HAT: Heterogeneous Adaptive Throttling for On-Chip Networks

Information-centric networking (ICN) is expected to be a candidate for future internet architecture, and it supports features such as multicast that improves bandwidth utilization and transmission efficiency. However, multicast itself does not provide congestion control. When multiple multicast groups coexist, multicast traffic may exhaust all network resources, and cause network congestion and packet loss. Additionally, traditional IP multicast congestion control mechanisms cannot be directly applied to ICN architecture. Therefore, it is necessary to consider an effective congestion control mechanism for ICN multicast. This paper proposes a single-rate multicast congestion control mechanism, called SRMCC. It supports router-assisted awareness of the network congestion state and congestion control message aggregation. Moreover, the fair shared rate estimation method is innovatively proposed to achieve protocol fairness. Most importantly, it adjusts the rate according to different congestion states indicated by the queue occupancy ratio. By introducing a rate selection factor, it can achieve a balance between packet loss rate and throughput. Experimental results show that our proposal outperforms other mechanisms in throughput, packet loss rate, total bandwidth utilization, and overhead, and achieves protocol fairness and better TCP friendliness.

Bufferless Network-on-Chip (NoC) emerges as an interesting option for NoC design in recent years, which can save considerable router power and area. However, bufferless NoC only works well under low-to-medium load because it becomes more easily congested as message injection rate increases. In this paper, we propose a novel distributed source-throttling congestion control mechanism that relieves the effect of congestion in bufferless NoC under high load, called Cbufferless. The proposed strategy uses a novel congestion detection and control mechanism, computing average deflection rate of routing flit and distributed throttling message injection. Utilizing the new mechanism, the congestion information can be directly obtained inside node, which allows the mechanism to be fully distributed without requiring any transmission of global congestion information among neighbor routers and within a router. Simulation results show that the proposed mechanism improves system throughput by up to $$\sim $$ ~ 30 and $$\sim $$ ~ 15.5 %, saves energy consumption by up to $$\sim $$ ~ 40 and $$\sim $$ ~ 19 % than that of baseline and injection rate throttling bufferless NoCs, respectively, and keeps lower message latency under congested load when compared.

TCP (Transmission Control Protocol) is the most used transport protocol for wired and wireless networks. It provides many services (reliability, end to end delivery ...) to the applications running over the Internet, but to be able to manage traffics with a huge quantity of data, TCP must have robust congestion control mechanisms. Many researchers have agreed that despite the existence of some congestion control algorithms, TCP still suffers from disappointing performances for short and long flows. For that, researches are still launched by the network community in order to have the suitable mechanism ensuring fair and efficient bandwidth allocation. The works already carried out in this subject has elaborated several congestion control mechanisms. In this paper, we discuss, identify, analyze and compare the behavior of some congestion control mechanisms under congested wireless mech networks, in order to identify their advantages and their respective limits. For the simulation, we used the well known network simulator ns2. Simulation results show that TCP Tahoe, TCP Reno, TCP New Reno, Sack are loss-based, they are beneficial for latency-sensitive flows, while TCP Vegas which is delay-based, it is recommended for applications that don't endure the loss of information but suffers from fairness problems when sharing a bottleneck with competitive flows.

Many smart healthcare centers are deploying long distance, high bandwidth networks in their computer network infrastructure and operation. Transmission control protocol (TCP) is responsible for reliable and secure communication of data in these medial infrastructure networks. TCP is reliable and secure due to its congestion control mechanism, which is responsible for detecting and reacting to the congestion in the network. Many TCP congestion control mechanisms have been developed previously for different operating systems. TCP CUBIC, TCP Compound, and TCP Fusion are the default congestion control mechanism in Linux, Microsoft Windows, and Sun Solaris operating systems, respectively. The earliest congestion control mechanism Standard TCP acts as the trademark congestion control mechanism. The exponential growth of congestion window ( $cwnd$ ) in slow start phase of the TCP CUBIC causes burst losses of packets, and TCP flows did not share available link bandwidth fairly. The prime aim of this paper is to enhance the performance of TCP CUBIC for long distance, high bandwidth secured networks to achieve better performance in medical infrastructure, concerning packet loss rate, protocol fairness, and convergence time. In this paper, congestion control module for slow start is proposed, which reduces the effect of the exponential growth of $cwnd$ by designing the new limits of $cwnd$ size in slow start phase, which in turn decreases the packet loss rate in healthcare networks. NS-2 is used to simulate the experiments of enhanced TCP CUBIC and state-of-the-art congestion control mechanisms. Results show that the performance of enhanced TCP CUBIC outperforms by 18% as compared with the state-of-the-art congestion control mechanisms.

