BITS Faculty Publications
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Item Real-time monitoring of network latency in Software Defined Networks(IEEE, 2015) Haribabu, KLatency in a network is an important parameter that can be utilized by Service providers and end users alike. Delay on a network path is often measured using end-to-end probing packets. When multiple end systems measure end-to-end latency, there are overlaps in their paths. Since end systems do not have this knowledge, it results in redundant work and network overhead. In this paper, we propose a method to measure end-to-end path latency in Software Defined Networks (SDN). This method avoids redundant work and measures latency in real-time. Our proposal is an improvement over the looping technique. We simplified the looping technique by using IP TTL as a counter. In order to avoid duplicate work, latency is measured per link and stored in the controller. End systems may register their flow labels with the SDN controller to receive latency information. For each registered flow, controller composes individual link latencies on that path to compute end-to-end latency. We also propose another approach to measure latency using queue lengths at network switches. This technique removes network overhead. In our simulations, improved looping technique is found to be giving better results with reduced computational and network overhead, while the proposed queue length technique shows comparable results.Item Meticulous Measurement of Control Packets in SDN(ACM Digital Library, 2017-04) Haribabu, K; Sinha, YashThe data packet statistics sent by OpenFlow compliant switches cumulatively includes statistics about control traffic which is used for network control and management. This reduces the accuracy of calculation of QoS metrics and thus hampers network monitoring. We present here a novel algorithm to accurately measure the fraction of control packets in SDN within 3% error rate.Item Achieving waypoint enforcement in multi-VLAN hybrid SDN(IEEE, 2018) Haribabu, K; Bhatia, AshutoshThe waypoint enforcement in a network can be seen as the act of diverting the path of packets flowing in the network towards a predefined checkpoint to gain a higher degree of control over the network. Most of the existing solutions which perform waypoint enforcement in hybrid-SDN either disturb the existing VLAN configurations or possess certain limitation in terms of placement of SDN switches in the network. In this paper, we address the problem of achieving waypoint enforcement in a multi-VLAN hybrid software defined network (hybrid-SDN), which does not have these limitations. In particular, the proposed method uses the concept of gratuitous ARP (Address Resolution Protocol) to poison the ARP table of all the hosts in the network to divert the traffic packet towards an SDN switch.Item OpenSnap: Collection of Globally Consistent Statistics in Software Defined Network(IEEE, 2019) Haribabu, K; Bhatia, AshutoshCapturing and monitoring the global state of the network in a software defined network (SDN) is crucial for efficient routing, performance monitoring, Quality of Service (QoS) assurance, etc. The two major existing approaches for statistics collection in SDN are polling-based and event-based. Due to the asynchronous nature of the network, statistics collected through polling have inconsistencies and are not suitable for capturing the consistent global state of the network. On the other hand, event-based monitoring schemes may give sparse information about the network. Globally consistent state detection is well studied for asynchronous systems. However, current SDN standards such as OpenFlow do not support any functionality to collect globally consistent statistics. In this paper, we propose “OpenSnap”, an algorithm to determine the globally consistent state of the system. To support OpenSnap, we extend the OpenFlow protocol by adding a new action. The experimental results show that the statistics collected at the SDN controller using the proposed OpenSnap algorithm are always consistent.Item An Efficient Method to Collect Statistics in SDN Using Curvature Based Sampling(IEEE, 2021) Haribabu, K; Bhatia, AshutoshNetwork management involves measurements and control. Software Defined Networking (SDN) provides a higher level of control on network devices. In SDN, the controller can poll the statistics at different granularity with a constant or dynamic polling rate. There is always a trade-off between the accuracy and polling overhead. This paper proposes a new method for dynamic polling, which provides the best trade-off between the accuracy and polling overhead. We use curvature based sampling as the basis for our method and compute the change in the rate of change to decide the polling frequency. We use real traffic traces for the experiments. The experimental results demonstrate that the proposed method provides better accuracy compared to MoMon [1] and CeMon [2]. The proposed method achieves 23% accuracy over MoMon [1] and roughly three to four times better accuracy than CeMon