Conference Papers
Permanent URI for this collectionhttps://idr.nitk.ac.in/handle/123456789/28506
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Item On the effectiveness of CoDel for active queue management(2013) Raghuvanshi, D.M.; Annappa, B.; Tahiliani, M.P.Internet in the present scenario has become a gigantic source of information. There has been a tremendous rise in the variety of Internet applications, with each application demanding a specific performance criteria to be satisfied. Routers presently use Passive Queue Management (PQM) mechanisms and hence, merely have any control over the queue occupancy. Therefore, there has been an increased interest in exploring Active Queue Management (AQM) in Internet routers so as to reduce the queue latency and meet the demands of time sensitive applications. In this paper, we mainly focus on analyzing the effectiveness of a recently proposed AQM mechanism called Controlled Delay (CoDel). We study the effectiveness of CoDel by carrying out simulations in ns-2 and comparing its performance with existing AQM mechanisms in variety of Internet scenarios. Based on the simulation results obtained, we discuss the advantages and shortcomings of CoDel in terms of bottleneck link utilization, mean queue length and packet drop rate. © 2013 IEEE.Item Performance evaluation of CoDel for active queue management in wired-cum-wireless networks(Institute of Electrical and Electronics Engineers Inc., 2014) Jain, T.; Annappa, B.; Tahiliani, M.P.Internet is the major source of information today and its usage is increasing at an alarming rate. A wide variety of data travels over the Internet to cater the needs of end users. This has eventually led to heavy congestion in the network which in turn, worsens the user perceived latency. Internet routers are the main agents that detect congestion prior to end hosts. Traditional router incorporates Passive Queue Management (PQM) strategies which fail to control congestion. Moreover, PQM has several drawbacks which drew the attention of researchers towards the evolution of Active Queue Management (AQM). AQMs are designed to effectively avoid congestion at network routers. AQM apparently became very popular for wired networks, but there are very few researches to find their effectiveness over wireless networks. In this paper we evaluate the effectiveness of a recently proposed AQM mechanism called Controlled Delay (CoDel) in wired-cum-wireless networks. Simulations are carried out by using ns-2 and CoDel's performance is compared with that of Random Early Detection (RED) and Droptail. © 2014 IEEE.Item Implementation and evaluation of Proportional Integral Controller Enhanced (PIE) algorithm in ns-3(Association for Computing Machinery acmhelp@acm.org, 2016) Shravya, K.S.; Murali, S.; Tahiliani, M.P.This paper proposes a new ns-3 model and presents the evaluation results for Proportional Integral controller Enhanced (PIE), a recently designed Active Queue Management (AQM) mechanism to address the problem of bufferbloat. The problem of bufferbloat arises due to the presence of large unmanaged buffers in routers. This leads to high queuing latency and significantly degrades the performance of time-sensitive and interactive traffic. AQM mechanisms that aim to address the problem of bufferbloat try to achieve an optimal trade-off between high link utilization and low mean queue length. PIE is a lightweight AQM mechanism that tries to achieve the same. To our knowledge, ns-3 network simulator does not have a model for simulating PIE. Hence, in this paper, we implement a ns-3 model for PIE, and show that the results obtained from it are in line with those obtained from the ns-2 model of PIE, implemented by its authors. © 2016 ACM.Item On the robustness of AQM mechanisms against non-responsive traffic(Institute of Electrical and Electronics Engineers Inc., 2017) Patil, S.D.; Tahiliani, M.P.Active Queue Management (AQM) mechanisms have come a long way, with an initial goal to avoid congestion to the recent most focus on reducing queue delay. The benefits of using AQM mechanisms at routers are being thoroughly studied nowadays, mainly to avoid the problem of bufferblaat. Although a lot of work has focused on analyzing the behavior of AQM mechanisms, the nature of traffic used while deriving inferences is mainly responsive (TCP), with small numbers of unresponsive flows (UDP) used in the background. The usage of UDP in Internet has increased significantly in the recent past, owing to a great demand for time sensitive multimedia applications. Since UDP flows do not respond to congestion signals, controlling the queue length at routers by using AQM mechanisms becomes a non-trivial task. In this paper, we study the robustness of popular AQM mechanisms in the presence of a large number of unresponsive UDP flows using ns-2. Further, we provide guidelines to effectively tune the AQM knobs and enhance their robustness against non-responsive UDP flows. © 2016 IEEE.Item Implementation and validation of random exponential marking (REM) in ns-3(Institute of Electrical and Electronics Engineers Inc., 2018) Tarte, I.; Joshi, A.R.; Navya, R.S.; Tahiliani, M.P.The problem of bufferbloat has reignited interest in studying Active Queue Management (AQM) algorithms. Significant efforts have been taken by AQM and Packet Scheduling Working Group at IETF to bring more awareness about the performance benefits of deploying AQM algorithms in the Internet. However, experimental analysis of these algorithms is necessary prior to real time deployment. Network simulators like ns-3 are useful tools to perform such preliminary studies. Random Exponential Marking (REM) is one of the popular AQM algorithms. It decouples congestion measure from performance measure, and aims to stabilize the performance measure around the target queue length regardless of the number of users. This paper presents the implementation of a new model for REM in ns-3. The correctness of the proposed model has been validated by comparing the results obtained from it, to those obtained from the ns-2 model developed by authors of REM. © 2017 IEEE.Item Adaptive RED for FreeBSD: Design, Implementation and Challenges(Institute of Electrical and Electronics Engineers Inc., 2019) Pandey, A.; Anand, T.; Shah, M.; Tahiliani, M.P.Bufferbloat problem arises due to buffering of large amounts of data in queues, owing to the large size of these queues. Bufferbloat being a relatively new phenomenon meant that earlier queue management algorithms did not specifically address this problem. Despite this issue, there is merit in analysing and evaluating old queue management algorithms which have helped alleviate the undesirable performance issues that arose due to persistently full buffers. One of the earliest and most significantly studied Active Queue Management (AQM) algorithms is Random Early Drop (RED). RED helps to keep the average size of the queues low and allow occasional bursts of packets through the queue. Once the number of packets queued crosses a minimum threshold, incoming packets are dropped with a random probability. However, the resulting average queue length is quite sensitive to the level of congestion and the RED parameter settings. Adaptive RED (ARED) solves most of the issues faced by RED with minimal changes and leaves its basic idea intact. The ARED algorithm regularly adapts the value of the maximum dropping probability and ensures that the queue length stays within the targeted range. Despite its ability to resolve the inherent problems in RED, ARED went largely unnoticed for several years, until the issue of Bufferbloat arose. Although ARED predates Bufferbloat, its fundamental design makes it an effective solution to handle Bufferbloat. This discovery led to the implementation of ARED in Linux and in network simulators like ns-3. Besides Linux, FreeBSD is one of the most popular open source operating systems. Although RED is supported in FreeBSD, ARED is not. Since ARED is one of the viable solutions to tackle Bufferbloat, this paper discusses the design and implementation of ARED in FreeBSD. We also detail the challenges faced during the implementation, and validate through real testbed experiments that our implementation in FreeBSD exhibits ARED's key characteristics. © 2019 IEEE.