Performance analysis of TCP in KVM virtualized environment

Abstract: The requirement of high quality services is increasing day by day. So, in order to meet up with this requirement new technologies are being developed one of them being virtualization. The main agenda of introducing virtualization is that though virtualization needs more powerful devices to run the hypervisor, the technique also helps to increase consolidation which makes efficient use of resources like increase in the CPU utilization. The virtualization technique helps us to run more VM’s (Virtual Machine) on the same platform i.e. on the same hypervisor. In virtualization as number of VM’s share the CPU will there be any effect on the performance of TCP with the performance influencing factors of virtualization. While TCP being the most widely used protocol and most reliable protocol can performance of TCP vary if different TCP congestion control mechanism are used in the virtualized environment are the main aims of this research.   In this study, we investigate the performance influencing factor of TCP in the virtualized environment and whether those influencing factors have any role to play with the performance of the TCP. Also which TCP congestion control mechanism is best suitable in order to download files when virtualization is used will be investigated by setting up a client-server test bed. The different TCP congestion control mechanism which have been used are CUBIC, BIC, Highspeed, Vegas, Veno, Yeah, Westwood, LP, Scalable, Reno, Hybla. Total download time has been compared in order to know which congestion control algorithm performs better in the virtualized environment.   The method that has been used to carry out the research is by experimentation. That is by changing the RAM sizes and CPU cores which are the performance influencing factors in virtualization and then analyzing the total download time while downloading a file by changing the TCP congestion control mechanisms by running a single guest VM. Apart from changing only congestion control mechanisms the other network parameters which effect the performance of the TCP such as Delay have been injected while downloading the file, to match up with the real time scenarios.   Results collected include average download time of a file by changing the different memory sizes and different CPU cores. Average Download time for different TCP congestion controls mechanisms with inclusion of the parameter that effects the total download time such as Delay.   From the results we got we can see that there is a slight influence on the performance of TCP by the performance influencing factors memory sizes and CPU cores allotted to the VM in the KVM virtualized environment and of all the TCP congestion control algorithms having TCP – BIC and TCP- YEAH performs the best in the KVM virtualized environment. The performance of TCP – LP is the least in the KVM virtualized environment.