Packet Dropping Policy Research Articles

Reliable packet transmission in WBAN with dynamic and optimized QoS using multi-objective lion cooperative hunt optimizer

Recent studies demonstrate that handling a patient’s health-related data needs dynamic Quality of Service (QoS) to cope up with significant changes in the functioning of a Patient Monitoring Wireless Body Area Network (PA-WBAN). This kind of system demands a remarkable improvement in the QoS as it is dealing with the reliable transmission of a large volume of assorted data in a frequently changing environment. The QoS in a PA-WBAN is not only about how it senses or reads data from various body parts but is how it deciphers the sensed data. In the patient monitoring system, if the required data is not available in a readable format or not in a specific time, then this data becomes useless and is of no use. However, to harmonize these requirements, two approaches are proposed in this paper. The first protocol is developed for obtaining dynamic QoS for reliable packet transmission. It offers both node and packet-level dynamic-priority assignment policy, which further helps in fair and dynamic resource allocation, queuing, scheduling, retransmission, drop, and delay. It provides fair queuing and percentile scheduling policies, which estimates service rate for each priority queue and serves only highly significant packets with high waiting time during scheduling. Additionally, it offers application-specific reliability through a predictive retransmission and loss recovery policy. During retransmission and loss recovery, it calculates a retransmission rate for each sensor node and retransmits only that amount of packets from each sensor node. It also controls congestion with its dynamic priority-based rate adjustment and packet drop policies. It further provides a concept of time-bound based packet transmission policy that minimizes delay and jitter more appropriately. The second protocol is designed for attaining optimized QoS in the dynamic and assorted PA-WBAN. It applies a Lion Cooperative Hunt Optimization (LCHO) technique for the optimization of multi-objective QoS. Both theoretical and simulation results examine the usefulness of the proposed protocols and illustrate its advantage over the existing protocols.

Cross-Layer Optimization & VGALA Structure for 5G Grid

Heterogeneous cloud radio access network (HCRAN) promises higher energy efficiency (EE) than the conservative cellular networks by centralizing the baseband signal processing into the baseband unit (BBU) pool hosted by cloud computing platforms. In existing energy-efficient networking mechanisms designed for conservative cellular networks cannot fully leverage the parameters like latency, load balancing, power consumption and the network energy consumption. In this work ,Cross-layer based VGALA optimization structure is proposed which endeavours a balance between network utilities. The average traffic delivery latency, green energy utilization are techniques used to optimize the packet dropping policy, power allocation policy and bandwidth allocation policy to minimize the transmit power under the QoS constraint. The optimal solution is obtained, depends upon both channel and queue state information. The final result show that recommended framework empowers an adaptable trade off among the on grid power consumption and the normal traffic latency. And finally saves a significant amount of on-grid power and the optimal solution obtained depends on both channel and queue state information. It also shows that setting the three packet loss probabilities as equal causes marginal power loss caused in H-CRAN design.

Cross-Layer Optimization for Ultra-Reliable and Low-Latency Radio Access Networks

In this paper, we propose a framework for cross-layer optimization to ensure ultra-high reliability and ultra-low latency in radio access networks, where both transmission delay and queueing delay are considered. With short transmission time, the blocklength of channel codes is finite, and the Shannon capacity cannot be used to characterize the maximal achievable rate with given transmission error probability. With randomly arrived packets, some packets may violate the queueing delay. Moreover, since the queueing delay is shorter than the channel coherence time in typical scenarios, the required transmit power to guarantee the queueing delay and transmission error probability will become unbounded even with spatial diversity. To ensure the required quality-of-service (QoS) with finite transmit power, a proactive packet dropping mechanism is introduced. Then, the overall packet loss probability includes transmission error probability , queueing delay violation probability , and packet dropping probability . We optimize the packet dropping policy, power allocation policy, and bandwidth allocation policy to minimize the transmit power under the QoS constraint. The optimal solution is obtained, which depends on both channel and queue state information. Simulation and numerical results validate our analysis, and show that setting the three packet loss probabilities as equal causes marginal power loss.

