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Sched.net: A Network-Aware Kubernetes Scheduler [I] - Akash Gangil & Salvatore Orlando, VMware
Sched.net: A Network-Aware Kubernetes Scheduler [I] - Akash Gangil & Salvatore Orlando, VMware
Published: 2017/04/11
Channel: Cloud Native Computing Foundation - CNCF
The Scheduler Meets the Network
The Scheduler Meets the Network
Published: 2015/08/26
Channel: MesosCon
Using the Android Job Scheduler
Using the Android Job Scheduler
Published: 2014/06/25
Channel: Google Developers
What is NETWORK SCHEDULER? What does NETWORK SCHEDULER mean? NETWORK SCHEDULER meaning
What is NETWORK SCHEDULER? What does NETWORK SCHEDULER mean? NETWORK SCHEDULER meaning
Published: 2017/03/17
Channel: The Audiopedia
Airport Network Flight Scheduler Project
Airport Network Flight Scheduler Project
Published: 2015/08/15
Channel: Nevon Projects
Network scheduler
Network scheduler
Published: 2016/01/29
Channel: WikiAudio
How to set up your ISN Online Scheduler 2017
How to set up your ISN Online Scheduler 2017
Published: 2017/01/17
Channel: Inspection Support
Create a scheduled task with Advanced Task Scheduler
Create a scheduled task with Advanced Task Scheduler
Published: 2013/02/20
Channel: SouthsoftwareTube
How Do Schedulers in Routers Work? Understanding RR, WRR, WFQ, and DRR Through Simple Examples
How Do Schedulers in Routers Work? Understanding RR, WRR, WFQ, and DRR Through Simple Examples
Published: 2016/03/10
Channel: MetanoiaInc
Open source vehicle route planning & scheduling
Open source vehicle route planning & scheduling
Published: 2014/09/10
Channel: Open Door Logistics
Automotive Workshop Scheduler Network Version
Automotive Workshop Scheduler Network Version
Published: 2013/02/06
Channel: Gabriel Lee
Network scheduler Top # 6 Facts
Network scheduler Top # 6 Facts
Published: 2015/10/28
Channel: Toral Ruchi
Project Scheduling
Project Scheduling
Published: 2014/12/02
Channel: Thayer School of Engineering at Dartmouth
Scheduling Task on Android - The easiest way
Scheduling Task on Android - The easiest way
Published: 2016/04/25
Channel: TechGuy
Network Request Scheduler Scale Testing Results
Network Request Scheduler Scale Testing Results
Published: 2012/04/24
Channel: RichReport
Setting Up Royal Flush Network Scheduler
Setting Up Royal Flush Network Scheduler
Published: 2015/02/03
Channel: iyuri305
Biosoftworld Medical Scheduler Network Setup
Biosoftworld Medical Scheduler Network Setup
Published: 2014/04/16
Channel: Biosoftworld
Link Scheduler for MTR Wireless Mesh Network
Link Scheduler for MTR Wireless Mesh Network
Published: 2015/10/15
Channel: Dinesh Lama
Resource Based Scheduling
Resource Based Scheduling
Published: 2012/12/19
Channel: Project Management Tutorials
How To Use Scheduler For Intelligent Blog Sharing Automation
How To Use Scheduler For Intelligent Blog Sharing Automation
Published: 2016/06/10
Channel: Atomic Reach
Droidcon NYC 2016 - JobScheduler is the Unavoidable Better Future
Droidcon NYC 2016 - JobScheduler is the Unavoidable Better Future
Published: 2016/11/23
Channel: touchlab
HTB Network Packet Scheduler implementation: experimenting with the new bucket size feature
HTB Network Packet Scheduler implementation: experimenting with the new bucket size feature
Published: 2017/04/26
Channel: MikroTik
Be the Best Pipeline Scheduler You Can Be | Stream Systems
Be the Best Pipeline Scheduler You Can Be | Stream Systems
Published: 2016/08/18
Channel: Stream Systems
Disabling Qos Packet Scheduler(watch it on HD)
Disabling Qos Packet Scheduler(watch it on HD)
Published: 2010/10/26
Channel: dreamprojectify
Instant Payday Network - How To Use Hootsuite Scheduler To Post
Instant Payday Network - How To Use Hootsuite Scheduler To Post
Published: 2013/03/01
Channel: Carin Petty
7 - MAC Scheduler & Physical Channels  - Fundamentals of 4G ( LTE )
7 - MAC Scheduler & Physical Channels - Fundamentals of 4G ( LTE )
Published: 2016/12/31
Channel: LTE
