Predavanje: Online games: is the Internet prepared for them?

Abstract

The Internet was designed as a best-effort network, which does not warrant a maximum delay. This was enough for traditional services, as web browsing, e-mail or file transfer. However, new real-time services, as online games, are raising this problem: is the Internet adequate for them? Online games are a real-time service in which delay is really critical. Research has shown that the maximum delay tolerated by gamers is about 150 to 200 milliseconds. In addition, gamers are difficult to satisfy: if a game does not work properly, they leave the server and never return. Many efforts have been done in order to introduce new mechanisms allowing Quality of Service (QoS), but we are still far from the perfect solution.

Other interesting question is related to packet size, which usually ranges from 40 to 1,500 bytes. Since every packet has to include the IP and the TCP or UDP headers, we have a simple rule: the bigger the packet, the better the efficiency. Traditional services tend to maximize packet size: since delay is not critical, they can wait until they have almost 1,500 bytes to send. But the problem with real-time services is that the information has to arrive fast, and also with a fixed cadence. Therefore, tiny information chunks are sent using a high frequency, and this implies generating very small packets.

Multiplexing a number of payloads into a single packet can be seen as a way to improve network efficiency. If a number of flows share the same path from an origin to a common destination, then a multiplexer can build a bigger packet in which many payloads share a common header. The headers of the original packets can also be compressed in order to increase bandwidth savings.

As a consequence, a multiplexing standard is being currently deployed for online games. Research has shown that significant bandwidth savings can be obtained without harming the subjective quality.

Speaker Biography

JOSE SALDANA (jsaldana@unizar.es) was born in San Sebastian, Spain, in 1974. He received his B.S. and M.S. in Telecommunications Engineering from University of Zaragoza, in 1998 and 2008, respectively. He received his PhD in Information Technologies in 2011. He is currently a research fellow in the GTC working Group of the Department of Engineering and Communications of the same University. His research interests focus on Quality of Service in Real-time Multimedia Services, as VoIP and networked online games. He also studies the problem of optimizing the traffic by multiplexing and header compression techniques. He is a member of IEEE Communications Society, and is the author of about 30 research articles in scientific Journals and Conferences. He has also presented standard proposals to IETF, and has participated in 10 research projects. He is also member of the Technical Program Committee of some conferences and workshops, as IEEE CCNC-DENVECT 2012 and NOSSDAV 2012.