An Emergency Adaptive Communication Protocol for Driver Health Monitoring in WSN Based Vehicular Environments

Driver health and activity monitoring is one of the principal design issues for the safety provision in vehicular environments. Recently, the wireless sensor network technology is widely used to address the concerns in such applications. However, only few conventional protocols have dealt with reliable and prompt delivery of emergency packets considering the vehicular specifications. In this paper, we propose an emergency adaptive communication protocol, which treats the data packet in a discriminatory manner by investigating whether it is emergency or not. Hence, the proposed protocol defines an emergency factor for each data packet and exploits it for both route establishment and channel access procedures. In route establishment, the proposed protocol chooses a route with low delay and high reliability among the candidates by periodic calculation of emergency factor. Then, it dynamically adjusts back-off parameters before participating in the channel contention among the neighbors. In addition, an emergency aware queue management scheme and packet drop policy are proposed to improve the reliability of emergency data traffic during transmission. Our simulation results show that the proposed protocol provides a better performance compared with the existing protocol in terms of packet delivery ratio, end-to-end packet delay, and number of dropped packets.

Receiver-Based Flow Control for Networks in Overload

We consider utility maximization in networks where the sources do not employ flow control and may consequently overload the network. In the absence of flow control at the sources, some packets will inevitably have to be dropped when the network is in overload. To that end, we first develop a distributed, threshold-based packet-dropping policy that maximizes the weighted sum throughput. Next, we consider utility maximization and develop a receiver-based flow control scheme that, when combined with threshold-based packet dropping, achieves the optimal utility. The flow control scheme creates virtual queues at the receivers as a push-back mechanism to optimize the amount of data delivered to the destinations via back-pressure routing. A new feature of our scheme is that a utility function can be assigned to a collection of flows, generalizing the traditional approach of optimizing per-flow utilities. Our control policies use finite-buffer queues and are independent of arrival statistics. Their near-optimal performance is proved and further supported by simulation results.

Performance Evaluation of Quality of Service for Joint Packet Dropping and Scheduling

Quality of Service is particularly necessary to serve delay-sensitive applications in heavy-loaded wireless networks. In this paper we evaluate a strategy of combining packet dropping and scheduling policies at Medium Access Control layer in guaranteeing maximum packet latency for real-time applications. The purpose of this work is to evaluate how significance the mentioned combination schemes can meet the required latency and also the achievable system throughput. For the case study, a real time Polling Service class in the Worldwide Interoperability for Microwave Access System for downlink transmission is assumed. The main analysis is undertaken for User Datagram Protocol (UDP) traffic in stationary and mobile user scenarios under heavy load conditions, and the impact of mixed Transmission Control Protocol and UDP traffic is also investigated. Results show that the introduction of a packet dropping policy ensures that the latency is kept well within the required maximum latency requirement, regardless of the types of scheduler used. However, the packet drop percentage (or packet loss) depends strongly on the types of schedulers. All schedulers show similar goodput performance for low load conditions, and the results can only be distinguished for the cases of heavy load/overloaded conditions.

A Study of the Correlations Between Channel and Traffic Statistics in Multihop Networks

This paper investigates the correlations between traffic statistics and channel qualities and their impact on the performance of multihop networks. The physical channel is characterized by the probability of successful reception, which depends on the multiple access interference (MAI). Since a node contributes to interference only if it has a nonempty buffer upon being scheduled, the MAI is determined not only by the media-access-control (MAC) scheme but also by the traffic statistics. Therefore, the physical channel performance is intertwined with both the MAC scheme and the traffic statistics. We discuss the autocorrelation in the channels themselves and the cross correlation between the channel and traffic rates and derive closed-form expressions for the network throughput and capacity for -phase time division multiple access (TDMA) and slotted ALOHA. We also find that, in addition to the traffic rate, the traffic burstiness and correlation have a significant influence on . For smooth traffic, even without the MAC control, the traffic correlation could induce optimal spatial reuse like TDMA without the overhead of establishing and maintaining the frame structure. For bursty traffic, we propose an approach that employs a packet dropping policy and takes advantage of the traffic correlation to form a similar natural spacing as for smooth traffic.

FlowMate: scalable on-line flow clustering

We design and implement an efficient on-line approach, FlowMate, for clustering flows (connections) emanating from a busy server, according to shared bottlenecks. Clusters can be periodically input to load balancing, congestion coordination, aggregation, admission control, or pricing modules. FlowMate uses in-band (passive) end-to-end delay measurements to infer shared bottlenecks. Delay information is piggybacked on feedback from the receivers, or, if impossible, TCP or application round-trip time estimates are used. We simulate FlowMate and examine the effects of network load, traffic burstiness, network buffer sizes, and packet drop policies on clustering correctness, evaluated via a novel accuracy metric. We find that coordinated congestion management techniques are more fair when integrated with FlowMate. We also implement FlowMate in the Linux kernel v2.4.17 and evaluate its performance on the Emulab testbed, using both synthetic and tcplib-generated traffic. Our results demonstrate that clustering of medium to long-lived flows is accurate, even with bursty background traffic. Finally, we validate our results on the Internet Planetlab testbed.