Social Media Auto Poster and Scheduler: How to Automatically Schedule Your Posts in WordPress
Social Media Auto Poster and Scheduler: How to Automatically Schedule Your Posts in WordPress
Published: 2017/04/03
Channel: Blog2Social
Windows Task Scheduler Overview on Windows Server 2012
Windows Task Scheduler Overview on Windows Server 2012
Published: 2013/01/26
Channel: Sachin Samy
Project management tutorial: An overview of project scheduling | lynda.com
Project management tutorial: An overview of project scheduling | lynda.com
Published: 2013/06/11
Channel: LinkedIn Learning Solutions
HD Part 2A United Airlines NOC In-Flight Crew Scheduling Flight Attendants Network Operations Center
HD Part 2A United Airlines NOC In-Flight Crew Scheduling Flight Attendants Network Operations Center
Published: 2012/12/11
Channel: ✈ Jetsetter ✈
Nova Scheduler- Optimizing, Configuring and Deploying NFV VNF
Nova Scheduler- Optimizing, Configuring and Deploying NFV VNF's on OpenStack
Published: 2017/05/10
Channel: OpenStack Foundation
delete files on a schedule in windows
delete files on a schedule in windows
Published: 2015/02/28
Channel: AllTech
Automotive Workshop Scheduler Network Version
Automotive Workshop Scheduler Network Version
Published: 2013/02/05
Channel: green baby
Direct Tweet Scheduler
Direct Tweet Scheduler
Published: 2015/03/23
Channel: Excelsier Ltd
Event Viewer Task Scheduler İlişkisi -  Network Academy - Bülent Gür
Event Viewer Task Scheduler İlişkisi - Network Academy - Bülent Gür
Published: 2014/06/17
Channel: B Salih Sonverdi
Final Year Projects 2015 | Dynamic Packet Scheduler Optimization in Wireless Relay Networks
Final Year Projects 2015 | Dynamic Packet Scheduler Optimization in Wireless Relay Networks
Published: 2015/05/23
Channel: ClickMyProject
The Race Conditions of Neutron L3 HA
The Race Conditions of Neutron L3 HA's Scheduler Under Scale Performace
Published: 2016/10/27
Channel: OpenStack Foundation
Remotely Run Programs On Another Computer (NO SOFTWARE REQUIRED)
Remotely Run Programs On Another Computer (NO SOFTWARE REQUIRED)
Published: 2013/12/24
Channel: NovaComputing
TIME TABLE SCHEDULING  USING  GENETIC    ALGORITHM
TIME TABLE SCHEDULING USING GENETIC ALGORITHM
Published: 2014/06/02
Channel: vibhanshu wadhwa
How to run batch file (especially: automatic-copy.bat) from Windows 7 task scheduler
How to run batch file (especially: automatic-copy.bat) from Windows 7 task scheduler
Published: 2013/06/08
Channel: 2nd child
Ext/Touch Scheduler + Express and Socket.IO
Ext/Touch Scheduler + Express and Socket.IO
Published: 2013/02/21
Channel: Bryntum
Spivi® Scheduler Widget and MINDBODY®
Spivi® Scheduler Widget and MINDBODY®
Published: 2015/06/29
Channel: Spivi
Error 1068: Task Scheduler cannot start [Fixed]
Error 1068: Task Scheduler cannot start [Fixed]
Published: 2013/10/14
Channel: GameHDSet
QS 139 Disable QoS Packet Scheduler
QS 139 Disable QoS Packet Scheduler
Published: 2013/02/05
Channel: thetechnologycloset
SMS scheduler, email scheduler, social network scheduler and task scheduler for Android
SMS scheduler, email scheduler, social network scheduler and task scheduler for Android
Published: 2017/04/03
Channel: Android Apps
LinuxCBT Debian 7.x - Cron Scheduler (23/72)
LinuxCBT Debian 7.x - Cron Scheduler (23/72)
Published: 2015/09/12
Channel: Tech Guru
Background work with JobScheduler (Android Development Patterns S3 Ep 12)
Background work with JobScheduler (Android Development Patterns S3 Ep 12)
Published: 2016/09/22
Channel: Android Developers
ROUND ROBIN SCHEDULING ALGORITHM
ROUND ROBIN SCHEDULING ALGORITHM
Published: 2013/03/10
Channel: Go GATE IIT
Touch Scheduler, Ext Scheduler, NodeJS + Socket IO
Touch Scheduler, Ext Scheduler, NodeJS + Socket IO
Published: 2012/12/18
Channel: Bryntum
Video 2 How to Create a Project Schedule in MS Project
Video 2 How to Create a Project Schedule in MS Project
Published: 2016/02/07
Channel: Brent Ward
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WIKIPEDIA ARTICLE

