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CoDel
CoDel (''Controlled Delay''; pronounced " coddle") is an active queue management (AQM) algorithm in network routing, developed by Van Jacobson and Kathleen Nichols and published as RFC8289. It is designed to overcome bufferbloat in networking hardware, such as routers, by setting limits on the delay network packets experience as they pass through buffers in this equipment. CoDel aims to improve on the overall performance of the random early detection (RED) algorithm by addressing some of its fundamental misconceptions, as perceived by Jacobson, and by being easier to manage. In 2012, an implementation of CoDel was written by Dave Täht and Eric Dumazet for the Linux kernel and dual licensed under the GNU General Public License and the 3-clause BSD license. Dumazet's improvement on CoDel is called FQ-CoDel, standing for "Fair/Flow Queue CoDel"; it was first adopted as the standard AQM and packet scheduling solution in 2014 in the OpenWrt 14.07 release called "Barrier Breaker". ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dave Täht
Dave Täht (August 11, 1965 – April 1, 2025) was an American network engineer, musician, lecturer, asteroid exploration advocate and Internet activist. He was the chief executive officer of TekLibre. Activity Täht co-founded the Bufferbloat Project with Jim Gettys, ran the CeroWrt and Make-Wifi-Fast sub-projects, and refereed the bufferbloat related mailing lists and related research activities. With a long running goal of one day building an internet with sufficiently low latency and jitter that "you could plug your piano into the wall and play with a drummer across town", he was a persistent and dedicated explainer of how queues across the internet (and wifi) really work, lecturing at MIT, Stanford, and other internet institutions such as APNIC. In the early stages of the Bufferbloat project he helped prove that applying advanced AQM and Fair Queuing techniques like (FQ-CoDel) to network packet flows would break essential assumptions in existing low priority congestion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bufferbloat
Bufferbloat is the undesirable latency that comes from a router or other network equipment buffering too many data packets. Bufferbloat can also cause packet delay variation (also known as jitter), as well as reduce the overall network throughput. When a router or switch is configured to use excessively large buffers, even very high-speed networks can become practically unusable for many interactive applications like voice over IP (VoIP), audio streaming, online gaming, and even ordinary web browsing. Some communications equipment manufacturers designed unnecessarily large buffers into some of their network products. In such equipment, bufferbloat occurs when a network link becomes congested, causing packets to become queued for long periods in these oversized buffers. In a first-in first-out queuing system, overly large buffers result in longer queues and higher latency, and do not improve network throughput. It can also be induced by specific slow-speed connections ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Active Queue Management
In routers and switches, active queue management (AQM) is the policy of dropping packets inside a buffer associated with a network interface controller (NIC) before that buffer becomes full, often with the goal of reducing network congestion or improving end-to-end latency. This task is performed by the network scheduler, which for this purpose uses various algorithms such as random early detection (RED), Explicit Congestion Notification (ECN), or controlled delay (CoDel). RFC 7567 recommends active queue management as a best practice. Overview An Internet router typically maintains a set of queues, one or more per interface, that hold packets scheduled to go out on that interface. Historically, such queues use a ''drop-tail'' discipline: a packet is put onto the queue if the queue is shorter than its maximum size (measured in packets or in bytes), and dropped otherwise. Active queue disciplines drop or mark packets before the queue is full. Typically, they operate by maintai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OpenWrt
OpenWrt (from ''open wireless router'') is an open-source project for embedded operating systems based on Linux kernel, Linux, primarily used on Embedded system, embedded devices to Router (computing), route network traffic. The main components are Linux, util-linux, musl, and BusyBox. All components have been optimized to be small enough to fit into the limited storage and memory available in home routers. OpenWrt is configured using a command-line interface (Almquist shell, ash shell) or a web interface (LuCI). There are about 8000 optional software package (installation), software packages available for installation via the opkg package management system. OpenWrt can run on various types of devices, including Customer-premises equipment, CPE routers, residential gateways, smartphones, pocket computers (e.g., Ben NanoNote). It is also possible to run OpenWrt on personal computers and laptops. History The OpenWrt project was started in 2004 after Linksys had built the firmw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
OPNsense
__NOTOC__ OPNsense is an open source, FreeBSD-based firewall and routing software developed by Deciso, a company in the Netherlands that makes hardware and sells support packages for OPNsense. Launched in 2015, it is a Fork_(software_development), fork of pfSense, which in turn was forked from m0n0wall built on FreeBSD. When m0n0wall closed down in February 2015 its creator, Manuel Kasper, referred its developer community to OPNsense. Features OPNsense has a web-based interface and can be used on the x86-64 platform. Along with acting as a firewall, it has traffic shaping, Load balancing (computing), load balancing, captive portal and virtual private network capabilities, and others can be added via plugins. The software also offers next-generation firewall capabilities utilizing Zenarmor, a NGFW plugin developed by OPNsense partner Sunny Valley Networks. Domain dispute In November 2017, a World Intellectual Property Organization panel found that Netgate, the copyright hold ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TCP Congestion Control
Transmission Control Protocol (TCP) uses a congestion control algorithm that includes various aspects of an additive increase/multiplicative decrease (AIMD) scheme, along with other schemes including slow start and a congestion window (CWND), to achieve congestion avoidance. The TCP congestion-avoidance algorithm is the primary basis for congestion control in the Internet. Per the end-to-end principle, congestion control is largely a function of internet hosts, not the network itself. There are several variations and versions of the algorithm implemented in protocol stacks of operating systems of computers that connect to the Internet. To avoid congestive collapse, TCP uses a multi-faceted congestion-control strategy. For each connection, TCP maintains a CWND, limiting the total number of unacknowledged packets that may be in transit end-to-end. This is somewhat analogous to TCP's sliding window used for flow control. Additive increase/multiplicative decrease The ad ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Buffer (telecommunication)
In computer science, a data buffer (or just buffer) is a region of memory used to store data temporarily while it is being moved from one place to another. Typically, the data is stored in a buffer as it is retrieved from an input device (such as a microphone) or just before it is sent to an output device (such as speakers); however, a buffer may be used when data is moved between process (computing), processes within a computer, comparable to buffers in telecommunication. Buffers can be implemented in a fixed memory location in hardware or by using a virtual data buffer in software that points at a location in the physical memory. In all cases, the data stored in a data buffer is stored on a computer data storage, physical storage medium. The majority of buffers are implemented in software, which typically use Random-access memory, RAM to store temporary data because of its much faster access time when compared with hard disk drives. Buffers are typically used when there is a dif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bandwidth (computing)
In computing, bandwidth is the maximum rate of data transfer across a given path. Bandwidth may be characterized as network bandwidth, data bandwidth, or digital bandwidth. This definition of ''bandwidth'' is in contrast to the field of signal processing, wireless communications, modem data transmission, digital communications, and electronics, in which ''bandwidth'' is used to refer to the signal bandwidth measured in hertz, meaning the frequency range between lowest and highest attainable frequency while meeting a well-defined impairment level in signal power. The actual bit rate that can be achieved depends not only on the signal bandwidth but also on the noise on the channel. Network capacity The term ''bandwidth'' sometimes defines the net bit rate ''peak bit rate'', ''information rate'', or physical layer ''useful bit rate'', channel capacity, or the maximum throughput of a logical or physical communication path in a digital communication system. For example, bandwi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transmission Control Protocol
The Transmission Control Protocol (TCP) is one of the main communications protocol, protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is commonly referred to as TCP/IP. TCP provides reliability (computer networking), reliable, ordered, and error detection and correction, error-checked delivery of a reliable byte stream, stream of octet (computing), octets (bytes) between applications running on hosts communicating via an IP network. Major internet applications such as the World Wide Web, email, remote administration, and file transfer rely on TCP, which is part of the transport layer of the TCP/IP suite. Transport Layer Security, SSL/TLS often runs on top of TCP. TCP is Connection-oriented communication, connection-oriented, meaning that sender and receiver firstly need to establish a connection based on agreed parameters; they do this through three-way Ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Data Buffer
In computer science, a data buffer (or just buffer) is a region of memory used to store data temporarily while it is being moved from one place to another. Typically, the data is stored in a buffer as it is retrieved from an input device (such as a microphone) or just before it is sent to an output device (such as speakers); however, a buffer may be used when data is moved between processes within a computer, comparable to buffers in telecommunication. Buffers can be implemented in a fixed memory location in hardware or by using a virtual data buffer in software that points at a location in the physical memory. In all cases, the data stored in a data buffer is stored on a physical storage medium. The majority of buffers are implemented in software, which typically use RAM to store temporary data because of its much faster access time when compared with hard disk drives. Buffers are typically used when there is a difference between the rate at which data is received and the rate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Packet-switched Network
In telecommunications, packet switching is a method of grouping data into short messages in fixed format, i.e. '' packets,'' that are transmitted over a digital network. Packets consist of a header and a payload. Data in the header is used by networking hardware to direct the packet to its destination, where the payload is extracted and used by an operating system, application software, or higher layer protocols. Packet switching is the primary basis for data communications in computer networks worldwide. During the early 1960s, American engineer Paul Baran developed a concept he called ''distributed adaptive message block switching'', with the goal of providing a fault-tolerant, efficient routing method for telecommunication messages as part of a research program at the RAND Corporation, funded by the United States Department of Defense. His ideas contradicted then-established principles of pre-allocation of network bandwidth, exemplified by the development of telecommun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