In this chapter, layer-2 hop-by-hop congestion control mechanisms for wireless mesh networks are studied. First, background on development of congestion control as a research area is presented. Then, congestion is defined and the causes of congestion in a mesh network are identified. The steps and challenges for development of a congestion control protocol are explored by dividing congestion control mechanism into three main functions: congestion detection, signaling, and resolution. Stability and fairness in the context of rate control are studied, and global stability in the presence of delay is identified as the main challenge faced by hop-by-bop congestion control algorithms in multihop networks. The congestion control framework in the IEEE 802.11 draft standard on mesh networking is then presented. The chapter concludes with thoughts for practitioners and areas for future research in this field.

Delay Tolerant Network (DTN) shows some features like link frequent interruptions, long delays, limited resources and so on, while nodes fight each other to win the network resources in the process of communication, which can lead to network congestion in delay tolerant network. Therefore, congestion control is a key issue in delay tolerant network research. The present congestion control strategies are divided into congestion detection, congestion avoidance, congestion handling. In this paper, we qualitatively analyze and compare typical congestion control strategies have been proposed, which are based on the analysis of the basic characteristics of the delay tolerant network. Through the analysis of the advantages and disadvantages of each mechanism, we conducted further research and discovery. Finally, we make a conclusion and propose congestion control technology and the energy constraint balance strategy.

In wireless multimedia sensor networks (WMSNs) a sensor node may have different types of sensor which gather different kinds of data. To support quality of service (QoS) requirements for multimedia applications having a reliable and fair transport protocol is necessary. One of the main objectives of the transport layer in WMSNs is congestion control. We observe that the information provided may have different levels of importance and argue that sensor networks should be willing to spend more resources in disseminating packets carrying more important information. In WMSN event-driven applications, it is critical to report the detected events in the area, resulting in sudden bursts of traffic due to occurrence of spatially-correlated or multiple events, causing loss of data. Also, nodes have very limited power due to hardware constraints. Packet losses and retransmissions resulting from congestion, cost precious energy and shorten the lifetime of sensor nodes. Till now, in WMSNs, Congestion control techniques are based on detection of congestion and recovery, but they cannot eliminate or prevent the occurrence of congestion. Collision is a symptom of congestion in the wireless channel and can result in a time-variant channel capacity. The main intention of this protocol is to be used as a mechanism for reducing congestion in the network by free resources to set accurate rates and priority data needs. If two nodes send their packets in the shortest path to the parent node in a crowded place, a source node must prioritize the data and uses data that have lower priorities of a suitable detour nodes consisting of low or non- active consciously. Proposed algorithm is applied to the nodes near the base station (which convey more traffic) after the congestion detection mechanism detected the congestion. The results obtained from simulation test done by NS-2 simulator indicate that the proposed model is more innovative and presents better performance in compare with CCF, PCCP and DCCP protocols.

Congestion control enables network nodes to adopt certain approaches to avoid network congestion as much as possible, and respond when network congestion occurs. BBR is a transmission rate-based congestion control algorithm proposed by Google for Chromium QUIC and Linux kernel deployment. The new transmission protocol QUIC proposed by Google has a better congestion control mechanism than TCP. Based on the existing BBR congestion control algorithm, this paper proposes the IBCCA congestion control algorithm and evaluates the performance of the IBCCA, CUBIC, and BBR algorithms under the QUIC protocol in wireless LAN. When the network traffic burst flow is small or the burst duration is short, IBCCA achieves higher network goodput and lower transmission round-trip time. In the experiment of multi-stream transmission, the IBCCA algorithm achieves higher fairness while the good-put and RTT are at the same level. The BBR algorithm achieves a smaller RTT, and the goodput of the IBCCA algorithm is not much different from the CUBIC algorithm.

General purpose chip multiprocessors (CMP) are challenging to on-chip intercommunication network designers since one would need low latency, high bandwidth independently of the communication patterns, support for cost-efficient synchronization, and low energy consumption to support arbitrary applications. Currently popular ring-based networks provide straight-forward design, far superior performance than bus-based alternatives and extensibility over crossbars. As the number of processors cores increases, however, the effective bandwidth between most parts of a ring remains constant implying higher capacity solutions are needed to support scaled-up CMPs. In this paper we describe the on-chip network of our REPLICA CMP. It is based on an acyclic bandwidth-scaled multi-mesh topology and uses routing with elastic synchronization mechanism. To avoid congestion and hot spots in shared memory access traffic can be randomized with a programmable hashing function. The performance of the network is evaluated preliminarily on our experimental 4-core and 16-core REPLICA FPGA implementations and REPLICA simulator.