From Wikipedia, the free encyclopedia
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Packets queuing in a FIFO (first in, first out) data structure.

A network scheduler, also called packet scheduler, is an arbiter program on a node in packet switching communication network. It manages the sequence of network packets in the transmit and receive queues of the network interface controller, which is a circular data buffer. There are several network schedulers available for the different operating system kernels, that implement many of the existing network scheduling algorithms.

The network scheduler logic decides, in a way similar to statistical multiplexers,[citation needed] which network packet to forward next from the buffer. The buffer works as a queuing system, storing the network packets temporarily until they are transmitted. The buffer space may be divided into different queues, with each of them holding the packets of one flow according to configured packet classification rules; for example, packets can be divided into flows by their source and destination IP addresses. Network scheduling algorithms and their associated settings determine how the network scheduler manages the buffer.

Also, network schedulers are enabling accomplishment of the active queue management and traffic shaping.

Network scheduling algorithms[edit]

In the course of time several network scheduling algorithms (also called queueing discipline, qdisc or queueing algorithm) have been developed. Each of the scheduling algorithms used internally for these queuing disciplines provides specific reordering or dropping of network packets inside various transmit or receive buffers.[1][2] Queuing disciplines are commonly used as attempts to compensate for various networking conditions, like reducing the latency for certain classes of network packets, and are generally used as part of the quality of service (QoS) measures.[3][4][5]

Examples of algorithms suitable for managing network traffic include:

Several of the above have been implemented as Linux kernel modules[17] and are freely available.

Bufferbloat[edit]

Bufferbloat is a phenomenon in packet-switched networks generally, in which excess buffering of packets causes high latency and packet delay variation (also known as jitter), as well as reducing the overall network throughput. When a router device is configured to use excessively large buffers, even very high-speed networks can become practically unusable for many interactive applications like voice calls, chat, and even web surfing.

The CoDel algorithm attempts to reduce this problem by improving upon the RED algorithm.[citation needed] CoDel is less prone to the effects of bufferbloat than the common tail drop disciplines.[citation needed]

Terminology[edit]

  • Active queue management (AQM) – the employment of an arbiter program
  • Network traffic control – an umbrella term for all measures aimed at the control of traffic
  • Traffic shaping – a form of AQM, where the available bandwidth is being limited to match certain use cases
  • Link sharing – this term is used when more individuals or customers share the same Internet connection
  • Traffic prioritizing – a form of AQM, that selectively prioritizes certain network packets (e.g. VoIP-packets)
  • TCP Turbo – by prioritizing ACK-packets on the upload, a slow-down of the download rate of a TCP connection is prevented
  • Bandwidth management – the management of the available bandwidth

Implementations[edit]

Linux kernel[edit]

The Linux kernel's packet scheduler is part of the network stack, together with netfilter, nftables, and Berkeley Packet Filter.

