y., Towsley, D.: On the TCP-Friendliness of VoIP Traffic. In: Proceedings of IEEE INFOCOM’06, Barcelona, Spain (Apr. 2006)
Chen, K., Huang, C., Huang, P., Lei, C.: Quantifying Skype User Satisfaction. In: Proceedings of SIGCOMM ’06, Pisa, Italy (Sep. 2006)
Floyd, S., Fall, K.: Promoting the use of end-to-end congestion control in the Internet. IEEE/ACM Transaction on Networking 7(4), 458–472 (1999)
Floyd, S., Kohler, E.: TCP Friendly Rate Control (TFRC): the Small-Packet (SP) Variant. IETF draft, 20 Nov. (2006)
Handley, M., Floyd, S., Pahdye, J., Widmer, J.: TCP Friendly Rate Control (TFRC): Protocol Specification. RFC 3448, Proposed Standard (January 2003)
Jacobson, V.: Congestion avoidance and control. ACM SIGCOMM Computer Communication Review (1995)
Mascolo, S.: Congestion control in high-speed communication networks using the Smith principle. Automatica (Special Issue on Control methods for communication networks) 35(12), 1921–1935 (1999)
Rejaie, R., Handley, M., Estrin, D.: RAP: An end-to-end rate-based congestion control mechanism for realtime streams in the Internet. In: Proceedings of IEEE INFOCOM ’99, vol. 3, pp. 1337–1345 (1999)
Rhee, I., Ozdemir, V., Yi, Y.: TEAR: TCP Emulation at Receivers - Flow Control for Multimedia Streaming. Dept. of Comp. Sci., NCSU, Tech. rep. (Apr. 2000)
Rizzo, L.: Dummynet: a simple approach to the evaluation of network protocols. ACM SIGCOMM Computer Communication Review (1997)
Global IP Sound. iSAC codec datasheet. [Online] Available: http://www.globalipsound.com/datasheets/iSAC.pdf
Global IP Sound. iLBC codec datasheet. [Online] Available: http://www.globalipsound.com/datasheets/iLBC.pdf
iperf. [Online] Available: http://dast.nlanr.net/Projects/Iperf/
Skype DSP hijacker. [Online] Available: http://195.38.3.142:6502/skype/
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 2007 Springer Berlin Heidelberg
About this paper
Cite this paper
De Cicco, L., Mascolo, S., Palmisano, V. (2007). An Experimental Investigation of the Congestion Control Used by Skype VoIP. In: Boavida, F., Monteiro, E., Mascolo, S., Koucheryavy, Y. (eds) Wired/Wireless Internet Communications. WWIC 2007. Lecture Notes in Computer Science, vol 4517. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-72697-5_13
Download citation
DOI: https://doi.org/10.1007/978-3-540-72697-5_13
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-72694-4
Online ISBN: 978-3-540-72697-5
eBook Packages: Computer ScienceComputer Science (R0)