Quality of service (QoS) is the description or measurement of the overall performance of a service, such as a telephony or computer network or a cloud computing service, particularly the performance seen by the users of the network. To quantitatively measure quality of service, several related aspects of the network service are often considered, such as packet loss, bit rate, throughput, transmission delay, availability, jitter, etc.
The Real-time Transport Protocol (RTP) is a network protocol for delivering audio and video over IP networks. RTP is used in communication and entertainment systems that involve streaming media, such as telephony, video teleconference applications including WebRTC, television services and web-based push-to-talk features.
In general terms, throughput is the rate of production or the rate at which something is processed.
The data link layer, or layer 2, is the second layer of the seven-layer OSI model of computer networking. This layer is the protocol layer that transfers data between nodes on a network segment across the physical layer. The data link layer provides the functional and procedural means to transfer data between network entities and may also provide the means to detect and possibly correct errors that can occur in the physical layer.
Link-state routing protocols are one of the two main classes of routing protocols used in packet switching networks for computer communications, the other being distance-vector routing protocols. Examples of link-state routing protocols include Open Shortest Path First (OSPF) and Intermediate System to Intermediate System (IS-IS).
In IEEE 802 LAN/MAN standards, the medium access control sublayer is the layer that controls the hardware responsible for interaction with the wired, optical or wireless transmission medium. The MAC sublayer and the logical link control (LLC) sublayer together make up the data link layer. Within the data link layer, the LLC provides flow control and multiplexing for the logical link, while the MAC provides flow control and multiplexing for the transmission medium.
Network congestion in data networking and queueing theory is the reduced quality of service that occurs when a network node or link is carrying more data than it can handle. Typical effects include queueing delay, packet loss or the blocking of new connections. A consequence of congestion is that an incremental increase in offered load leads either only to a small increase or even a decrease in network throughput.
A wireless mesh network (WMN) is a communications network made up of radio nodes organized in a mesh topology. It can also be a form of wireless ad hoc network.
The Optimized Link State Routing Protocol (OLSR) is an IP routing protocol optimized for mobile ad hoc networks, which can also be used on other wireless ad hoc networks. OLSR is a proactive link-state routing protocol, which uses hello and topology control (TC) messages to discover and then disseminate link state information throughout the mobile ad hoc network. Individual nodes use this topology information to compute next hop destinations for all nodes in the network using shortest hop forwarding paths.
Connection-oriented communication is a network communication mode in telecommunications and computer networking, where a communication session or a semi-permanent connection is established before any useful data can be transferred, enabling the ability to ensure that data is delivered in the correct order to the upper communication layer. The alternative to connection-oriented transmission is connectionless communication, for example the datagram mode communication used by the IP and UDP protocols, where data may be delivered out of order, since different network packets are routed independently, and may be delivered over different paths.
The Hazy-Sighted Link State Routing Protocol (HSLS) is a wireless mesh network routing protocol being developed by the CUWiN Foundation. This is an algorithm allowing computers communicating via digital radio in a mesh network to forward messages to computers that are out of reach of direct radio contact. Its network overhead is theoretically optimal, utilizing both proactive and reactive link-state routing to limit network updates in space and time. Its inventors believe it is a more efficient protocol to route wired networks as well. HSLS was invented by researchers at BBN Technologies.
Packet loss occurs when one or more packets of data travelling across a computer network fail to reach their destination. Packet loss is either caused by errors in data transmission, typically across wireless networks, or network congestion. Packet loss is measured as a percentage of packets lost with respect to packets sent.
Network coding is a field of research founded in a series of papers from the late 1990s to the early 2000s. However, the concept of network coding, in particular linear network coding, appeared much earlier. In a 1978 paper, a scheme for improving the throughput of a two-way communication through a satellite was proposed. In this scheme, two users trying to communicate with each other transmit their data streams to a satellite, which combines the two streams by summing them modulo 2 and then broadcasts the combined stream. Each of the two users, upon receiving the broadcast stream, can decode the other stream by using the information of their own stream.
In wireless networking, On-Demand Multicast Routing Protocol is a protocol for routing multicast and unicast traffic throughout Ad hoc wireless mesh networks.
Smodem refers to a bidirectional protocol for file transfer used between modems and the DOS program in which the protocol is implemented, both of which were developed by a Finnish company named Arisoft. It was mainly used in bulletin board systems because it could transfer files in both directions at the same time and allowed users to chat with each other with AriSoft's GroupChat software. Other popular bidirectional protocols such as BiModem, HS/Link and HydraCom also offered a chat option with the operator, but not with the system's other users.
Roofnet was an experimental 802.11b/g mesh network developed by the Computer Science and Artificial Intelligence Laboratory at the Massachusetts Institute of Technology (MIT). Research included link-level measurements of 802.11, finding high-throughput routes in the face of lossy links, link adaptation, and developing new protocols which take advantage of radio’s unique properties (ExOR). The software developed for this project is available free as open source.
The Better Approach to Mobile Ad-hoc Networking (B.A.T.M.A.N.) is a routing protocol for multi-hop mobile ad hoc networks which is under development by the German "Freifunk" community and intended to replace the Optimized Link State Routing Protocol (OLSR).
A wide variety of different wireless data technologies exist, some in direct competition with one another, others designed for specific applications. Wireless technologies can be evaluated by a variety of different metrics of which some are described in this entry.
IEEE 802.11s is a wireless LAN standard and an IEEE 802.11 amendment for mesh networking, defining how wireless devices can interconnect to create a wireless LAN (WLAN) mesh network, which may be used for relatively fixed topologies and wireless ad hoc networks. The IEEE 802.11s task group drew upon volunteers from university and industry to provide specifications and possible design solutions for wireless mesh networking. As a standard, the document was iterated and revised many times prior to finalization.
The Collection Tree Protocol (CTP) is a routing protocol for wireless sensor networks. It is used for transferring data from one or more sensors to one or more root nodes.