Interactive and delay-sensitive applications constitute an important and growing part of the Internet. Today, low delays can only be achieved if there are no congested links along the path. At a bottleneck, the commonly used congestion control mechanisms induce high queuing delay and packet loss. Specialized congestion control mechanisms achieving a low queuing delay in an otherwise congested network exist. However, if their flows share a bottleneck with traditionally congestion controlled flows, they get suppressed or loose their low-delay property. This paper presents three approaches - Separate Paths, Separate Queues and Limited Queue - that enable coexistence of congestion control mechanisms that are optimized for different goals, e.g., interactive applications and bulk transfers. The measurement results show that concurrent operation of different congestion control mechanisms can be successfully implemented this way.

Maintaining the performance of reliable transport protocols, such as transmission control protocol (TCP), over wireless mesh networks (WMNs) is a challenging problem due to the unique characteristics of data transmission over WMNs. The unique characteristics include multi-hop communication over lossy and non-deterministic wireless mediums, data transmission in the absence of a base station, similar traffic patterns over neighboring mesh nodes, etc. One of the reasons for the poor performance of conventional TCP variants over WMNs is that the congestion control mechanisms in conventional TCP variants do not explicitly account for these unique characteristics. To address this problem, this paper proposes a novel artificial intelligence based congestion control technique for reliable data transfer over WMNs. The synergy with artificial intelligence is established by exploiting a carefully designed neural network (NN) in the congestion control mechanism. We analyze the proposed NN based congestion control technique in detail and incorporate it into TCP to create a new variant that we name as intelligent TCP or iTCP. We evaluate the performance of iTCP using both ns-2 simulations and real testbed experiments. Our evaluation results demonstrate that our proposed congestion control technique exhibits a significant improvement in total network throughput and average energy consumption per transmitted bit compared to the congestion control techniques used in other TCP variants.

Evaluation Scheme for NoC-based CMP with Integrated Processor Management SystemWith the opportunities and benefits offered by Chip Multiprocessors (CMPs), there are many challenges that need to be addressed in order to exploit the full potential of CMPs. Such aspects as parallel programs, interconnection design, cache arrangement and on-chip cores allocation become a limiting factor. To ensure validity of approaches and research, we propose an evaluation system for CMPs with Network-on-Chip (NoC) and processor management system integrated on one die. The suggested experimentation system is described in details. The proposed system that is used for tests and results of the experiments are presented and discussed. As decision making criteria, we consider energy efficiency of Processor Allocator (PA) and NoC, as well as NoC traffic characteristic (load balance). In order to improve the system understanding, brief overview on most important NoC and PA architectures is also presented. Analyzed results reveal that CMP with a PA controlled by IFF allocation algorithm for mesh systems and torus-based NoC driven by DORLB routing with express-virtual-channel flow control achieved the best traffic balance and energy characteristic.

A congestion control mechanism is needed to balance the network load to prevent pack drops and avoid network deadlocks. The main purpose is to analyze efficient and reliable congestion control methods which will reduce the weaknesses in various existing congestion control methods and propose a framework to minimize the gateway congestion in the network. As the demand of heterogeneous users of computer network day by day dynamically and rapidly changing in many aspects, grounded on the application situations our congestion control mechanism functions well in the situations that occur in Internet. The maximum degree of dynamics can be handle efficiently by keeping the generality of its existing end-to-end solution in our congestion control design.

This document describes a possible congestion control mechanism for acknowledgement traffic (ACKs) in TCP. The document specifies an end- to-end acknowledgement congestion control mechanism for TCP that uses participation from both TCP hosts, the TCP data sender and the TCP data receiver. The TCP data sender detects lost or ECN-marked ACK packets, and tells the TCP data receiver the ACK Ratio R to use to respond to the congestion on the reverse path from the data receiver to the data sender. The TCP data receiver sends roughly one ACK packet for every R data packets received. This mechanism is based on the acknowledgement congestion control in DCCP's CCID 2. This acknowledgement congestion control mechanism is being specified for further evaluation by the network community.

In Named Data Networking (NDN), content can be retrieved from multiple sources through multiple path, which makes the traditional end-to-end congestion control mechanisms unsuitable for NDN. A lot of works have been done to achieve the congestion control by limiting the transmission rate of interest packets, but most of them overlooked the intelligent forwarding feature in NDN. In this paper, we propose a ratebased, multipath-aware congestion control algorithm MNRCP, which is inspired by Rate Control Protocol (RCP). MNRCP calculates the transmission rate for every flow and feedbacks it to the consumer to control the sending rate of interest packets. In order to fully exploit the features of multiple data sources, in-network caching and multipath forwarding and adapt to the practical scenarios that interest packets requesting the same data can arrive from different interfaces, we propose a novel multipath forwarding strategy and a multipath feedback mechanism to achieve fairness and network utilization. In addition, simulation results of our algorithm in ndnSIM2.3 show that compared with other congestion control mechanisms, MNRCP can achieve higher total throughput while ensuring fairness. According to the available bandwidth of the path, MNRCP also can achieve the optimal traffic split ratio, and thus performs better in load balancing.