Optimal size of data packets in computer networks

First-in-First-out (FIFO) is one of the simplest queuing policies used to provide best effort services in packet-switched network. However, the performance of FIFO is really crucial when it related to stability i.e. question of whether there is a bound on the total size of packets in the network at all times. In this study, our main objective is to find the optimum packet size of voice packet when using FIFO scheduling policy. Our approach is based on adversarial generation of packets so that positive results are more robust in that they do not depend on particular probabilistic assumptions about the input sequences. In this paper, we proposed the FIFO scheduling technique that uses adversarial queuing model to find the optimum packet size of voice packet in FIFO network. Although the simulation results show that the average packet loss is increase when the arrival packet is increased, the average packet delay is improved as compared to FIFO M/M/1 technique, studied by (Phalgun, 2003). This algorithm can be utilized for transmitting voice packet over IP.

Computer-mediated communication in various forms is already being used in all phases of disaster management--preparation, response, recovery, and long-term mitigation. However, to date wide area computer networks--particularly the Internet (the supernetwork of networks)--have been used only to a limited extent in disaster management and prevention. Some of these applications are described in this paper. Nevertheless, the high speed and ease of information transfer by computer network and the vast resources becoming available on the Internet make it inevitable that the use of computer networks to temper disasters will increase enormously in the next decade. The Internet will provide a key means through which networks initially dedicated to solely medical purposes and the individuals who use them will become involved not only in disaster response and mitigation worldwide, but in the global community and consciousness that is the Internet.

The proposed study is devoted to the development of an algorithm for detecting network attacks. The considered approach to detection of attacks is based on monitoring and the description of states of the behavior of data packets in networks of the Internet of things. The developed network attack detection subsystem demonstrates high efficiency in detecting unknown deviations in the process of data packet transmission. The proposed attack detection technology can be used to protect data packets in public IoT networks, where there is a high probability of new cyberattacks. The greatest efficiency of the developed algorithm is achieved in IoT systems, where the use of classes of certain network attacks is limited to online services and does not change significantly over time. This algorithm allows the use of programmed models of the normal behavior of network packets to detect possible cyberattacks.

In this paper, we investigate the effect of packet size selection on the performance of media access control (MAC) protocols for underwater wireless sensor networks, namely, carrier sense multiple access (CSMA) and the distance-aware collision avoidance protocol (DACAP). Our comparative analysis, conducted via ns-2 simulations, considers scenarios with varying, nonzero bit error rate (BER) and interference. We investigate metrics such as throughput efficiency (the ratio between the delivered bit rate and the offered bit rate), end-to-end packet latency, measured “per meter” to allow for different sizes of deployment areas, and the energy consumed to correctly deliver an information bit to the network collection point. Our results show the dependence of these metrics on the packet size, indicating the existence of an optimum. The optimum packet size is found to depend on the protocol characteristics, the bit rate, and the BER. For each protocol and scenario considered, we determine the packet size that optimizes throughput performance, and we show its effect on the normalized packet latency and on energy consumption.

Chapter 1 - Introduction

In pursuit of better energy efficiency and enhanced network lifetime in wireless sensor networks (WSNs), two crucial factors are data packet size and transmission power level. On one hand, smaller packet size reduces the overall impact of bit error rates on packet loss. However, the consequence of smaller packet size is fragmentation into more data packets and thereby dissipation of increased energy. Hence, there emerges a delicate engineering tradeoff in deciding the data packet size, where both low and high data packet size decisions lead to certain energy inefficiency issues. On the other hand, increasing transmission power level decreases packet loss probability, which is another decision variable to optimize for maximizing network lifetime. Joint consideration of these two factors exacerbates the complexity of the optimization problem for the objective of the network lifetime maximization. In this paper, we develop a realistic WSN link layer model built on top of the empirically verified energy dissipation characteristics of Mica2 motes and WSN channel models. We make use of the aforementioned link layer model to design a novel mixed integer programming (MIP) framework for the joint optimization of transmission power level and data packet size to take up the challenge introduced above. Numerical evaluations of the MIP framework with the analysis of the results over a large parameter space are performed to characterize the effects of joint optimization of packet size and power level on WSN lifetime.

