Conference Papers
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506
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Item Modified RED algorithm to improve the performance of web traffic(2013) Dadhania, M.K.; Kumar, K.V.Reducing the delay of web traffic has been an important issue in Internet works. However, it is difficult to reduce delay while improving throughput. This is because, in order to reduce delay queue size should be less but to improve throughput queue size should be more. In our modification, web traffic and ECN marked packets are dropped only when high congestion occurs at router. We propose a solution to improve response time as well as the number of packets transmitted of web traffic without affecting throughput of bottleneck link. We applied this solution to RED algorithm and tested the performance and efficiency of modified RED algorithm as compared to the original RED algorithm. © 2013 IEEE.Item Extended ECN mechanism to mitigate ECN-based attacks(Institute of Electrical and Electronics Engineers Inc., 2014) Bommisetti, S.; Annappa, B.; Tahiliani, M.P.Today, usage of internet is growing exponentially. Congestion detection and avoidance algorithms are the major issues in TCP/IP. Earlier, packet drops are only source of congestion indication, but it leads to loss of throughput. Active Queue Management (AQM) can detect congestion before the queue overflows and informs the end hosts to respond congestion. It allows gateways to drop packets when average queue is greater than maximum threshold and marks the packets otherwise. Explicit Congestion Notification (ECN) mechanism marks the packets when the average queue size is between predefined thresholds and improves the throughput of a network. But it depends on the end hosts to respond to congestion. So there is a possibility of misbehavior by sender to increase its congestion window, even if the receiver correctly signals about congestion. So misbehaving ECN sender flow obtains more throughput than the normal ECN-enabled flows. We present an Extended ECN mechanism that enables a router to mark packets and the receiver to signal congestion to the sender without trusting the sender whether it has responded congestion or not. Our improved mechanism is robust in detection and prevention of this misbehaving sender in network and compatible with ECN and TCP/IP mechanisms. © 2014 IEEE.Item Situation-Based Congestion Control Strategies for Wired and Wireless Networks(Institute of Electrical and Electronics Engineers Inc., 2018) Kharat, P.; Kulkarni, M.Performance of transport layer is measured mostly in terms of packet delivery ratio, transmission delay, and throughput. Congestion control (CC) strategies are responsible for transport layer performance. There are different congestion control algorithms are designed and developed by researchers to handle shared, highly distributed and heterogeneous environment. In this paper, we are analyzing most of the popular congestion control algorithms based on link state, type of traffic, mode of transmission and bandwidth delay product (BDP). In the proposed algorithmic solutions, networking researchers not only looking for congestion but also taking care of effective use of network resources in different types of environments such as wired, wireless, high-speed, long-delay, etc. To avoid severe congestion based on feedback mechanism few packets are dropped randomly by using active queue management (AQM) techniques. Using explicit congestion notification (ECN) mechanism unnecessary packet dropping is avoided. Data center network (DCN) uses a different approach to handle congestion. © 2018 IEEE.Item A principled look at the utility of feedback in congestion control(Association for Computing Machinery, 2019) Tahiliani, M.P.; Misra, V.; Ramakrishnan, K.K.Networked applications are ubiquitous and their performance requirements are becoming increasingly stringent. Network congestion can seriously impact performance contributing to increased latency, packet loss and poor throughput. To address these problems, the networking community has come up with a large number of congestion control algorithms. Congestion control schemes developed over the past few decades can be classified into two broad classes: one based on an end-system's perception of network congestion and the other based on the network providing feedback to flows that pass through it. In this paper, we make the observation that the pure end-system based congestion control schemes are faced with the significant challenge of receiving ambiguous signals that make it difficult to infer where the congestion is occurring and if this flow is even the cause of that congestion. This ambiguity makes it difficult for pure end-system based control schemes to achieve fairness across different flows. Modern routers and switches in the meantime, have grown in computing capability and can generate fine grained feedback at line speeds for flows traversing them. We show that even relatively simple feedback generated in-network at the point of congestion eliminates the ambiguities faced by pure end-system based congestion control mechanisms, thus ensuring the network functions at the right fair and efficient operating point. We provide the theoretical underpinnings establishing the need for in-network feedback to enable the network to operate at a unique fixed point at the intersection of the desired fair and efficient operation regimes, and demonstrate through emulation experiments that our use of the well-established and studied PI-control for Active Queue Management and Explicit Congestion Notification meets the goals of low latency, high throughput and fine granularity control of the queue while achieving fairness. © 2019 Copyright held by the owner/author(s). Publication rights licensed to ACM.Item BBRvl vs BBRv2: Examining Performance Differences through Experimental Evaluation(IEEE Computer Society help@computer.org, 2020) Nandagiri, A.; Tahiliani, M.P.; Misra, V.; Ramakrishnan, K.K.BBR, a congestion control algorithm proposed by Google, regulates the source sending rate by deriving an estimate of the bottleneck's available bandwidth and RTTof the path. The initial version of BBR, called BBRvl, was found to be unfair, getting higher than the fair share of bandwidth when co-existing on bottleneck links with other congestion control algorithms. It also does not perform as well with networks having routers with shallow buffers. To overcome these concerns, a newer version, called BBRv2, has been proposed. Our goal in this paper is to understand the differences between the two versions and examine the primary reasons behind the improvement in performance of BBRv2. We present an experimental evaluation of BBRvl and BBRv2, evaluating their fairness across connections using the same protocol (intra-protocol fairness) and using different protocols (inter-protocol fairness) as well as delay and link utilization. From experiments with shallow and deep buffers, BBRv2 is most effective when it uses Explicit Congestion Notification (ECN), but fairness issues continue to exist in BBRv2 when ECN is disabled. A concern for BBRv2 is that it is somewhat complex to deploy in Wide Area Networks (WAN) because of the dependency with the DCTCP-style reduction of the congestion window, which is primarily usable in low-feedback delay Data Center Networks. © 2020 IEEE.