Browsing by Author "Singh, Deepak"

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Analytical Modelling of Software and Hardware Switches with Internal Buffer in Software-Defined Networks
(2019-06-15)
Singh, Deepak
;
Ng, Bryan
;
Lai, Yuan-Cheng
;
Lin, Ying-Dar
;
Seah, Winston K. G.
Open Flow supports internal buffering of data packets in Software-Defined Networking (SDN) switch whereby a fraction of data packet header is sent to the controller instead of an entire data packet. This internal buffering increases the robustness and the utilization of the link between SDN switches and the controller by absorbing temporary burst of packets which may overwhelm the controller. Existing queuing models for an SDN have focused on the switches that immediately sends packets to the controller for decisioning, with no existing models investigating the impact of the internal buffer in SDN software and hardware switches. In this paper, we propose a unified queueing model to characterise the performance of SDN software and hardware switches with the internal buffer. This unified queueing model is an analytical tool for network engineers to predict a delay and loss during SDN deployments in delay and loss sensitive environments. Our results show that a hardware switch achieves up to 80% lower average packet transfer delay and 99% lower packet loss rate at the cost of requiring up to 50% more queue capacity than a software switch. The proposed models are validated with a discrete event simulation, where the error between 0.6% and 2.8% was observed for both average packet transfer delay and average packet loss rate. Moreover, a hardware switch outperforms a software switch with increasing number of hosts per switch suggesting that a hardware switch has better scalability. We use the insights from the model to develop guidelines that help network engineers decide between a software and hardware switch in their SDN deployments.
Full encapsulation or internal buffering in OpenFlow based hardware switches?
(2020-02-11)
Singh, Deepak
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Ng, Bryan
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Lai, Yuan-Cheng
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Lin, Ying-Dar
;
Seah, Winston K. G.
Software-Defined Networking (SDN) enables programmability in the network through a software dependent control function. OpenFlow is a de-facto protocol for communication between an SDN switch and the controller. OpenFlow specifications generally allow two methods for packet encapsulation of data packets at the switch that require decisions from the controller, (a) full encapsulation, and (b) internal buffering. However, full encapsulation of data packets has been the default choice for packet processing, and internal buffering has not been explored much, especially for hardware switching. In this paper, we model and analyse the effect of internal buffering on the performance of an OpenFlow hardware switch. We compare queueing models for the switch with full encapsulation and internal buffering for hardware switching. The results show that internal buffering significantly reduces the average packet transfer delay by 85% and packet loss probability by 60%. The results further provide guidelines to network operators that internal buffering for hardware switching is useful for controllers with lower processing rates, especially in delay-sensitive applications running over SDN. For loss-sensitive applications running over SDN, the full encapsulation method is more robust handling flows with a high table miss probability. (C) 2019 Elsevier B.V. All rights reserved.
Modelling Software-Defined Networking: Software and hardware switches
(2018-11-15)
Singh, Deepak
;
Ng, Bryan
;
Lai, Yuan-Cheng
;
Lin, Ying-Dar
;
Seah, Winston K. G.
In Software-Defined Networking (SDN), a switch is a forwarding device that moves data packets in a network. A software switch handles forwarding functions in software and thus cannot forward packet at line speed while a hardware switch leverages optimised forwarding hardware to forward packets at line speed. However, there has been very little research in the literature to help network engineers understand the tradeoffs in choosing one over the other. In this paper, we develop a unified queueing model for characterizing the performance of hardware switches and software switches in SDN. The unified queueing model is an analytical tool for engineers to predict delay, packet loss and throughput in their SDN deployments. Existing queueing models of SDN have focused on performance analysis of software switches, while our work presented herein is the first to present a unified analysis of hardware and software switches. Our proposed models exhibit errors below 5% compared to simulation. Between a hardware and software switch, the evaluation shows that a hardware switch achieves an average 80% lower delay and up to 100% lower packet loss probability compared to a software switch. The more a hardware switch involves the controller for decisioning, the lower the gains in terms of packet delays through the switch.
Modelling Software-Defined Networking: Switch Design with Finite Buffer and Priority Queueing
(2017-01-01)
Singh, Deepak
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Ng, Bryan
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Lai, Yuan-Cheng
;
Lin, Ying-Dar
;
Seah, Winston K. G.
Software Defined Networking (SDN) is a new network architecture that separates control plane and data plane. SDN switch models in the literature primarily use queueing theory in two distinct categories: (i) single shared buffer for control plane traffic and data plane traffic, and (ii) buffer with two priorities to isolate control plane and data plane traffic. Several research works have independently studied these two buffer sharing mechanism but do not address the tradeoffs between these two buffer sharing mechanisms. The evaluation shows that shared buffer requires approximately up to 85% higher delays to install the flow table entries in the switch and up to 82% extra buffer capacity compared with the priority queueing buffer.
Modelling Switches with Internal Buffering in Software-Defined Networks
(2018-01-01)
Singh, Deepak
;
Ng, Bryan
;
Lai, Yuan-Cheng
;
Lin, Ying-Dar
;
Seah, Winston K. G.
OpenFlow supports internal buffering of data packets in an SDN switch whereby a fraction of data packet header is sent to the controller instead of an entire data packet. This internal buffering increases the robustness and the utilization of the link between SDN switches and controller by absorbing temporary burst of packets which may overwhelm the controller. Existing queuing models for SDN have focused on the switches that immediately send packets to the controller for decisioning, with no existing models investigating the impact of the internal buffer in an SDN switch and the associated trade-offs of having an internal buffer. In this paper, we propose an analytical model for SDN switch with the internal buffer to investigate the potential benefits, drawbacks and trade-off of internal buffering in SDN switches. It was observed that a switch with internal buffer achieves up to 30% lower average packet transfer delay and 7% lower packet loss rate at the cost of requiring up to 50% more queue capacity than one without the internal buffer. The proposed model is validated with discrete event simulation where the difference between simulation and analytical results was between 0.6% and 2.8% for average packet transfer delay and less than 6% for average packet loss rate. With this investigation, we provide some guidelines to SDN switch designers on the merits, demerits and trade-off of internal buffering in an SDN switch.