Godkända
Noggrannhet i tidsstämpling för mätningar i höghastighetsnätverk
Rafika Ida Mutia (wx08) och Nayeema Sadeque (wx08)
Start
2009-08-01
Presentation
2010-05-05 10:15
Plats:
E:3139
Avslutat:
2010-05-10
Examensrapport:
(Kontakta handledare)
Sammanfattning
As the demand for high- speed networks grow, it becomes essential to better quantify performance parameters; lowering packet loss, latency, jitter and round-trip time. In addition, improved estimation of available bandwidth and the bottleneck capacity of a network are required in order to effectively manage the network and to adapt to varying rates for different applications. Furthermore, these performance parameters play an important role in networks that employ virtualization which is being explored to a great extent nowadays. One of the things that are needed to study these parameters is an effective time stamping mechanism which can improve measurements. Timestamps on packets are used to study the inter-packet separation from which first as well as second order analysis can be made. First order analysis investigates the delay, jitter and the round-trip time of the packets. The second order analysis estimates the available bandwidth and the bottleneck capacity of the network. Hence, high precision time stamping is desirable to obtain a correct measurement of all these parameters. This thesis will investigate the effect of using a high precision time stamping hardware called DAG cards having a resolution of 15 nanoseconds, and the gain it provides for a bandwidth measurement method known as BART (Bandwidth Available in Real Time). The time-stamping in absence of DAG card is also investigated. This is done by determining where it is best to time-stamp, either in Kernel space or application layer. This is needed to conclude whether DAG card is needed in the absence of jitter. The thesis will also investigate how time-stamping effect networks that employs multiple operating systems on a single computer called virtualization. Time-stamping will be used to examine the variation of throughput with the number of hosts, including the effect of an entire network virtualization in a single host. In the end, the implementation and operation of real time clock in the virtualization software is investigated on top of the clock that being provided on the PC. In conclusion, the purpose of this thesis is to study the effect of time-stamping on performance factors as well as to investigate the performance degradation in virtualized environments.
Handledare: Andreas A Johnsson (Ericsson AB) och Jens A Andersson (EIT)
Examinator: Stefan Höst (EIT)