scholarly journals Gentle Slow Start to Alleviate TCP Incast in Data Center Networks

Symmetry ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 138
Author(s):  
Sheeba Memon ◽  
Jiawei Huang ◽  
Hussain Saajid
Keyword(s):  
Data Center ◽  
State Of The Art ◽  
Transmission Control Protocol ◽  
Test Results ◽  
Data Center Networks ◽  
Congestion Window ◽  
Packet Losses ◽  
Slow Start ◽  
Time Out ◽  
Congestion Collapse

Modern data center networks typically adopt symmetric topologies, such as leaf-spine and fat-tree. When a large number of transmission control protocol (TCP) flows in data center networks send data to the same receiver, the congestion collapse, called TCP Incast, frequently happens because of the huge packet losses and Time-Out. To address the TCP Incast issue, we firstly demonstrate that adjusting the increasing speed of the congestion window during the slow start phase is crucially important. Then we propose the Gentle Slow Start (GSS) algorithm, which adjusts the congestion window according to real-time congestion state in a gentle manner and smoothly switches from slow start to congestion avoidance phase. Furthermore, we present the implementation and design of Gentle Slow Start and also integrate it into the state-of-the-art data center transport protocols. The test results show that GSS effectively decreases the Incast probability and increases the network goodput by average 8x.

scholarly journals Dynamic Congestion Control Mechanism in Mobile Adhoc Network: TCP Westwood-DCC

2020 ◽  
Vol 8 (5) ◽  
pp. 4784-4789
Keyword(s):  
Congestion Control ◽  
Control Mechanism ◽  
Transmission Control Protocol ◽  
Link Failure ◽  
Congestion Window ◽  
Slow Start ◽  
Mobile Adhoc Network ◽  
Adhoc Network ◽  
Tcp Westwood ◽  
Congestion Control Mechanism

Transmission control protocol faces a problem of packet loss differentiation in the wireless and mobile adhoc network. Congestion control is not properly done here. It cannot manage the congestion window as per type of loss and it reduces Congestion window unnecessarily and that degrades the performance. TCP Westwood cannot identify congestion or link failure loss, and it cannot manage the congestion window as per available bandwidth. This paper discusses that TCP Westwood performs bandwidth estimation, setting up a congestion window and a slow start threshold. In mobile adhoc network, link failure may happen frequently, and it should be handled properly. Link failure can be detected with the help of retransmission timeout. Once timeout occurs Westwood performs congestion avoidance. Proposed Westwood manages three states of congestion 1) Avoidance 2) congestion and 3) No congestion, it updates congestion window and slow start threshold as per the status of network. It maintains congestion window dynamically. Network status is identified by estimated bandwidth and proportionality ratio. Proposed method is tested on NS2.35 and compared with the existing TCP variants. The proposed Westwood performs optimized link utilization and congestion control mechanism. Hence it gives significant performance for loss recovery.

Balanced Multipath Transport Protocol for Mitigating MPTCP Incast in Data Center Networks

2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Mahendra Suryavanshi ◽  
Dr. Ajay Kumar ◽  
Dr. Jyoti Yadav
Keyword(s):  
Data Center ◽  
Data Centers ◽  
Window Size ◽  
Buffer Size ◽  
Data Center Networks ◽  
Congestion Window ◽  
Multipath Tcp ◽  
Multipath Transport ◽  
Multiple Paths ◽  
Multipath Transport Protocol

Recent data centers provide dense inter-connectivity between each pair of servers through multiple paths. These data centers offer high aggregate bandwidth and robustness by using multiple paths simultaneously. Multipath TCP (MPTCP) protocol is developed for improving throughput, fairly sharing network link capacity and providing robustness during path failure by utilizing multiple paths over multi-homed data center networks. Running MPTCP protocol for latency-sensitive rack-local short flows with many-to-one communication pattern at the access layer of multi-homed data center networks creates MPTCP incast problem. In this paper, Balanced Multipath TCP (BMPTCP) protocol is proposed to mitigate MPTCP incast problem in multi-homed data center networks. BMPTCP is a window-based congestion control protocol that prevents constant growth of each worker’s subflow congestion window size. BMPTCP computes identical congestion window size for all concurrent subflows by considering bottleneck Top of Rack (ToR) switch buffer size and increasing count of concurrently transmitting workers. This helps BMPTCP to avoid timeout events due to full window loss at ToR switch. Based on current congestion situation at ToR switches, BMPTCP adjust transmission rates of each worker’s subflow so that total amount of data transmitted by all concurrent subflows does not overflow bottleneck ToR switch buffer. Simulation results show that BMPTCP effectively alleviates MPTCP incast. It improves goodput, reduces flow completion time as compared to existing MPTCP and EW-MPTCP protocols.

scholarly journals Effective TCP Flow Management Based on Hierarchical Feedback Learning in Complex Data Center Network

Sensors ◽  
2022 ◽  
Vol 22 (2) ◽  
pp. 611
Author(s):  
Kimihiro Mizutani
Keyword(s):  
Reinforcement Learning ◽  
Data Center ◽  
Transmission Control Protocol ◽  
Complex Structure ◽  
Effective Bandwidth ◽  
Complex Data ◽  
Data Center Network ◽  
Data Center Networks ◽  
Flow Management ◽  
Management Scheme