Application performance and service differentiation for best effort traffic in ATM networks

Best effort services continue to be simple and cheap and one of the most widely used networking services. For this class of service the network provides no QoS guarantees and applications compete with each other to gain the network resources they need. In this environment, the Packet Dropping Policy (PDP) is the most important and influential mechanism. PDPs can improve the application performance and the network utilization, achieve fairness among the competing connections, isolate traffic, and even provide service predictability and traffic differentiation. Although there are many Selective Packet Dropping mechanisms for the ATM Unspecified Bit Rate (UBR) service category, there is no single and best policy yet. All of them have advantages and disadvantages and finding a good policy for all scenarios is not easy. In this article we present a flexible PDP called Preemptive Partial Packet Discard (pPPD) that provides better application performance and network utilization than current alternatives. In addition, we demonstrate the flexibility of pPPD proposing four pPPD variants including pPPD-DS, meant to enhance the best effort service and provide relative traffic differentiation. pPPD-DS is proposed as a mechanism to implement the Behaviour Classes recently approved by the ATM Forum in the Differentiated UBR traffic management specifications for the support of the IETF Differentiated Model over ATM networks.

Avoiding congestion collapse on the Internet using TCP tunnels

This paper discusses the application of TCP tunnels on the Internet and how Internet traffic can benefit from the congestion control mechanism of the tunnels. Primarily, we show the TCP tunnels offer TCP-friendly flows protection from TCP-unfriendly traffic. TCP tunnels also reduce the many flows situation on the Internet to that of a few flows. In addition, TCP tunnels eliminate unnecessary packet loss in the core routers of the congested backbones, which waste precious bandwidth leading to congestion collapse due to unresponsive UDP flows. We finally highlight that the use of TCP tunnels can, in principle, help prevent certain forms of congestion collapse described by Floyd and Fall [IEEE/ACM Trans Networking 7 (4) (1999) 458]. The deployment of TCP tunnels on the Internet and the issues involved are also discussed and we conclude that with the recent RFC2309 recommendation of using random early drop as the default packet-drop policy in Internet routers, coupled with the implementation of a pure tunnel environment on backbone networks makes the deployment of TCP tunnels a feasible endeavour worthy of further investigation.

Routing stability in congested networks

Loss of the routing protocol messages due to network congestion can cause peering session failures in routers, leading to route flaps and routing instabilities. We study the effects of traffic overload on routing protocols by quantifying the stability and robustness properties of two common Internet routing protocols, OSPF and BGP, when the routing control traffic is not isolated from data traffic. We develop analytical models to quantify the effect of congestion on the robustness of OSPF and BGP as a function of the traffic overload factor, queueing delays, and packet sizes. We perform extensive measurements in an experimental network of routers to validate the analytical results. Subsequently we use the analytical framework to investigate the effect of factors that are difficult to incorporate into an experimental setup, such as a wide range of link propagation delays and packet dropping policies. Our results show that increased queueing and propagation delays adversely affect BGP's resilience to congestion, in spite of its use of a reliable transport protocol. Our findings demonstrate the importance of selective treatment of routing protocol messages from other traffic, by using scheduling and utilizing buffer management policies in the routers, to achieve stable and robust network operation.

Packet dropping policies for ATM and IP networks

Selective packet dropping policies have been used to reduce congestion and transmission of traffic that would inevitably be retransmitted. For data applications using best-effort services, packet dropping policies (PDPs) are congestion management mechanisms implemented at each intermediate node that decide, reactively or proactively, to drop packets to reduce congestion and free up precious buffer space. While the primary goal of PDPs is to avoid or combat congestion, the individual PDP designs can significantly affect application throughput, network utilization, performance fairness, and synchronization problems with multiple transmission control protocol (TCP) connections. Scalability and simplicity are also important design issues. This article surveys the most important selective packet dropping policies that have been designed for best-effort traffic in ATM and IP networks, providing a comprehensive comparison between the different mechanisms.