Wireless sensor networks (WSNs) are envisioned to be an important enabling technology for smart grid (SG) due to the low cost, ease of deployment, and versatility of WSNs. Limited battery energy is the tightest resource constraint on WSNs. Transmission power control and data packet size optimization are powerful mechanisms for prolonging network lifetime and improving energy efficiency. Increasing transmission power will reduce the bit error rate (BER) on some links, however, utilizing the highest power level will lead to inefficient use of battery energy because on links with low path loss achieving low BER is possible without the need to use the highest power level. Utilizing a large packet size is beneficial for increasing the payload-to-overhead ratio, yet, lower packet sizes have the advantage of lower packet error rate. Furthermore, transmission power level assignment and packet size selection are interrelated. Therefore, joint optimization of transmission power level and packet size is of utmost importance in WSN lifetime maximization. In this study, we construct a detailed link layer model by employing the characteristics of Tmote Sky WSN nodes and channel characteristics based on actual measurements of SG path loss for various environments. A novel mixed integer programming framework is created by using the aforementioned link layer model for WSN lifetime maximization by joint optimization of transmission power level and data packet size. We analyzed the WSN performance by systematic exploration of the parameter space for various SG environments through the numerical solutions of the optimization model.

A study on host mobility in wide area computer networks

A wide area computer network has been installed at the Austin Hospital, Melbourne. The network consists of optic fiber segments between buildings, an ethernet spine through the main buildings and ethernet segments throughout each department. The network is connected to Internet via an ISDN link to the University of Melbourne computer network. The Austin hospital network is used for intra-hospital image distribution, external image distribution, internal and external electronic mail via Internet, electronic information access, file transfer via Internet, and remote login to Internet networked computers. Present and future developments include secure patient record access for internal users, confidential information transmission using public key encryption techniques, external dial-up connectivity for teleradiology, and research and development into medical image processing and analysis.

Wide area computer networks and scholarly communication in Regional Science

Studies of optimal packet size determination in space communication can be found in the literature. However, they are done in an analytical manner. In this paper, we present an experimental study of the cross‐layer optimal packet size for a Transmission Control Protocol (TCP) Internet Protocol (IP) enhancement, Space Communication Protocol Standards (SCPS), using a personal computer (PC)‐based testbed. We study the optimal packet size at the medium access control (MAC) layer considering the cross‐layer interactions at the physical layer. We investigate how the cross‐layer MAC packet size needs to be adjusted for optimal throughput performance based on the feedback of the bit‐error rate (BER), space‐link delay and symmetric/asymmetric channel‐rate configurations at the physical channel, and find the cross‐layer optimal packet size for the maximum throughput over the space‐Internet channels. We find that the default TCP/IP packet size of 1500 bytes for the terrestrial Internet should be chosen as the cross‐layer MAC packet size for optimal throughput performance over space channels with round‐trip time (RTT) around 250 ms and BER⩽10−6. As the channel BER at the physical layer increases, the optimal MAC packet size should be reduced to around 1000 bytes. We also find that it is more significant to have an optimal packet size for asymmetric channel than symmetric channel but the optimal packet size remains the same at a given BER for both channel ratios in our experiment. To our knowledge, this is the first paper to investigate the cross‐layer optimal MAC packet size over space‐Internet channel in the proposed approach. Copyright © 2006 John Wiley & Sons, Ltd.

Underwater Acoustic Sensor Networks offer very promising solutions to monitor the aqueous environments. Due to the distinctive characteristics of UASNs, it is very challenging to design a routing protocol that can achieve maximum data delivery ratio in the network. The main challenge is the communication medium (acoustic links) that is subject to temporary attenuation and high bit error rate (BER), which limits the throughput efficiency of the Network. Besides this, another major issue is the continuous movement of nodes due to water currents and the availability of limited resources. Due to nodes mobility distance among sensor nodes and consequently, BER varies, which have a direct impact on packet size, hence, leads to high packet loss and low data delivery ratio. To achieve a high data delivery ratio, the selection of optimal packet size is of utmost importance. Consequently, the selection of next-hop forwarding node based on optimal packet size is needed. Therefore, in this paper, we propose an adaptive routing protocol named Adaptive Packet Size Selection Based Routing (APSSR) Protocol for UASNs. APSSR determines the optimal packet size adaptively based on both varying distances between sensor nodes and BER and selects the next hop based on optimal packet size and BER. The simulation results show greater network performance in terms of Network Lifetime, Data Reception Ratio at Sink node, Average Network Delay, Packet Reception Ratio, and Packets Drop Ratio