Many studies focusing on improving Transmission Control Protocol (TCP) flow control realize a more effective use of bandwidth in data center networks. They are excellent ways to more effectively use the bandwidth between clients and back-end servers. However, these schemes cannot achieve the total optimization of bandwidth use for data center networks as they do not take into account the path design of TCP flows against a hierarchical complex structure of data center networks. To address this issue, this paper proposes a TCP flow management scheme specified a hierarchical complex data center network for effective bandwidth use. The proposed scheme dynamically controls the paths of TCP flows by reinforcement learning based on a hierarchical feedback model, which obtains an optimal TCP flow establishment policy even if both the network topology and link states are more complicated. In evaluation, the proposed scheme achieved more effective bandwidth use and reduced the probability of TCP incast up to 30% than the conventional TCP flow management schemes: Variant Load Balancing (VLB), Equal Cost Multi Path (ECMP), and Intelligent Forwarding Strategy Based on Reinforcement Learning (IFS-RL) in the complex data center network.

scholarly journals On Cross-Layer Interactions for Congestion Control in the Internet

2021 ◽  
Vol 11 (17) ◽  
pp. 7808
Author(s):  
Agnieszka Piotrowska
Keyword(s):  
Congestion Control ◽  
State Of The Art ◽  
Transmission Control Protocol ◽  
The Internet ◽  
Cross Layer ◽  
Transmission Control ◽  
Excellent Performance ◽  
Network Nodes ◽  
Congestion Collapse ◽  
The Impact

Two key mechanisms of the Internet are congestion control in the Transmission Control Protocol (TCP) and Active Queue Management (AQM) in routers. The former divides the bandwidth between flows and prevents the Internet from congestion collapse. Simultaneously, the latter informs hosts of the forthcoming congestion by preventive dropping of packets in network nodes. Although these two key mechanisms may severely interact with each other, they are often being researched independently, in parallel. This has led to the development of a few new congestion controls and AQM algorithms known for excellent performance under the assumption that the counterpart remains unaltered. It is unclear, however, how these new solutions in both areas interact with each other. The purpose of this paper is to fill this gap. Namely, in an extensive set of simulations, the impact of interactions between the state-of-the-art congestion control and AQM algorithms on the TCP connection performance is studied. As a result, recommendations for using some particular TCP-AQM pairs, which are observed to perform especially well, are formulated.

Analysis on Buffer Occupancy of Quantized Congestion Notification in Data Center Networks

2016 ◽  
Vol E99.B (11) ◽  
pp. 2361-2372 ◽  
Author(s):  
Chang RUAN ◽  
Jianxin WANG ◽  
Jiawei HUANG ◽  
Wanchun JIANG
Keyword(s):  
Data Center ◽  
Data Center Networks ◽  
Buffer Occupancy

Experiences in Field Testing a Variety of Aeration Equipment in Sweden and in the U.S.A. by Offgas Analysis

1989 ◽  
Vol 21 (10-11) ◽  
pp. 1421-1429
Author(s):  
D. T. Redmon ◽  
W. C. Boyle ◽  
B. G. Hellstrom
Keyword(s):  
Oxygen Transfer ◽  
State Of The Art ◽  
Field Testing ◽  
Analysis Procedure ◽  
Test Results ◽  
Transfer Testing ◽  
Parallel Tests

The background and theory of the offgas analysis procedure used in oxygen transfer testing of diffused aeration tanks is reviewed. Correlation of this method with other applicable procedures in parallel tests is reported. State-of-the-art equipment and accessories are described. Advantages of the procedure are identified, as are precautionary considerations regarding its use. Applications considered appropriate for its employment are delineated. Experience and test results in both Sweden and the U.S.A. on a variety of aeration devices are disclosed.

scholarly journals HTPC: heterogeneous traffic-aware partition coding for random packet spraying in data center networks

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiawei Huang ◽  
Shiqi Wang ◽  
Shuping Li ◽  
Shaojun Zou ◽  
Jinbin Hu ◽  
...  
Keyword(s):  
Data Center ◽  
Large Scale ◽  
Network Performance ◽  
Rooted Tree ◽  
Heterogeneous Traffic ◽  
Data Center Networks ◽  
Packet Reordering ◽  
Traffic Characteristics ◽  
Network Utilization ◽  
The Impact

AbstractModern data center networks typically adopt multi-rooted tree topologies such leaf-spine and fat-tree to provide high bisection bandwidth. Load balancing is critical to achieve low latency and high throughput. Although the per-packet schemes such as Random Packet Spraying (RPS) can achieve high network utilization and near-optimal tail latency in symmetric topologies, they are prone to cause significant packet reordering and degrade the network performance. Moreover, some coding-based schemes are proposed to alleviate the problem of packet reordering and loss. Unfortunately, these schemes ignore the traffic characteristics of data center network and cannot achieve good network performance. In this paper, we propose a Heterogeneous Traffic-aware Partition Coding named HTPC to eliminate the impact of packet reordering and improve the performance of short and long flows. HTPC smoothly adjusts the number of redundant packets based on the multi-path congestion information and the traffic characteristics so that the tailing probability of short flows and the timeout probability of long flows can be reduced. Through a series of large-scale NS2 simulations, we demonstrate that HTPC reduces average flow completion time by up to 60% compared with the state-of-the-art mechanisms.

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