Why buffers in switching systems do not essentially improve QoS: An analytical case study for aggregated On-off traffic
| Document type: | Conference Papers |
|---|---|
| Peer reviewed: | Yes |
| Full text: | |
| Author(s): | Gerhard Hasslinger, Markus Fiedler |
| Title: | Why buffers in switching systems do not essentially improve QoS: An analytical case study for aggregated On-off traffic |
| Translated title: | Varför buffertar i switch system inte förbättrar tjänstekvalitén på avsevärd sätt: En analytisk fallstudie för trafik från On-off källor |
| Conference name: | Internet Performance Control of Network Systems |
| Year: | 2002 |
| Pagination: | vol. 4865, pp 47-58 |
| Publisher: | SPIE |
| City: | Boston |
| Organization: | Blekinge Institute of Technology |
| Department: | Department of Telecommunications and Signal Processing (Institutionen för telekommunikation och signalbehandling) Department of Telecommunications and Signal Processing S-372 25 Ronneby +46 455 38 50 00 |
| Authors e-mail: | markus.fiedler@bth.se |
| Language: | English |
| Abstract: | Traffic models with a rate varying according to a Gaussian distribution are commonly used to evaluate statistical multi-plexing in telecommunication systems. The superposition of a sufficient large number of homogeneous Markovian On-Off sources asymptotically approaches an Ornstein-Uhlenbeck process (OUP) which represents a Gaussian process with ex-ponential autocorrelation function. We derive a simple expression for the bandwidth demand under QoS constraints which is close to numerical OUP/D/1 analysis results over the entire parameter region with relevance to applications. In com-parison, results of the fluid flow method for fixed aggregation level are used to verify the OUP/D/1 asymptotics and to estimate its accuracy depending on the number of aggregated flows. Moreover, the OUP/D/1 asymptotics provides a useful check of the accuracy of bounds and approximations proposed in the literature in order to improve the effective bandwidth principle. Based on analytical evaluation, the efficiency of buffers for voice traffic is finally shown to be very limited, i.e. no more than 2% of bandwidth can be saved owing to buffers with regard to real time constraints and a predefined loss probability as QoS demands for voice. |
| Summary in Swedish: | Pappret visar att man tjänar inte mycket på bandbredden genom att buffrar rösttrafik i ett nätverk. |
| Subject: | Telecommunications\Modelling of Bursty Traffics Telecommunications\Fluid Flow Models Telecommunications\General |
| Keywords: | On-off sources, Gaussian traffic, Ornstein-Uhlenbeck process, dimensioning, statistical multiplexing gain |
| Note: | COST Technical Document 279TD(02)013. Presented at the Leidschendam meeting (Feb. 2002). See http://www.lx.it.pt/cost279 |