The Linux kernel packet scheduler is configured using the userspace CLI utility called tc (short for "traffic control"). As the default queuing discipline, the packet scheduler uses a FIFO implementation called pfifo_fast,[18] although systemd since its version 217 changes the default queuing discipline to fq_codel.[19] The packet scheduler is an integral part of the Linux kernel's network stack and manages the ring buffers of all NICs, by working on the layer 2 of the OSI model and handling Ethernet frames, for example. It manages the transmit and receive buffers of all NICs installed in a computer.

The user space programs ifconfig and ip enable system administrators to configure the buffer sizes txqueuelen and rxqueuelen for each device separately, with their units being number of Ethernet frames regardless of their size. The Linux kernel's network stack contains several other buffers, which are not managed by the network scheduler. The overall size of all buffers has been the point of critique by the Bufferbloat project, which provided a partial solution with CoDel that has been primarily tested in OpenWrt.

Another network scheduler is being developed as part of Netfilter and nftables.[clarification needed]

eBPF was merged into the Linux kernel mainline in kernel version 3.18, and eBPF filters can also be attached to the packet scheduler's classifiers since the kernel version 4.1.[20] The eBPF functionality brought by version 4.1 of the Linux kernel extends the "classic" BPF programmable classifier by extending its scope to native eBPF code, allowing userspace to implement its own custom, safe, C-like classifiers that can be compiled using the LLVM eBPF backend and loaded into a running kernel using the tc utility.[21][better source needed]

OpenBSD[edit]

Since OpenBSD version 5.5 ALTQ was totally replaced by HFSC scheduler.

BSD[edit]

ALTQ is the implementation of a network scheduler for BSDs.

See also[edit]

References[edit]

  1. ^ "Traffic Control HOWTO: Classless Queuing Disciplines (qdiscs)". tldp.org. Retrieved November 24, 2013. 
  2. ^ Saravanan Radhakrishnan (September 30, 1999). "QoS Support in Linux: Queuing Disciplines". qos.ittc.ku.edu. Retrieved March 18, 2014. 
  3. ^ "Traffic Control HOWTO: Components of Linux Traffic Control". tldp.org. Retrieved November 24, 2013. 
  4. ^ "Traffic Control HOWTO: Traditional Elements of Traffic Control". tldp.org. Retrieved November 24, 2013. 
  5. ^ "Queuing Disciplines: Order of Packet Transmission and Dropping" (PDF). tau.ac.il. October 25, 2006. Retrieved March 18, 2014. 
  6. ^ http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.108.4477&rep=rep1&type=pdf
  7. ^ "DRR Linux kernel network scheduler module". kernel.org. Retrieved 2013-09-07. 
  8. ^ "FavorQueue: a Parameterless Active Queue Management to Improve TCP Traffic Performance" (PDF). 
  9. ^ "Heavy-Hitter Filter qdisc". kernel.org. 
  10. ^ "HTB Linux kernel network scheduler module". kernel.org. Retrieved 2013-09-07. 
  11. ^ "QFQ Linux kernel network scheduler module". kernel.org. Retrieved 2013-09-07. 
  12. ^ "Fair Queue packet scheduler committed to Linux kernel 3.12". 
  13. ^ "Network emulator Linux kernel network scheduler module". kernel.org. Retrieved 2013-09-07. 
  14. ^ "Proportional Integral controller Enhanced (PIE)". kernel.org. 
  15. ^ "SFQ Linux kernel network scheduler module". kernel.org. Retrieved 2013-09-07. 
  16. ^ "TBF Linux kernel network scheduler module". kernel.org. Retrieved 2013-09-07. 
  17. ^ "The Linux kernel network scheduler". kernel.org. 2012-12-26. Retrieved 2013-09-07. 
  18. ^ "Linux Advanced Routing and Traffic Control HOWTO, Section 9.2.1. pfifo_fast". lartc.org. 2012-05-19. Retrieved 2014-09-19. 
  19. ^ "systemd System and Service Manager: NEWS file". freedesktop.org. 2015-05-22. Retrieved 2015-06-09. 
  20. ^ "Linux kernel 4.1, Section 11. Networking". kernelnewbies.org. 2015-06-21. 
  21. ^ "Linux kernel packet scheduler#classifiers". wiki.OpenWrt.org. 

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