Browsing by Author "Hossain, Md Shohrab"

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Performance modeling and analysis of TCP and UDP flows over software defined networks
(2019-03-15)
Lai, Yuan-Cheng
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Ali, Ahsan
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Hossain, Md Shohrab
;
Lin, Ying-Dar
;
資訊工程學系
Software Defined Networking (SDN) decouples the control plane from the data plane, thereby facilitating network virtualization, dynamic programmability and flexibility in network management. Previous studies on SDN modeling focus only on packet-level arrivals. However, if flow-level arrivals are not also considered, the model cannot properly reflect the true probability of packets being sent to the controller. Accordingly, the present study proposes two analytical models for predicting the performance of TCP and UDP flows over SDN, respectively, given the assumption of both flow-level arrivals and packet-level arrivals. In constructing the models, the switch and controller are considered jointly and four-dimensional states are used to evaluate the steady-state probabilities of the states. Analytical formulae are derived for the average packet delay and packet loss probability of the TCP and UDP flows. Simulation results very well match with the analytical ones, thereby validating our analytical models. The results show that TCP significantly outperforms UDP over SDN architectures. In particular, TCP reduces the packet delay by 12 similar to 50% and the packet loss probability by 25 similar to 100%.
Performance modeling and comparison of NFV integrated with SDN: Under or aside?
(2018-07-01)
Fahmin, Ahmed
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Lai, Yuan-Cheng
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Hossain, Md Shohrab
;
Lin, Ying-Dar
;
資訊工程學系
Software Defined Networking (SDN) focuses on the separation of data and control plane, while network function virtualization (NFV) decouples network functions from underlying hardware. Combining SDN with NFV would have many benefits, but the problem is how to integrate them. There are two possible architectures for such integration: the controller interacts with virtualized network functions (VNFs), or the switch interacts with VNFs. In this paper, the former is referred to as NFV under the controller (NFV_C) while the latter is called NFV aside the controller (NFV_AC). To the best of our knowledge, there is no analytical model for mathematically investigating the performance of such architectures. This paper therefore reports on the analytical modeling of SDN with NFV under or aside the controller. We model and analyze these two SDN + NFV architectures using an M/M/1 queuing model and validate our analysis with various simulations. We show that the analytical results match the simulation results very well. Furthermore, a packet delay reduction of 68.83% can be achieved for NFVAC over NFVC, meaning that NFVAC is a better architecture for integrating SDN with NFV. We also consider feedback from the VNF to the switch. For low loads there is delay increase of 35.42% for high feedback (90%) in comparison with low feedback (10%). In the case of high loads we recorded a delay increase of 66.64%.