Two MAC layer protocols are considered for multi-hop underwater acoustic networks: Pure CSMA, suitably configured to perform over a long-delay channel, and the Distance-Aware Collision Avoidance Protocol (DACAP), a protocol specifically designed for collision avoidance via a distributed coordination function à la IEEE 802.11. We investigate the impact of packet size on the performance of these two protocols. A comparative analysis, conducted via ns-2 simulations, quantifies throughput efficiency, end-to-end delay and energy-per-bit consumption as functions of the packet size. The results clearly indicate the existence of an optimal packet size for each scenario. The optimal packet size depends on the protocol characteristics, on the offered load, and is heavily influenced by the bit error rate. The results also reveal performance sensitivity to the choice of the packet size for the different protocols (CSMA and DACAP), emphasizing how a wrong selection of the packet size can result in a higher cost to performance. © 2010 IEEE.

The existence of intrusion detection systems in computer network as a part of network security tool is very important, with this tool a computer system can detect the intrusion action before it makes more damage. Traditional intrusion detection system using the rule that created by expert for detecting the intrusion, but because of the increasing of internet activity the data to be analyzed in order to establish that rules become large and create the possibility the new intrusion technique cannot detect. Using data mining techniques to find intrusion pattern from network packet data was success to detect intrusion in offline environment, but the effective intrusion detection system must able to detect the intrusion in online environment. Therefore needed a method that can be used to perform online processing of network packets data. This paper discusses the data processing network packets to establish the connection records are complete or incomplete in an effort to enabling the intrusion detection system detecting the intrusion online and based on the test result this method was success to detect the intrusion in online environment.

Background and Objective: The present issues faced by the transport systems include enormous traffic jams and congestion, unexpected road accidents, unwanted time delays, pedestrians' crossings on main roads, wastage of fuel, and many more. ITS and some other technologies work together to overcome such factors contributing to a much more desirable transport system. This paper aims to identify the security measures that could increase the security of the routing protocol and improve the performance of the DSR routing protocol. If the number of establishing links is frequently broken, then the performance of the DSR routing protocol is not very good. A new modified DSR algorithm has been designed that would help in reducing the network overhead and increase the network quality. A comparison between the performances of both algorithms has also been studied, and the results show that improved DSR routing protocol has better efficiency in parameters like end-to-end network load delays and packet delivery ratio. Methods & Materials: The paper mainly focuses on securing the Dynamic Source routing algorithm by designing its modified version and simulating it. We have Proposed Modified DSR and discussed so far that the basic functionality of the DSR algorithm, its advantages and disadvantages. The main drawbacks include the end-to-end Delay, network overhead and packet delivery ratio. Following is a modified version of the dynamic source routing algorithm, which tries to overcome all the limitations of the basic algorithm at a certain level. In the Dynamic Source Routing algorithm, the Route Maintenance phase is used for the successful propagation of the packet within the network. The nodes that are involved in the transmission acknowledge the receiving of the packet to the preceding node. Results and Discussion: The present study aims at modifying the existing algorithm and designing a new modified algorithm that has less routing overhead, less Delay in packet transmission and high network quality. Modified DSR routing algorithm is examined on the parameters like E-2-E delay, Normalize Routing Overhead, PDR. When we compare the performance of the proposed method with the Existing protocol AODV, and DSR at a number of nodes equal to 50 then we get the Proposed DSR, which has the least end-to-end Delay among all the three protocols. Conclusion: In this paper, acomparison of Exiting DSR and Modified DSR in terms of end-to-end Delay, routing load and packet delivery ratio is made. After studying the readings, the conclusion drawn was that there is less network overhead and a high delivery ratio in modified DSR as compared to the existing DSR algorithm. The corrupted and destroyed packets are detected by the receiver, and in DSR, the mobility of mobile nodes is moderate. Under certain conditions, bidirectional and unidirectional links can be accepted. DSR routing protocols are highly dependent on the parameters such as area size, packet size, packet type, and others.