A measure of the quality, or lack thereof, of the voice and video delivered over different networks. In voice, it measures whether or not the spoken word is delivered “instantly” from one phone to another. From an engineering standpoint, it is a measure of the delay or latency in the signal. In the case of the public switched telephone network, there is little or no perceived latency. An engineer would therefore say “there is QoS” with the telephone network. In IP-based networks, there is often latency and therefore the voice signal is delayed from one person’s lips to the recipient’s ears. In video, the lack of quality of service causes the transmission of the images to be delayed. An engineer would therefore say “there is no QoS” in those networks. Manufacturers of teleconferencing equipment do provide solutions to add what is called “guaranteed Quality of Service” so that there is little perceived latency, even in a packet or IP network. For a somewhat comical definition of Quality of Service, see the comments of Madge Network’s Nigel Terry on page one of the May 26,1997 edition of TeleSpan. :: X Y Z : Home : Guide TOC

Enables Wi-Fi access points to prioritize traffic and optimize the way shared network resources are allocated among different applications. Without QoS, all applications running on different devices have equal opportunity to transmit data frames. That works well for data traffic from applications such as file transfers or e-mail, but it is inadequate for multimedia applications. QoS is required for multimedia applications (such as VoIP, video streaming, and interactive gaming), which are highly sensitive to latency increases and throughput reductions. (See also: 802.11e, WMM)

QoS provides the means to guarantee a certain level of a specified resource to selected traffic on a network. Quality can be defined as e.g. a maintained level of bandwidth, low latency, no packet losses, etc. The QoS in Axis network video products marks the data packets for various types of network traffic originating from the product. This makes it possible for network routers and switches to e.g. reserve a fixed amount of bandwidth for these types of traffic.

This is a networking term which may be used in one of two ways. In the first way, it represents a quality of networking. In the second, referred to usually as "QoS", it represents a guarantee or commitment to not only a particular quality of network service but also a particular rate or minimum rate of data delivery, as well as maximum times between packets of data. Used where applications are sensitive to delays, such as video conferencing. Initially a feature of ATM, it is now being incorporated into the TCP/IP protocol and will eventually be available as a service on non-ATM networks. A statement that QoS is is provided is distinct from one which says QoS guarantees are provided. UCInet provides a good quality of service, but not QoS guarantees as part of Basic Network Services.

Measure of performance for a transmission system that reflects its transmission quality and service availability.

a network centric term outlining a way to prioritize IP packets based on the importance of the application when traversing over a network. Network administrators can tag a Type of Service bit in IP packet headers which network elements will then honor to, say, prioritize voice traffic over other application traffic in the event of congestion.

QoS guarantees network resources required by an application by means of providing a guaranteed bandwidth. Key requirement for videoconferences and Voice over IP (VoIP).

Enforcing a network policy that will impact bandwidth, delay (jitter), or traffic reliability.

A given Quality of Service level is sometimes required for a given user being tunneled between an LNS-LAC pair. For this scenario, a unique L2TP tunnel is created (generally on top of a new SVC) and encapsulated directly on top of the media providing the indicated QOS.

Quality of Service (QoS) means that an ATM provider guarantees to its customers that the amount of time it takes a packet to travel from source to destination will not exceed a specified level.

A measure of performance for a transmission system that reflects the quality and availability of service.

When used in the context of data communications, QoS refers a guarantee of a a certain level of service for a particular type of traffic, most often voice or video. These types of traffic are very sensitive to delayed or lost information.

Providing a guarantee of bandwidth in the network for use by applications.

A measure of a service's non-functional characteristics such as availability, performance, reliability, security, and integrity. It is used to match the needs of a service requestor with those of the service provider.

Term used to describe response time of a website or service to user requests. This is effected by Denial of Service attacks.

A term used in a Service Level Agreement (SLA) denoting a guaranteed level of performance (e.g., response times less than 1 second).

Quality of service is a measure of the ability to control and assign network bandwidth to specific traffic so as to provide predictable levels of IP-based data throughput based on the importance of the business process associated with that traffic.

A networking term that specifies a guaranteed throughput level. One of the biggest advantages of ATM over competing technologies such as frame relay and Fast Ethernet, is that it supports QoS levels. This allows ATM providers to guarantee to their customers that end-to-end latency will not exceed a specified level.

The ability to define a level of performance. QoS is enforced on all applications or scripts that run external to the Web browser (such as CGI and ASP scripts), but not on static HTML pages. The Default Plan is populated with the recommended QoS values; therefore, any site created using an unchanged Default Plan template is assigned this combination.

The ability of a network to provide improved service to selected network traffic over various underlying technologies including Ethernet and wireless LANs.

An effort to provide different prioritization levels for different types of traffic over a network. Various methods are used to achieve quality of service,...

A technology that counters the effects of congestion and queues in packet-switched networks. QoS divides the network traffic into different classes and processes those classes in different ways depending on the characteristics of the traffic e.g. by prioritising delay-sensitive traffic from Voice and Video applications.

Measurement of Royal Mailâ€(tm)s performance against the service targets set out in its licence.

Some switches support QoS (per 802.1p and 802.1Q standards) whereby tagged measures, or messages received on a certain port can be assigned one of eight levels of priority. QoS can be important where time-critical applications can be impaired by data delays. See a tutorial on Quality of Service (QoS)

A collective measure of the level of service delivered to the customer. QoS can be characterized by several basic performance criteria, including availability (low downtime), error performance, response time and throughput, lost calls or transmissions due to network congestion, connection set-up time, and speed of fault detection and correction. Service providers may guarantee a particular level of QoS (defined by a service level agreement or SLA) to their subscribers. QoS-enabled hardware and software solutions sort and classify IP packet requests into different traffic classes and allocates the proper resources to direct traffic based on various criteria including application type, user or application ID, source or destination IP address, time of day, and other user-specified variables.

QoS is the measure of the quality of service provided by a communications company.

An agreed or contracted level of service between a service customer and a Service Provider.

Quality of Service (QoS) - A set of quality assurance standards and mechanisms for data transmission.

Quality of Service is an obligation accepted and advertised by a provider entity to service consumers.

A guaranteed level of performance, often part of a service level agreement between a network service provider and end user.

A parameter specifying the level of performance needed for communications, such as transit delay, priority, accuracy, or reliability.

The concept of applying and ensuring specific, quantifiable performance levels on a shared network.

A networking feature that enables system administrators to control the performance properties of a network service, including throughput, transit delay, and priority. Real-Time Streaming Protocol (RTSP) A network protocol, defined in RFC 2326, for controlling one or more digital media streams or a presentation (the aggregate of related media streams).

In the fields of packet-switched networks and computer networking, the traffic engineering term Quality of Service (QoS) refers to control mechanisms that can provide different priority to different users or data flows, or guarantee a certain level of performance to a data flow in accordance with requests from the application program. Quality of Service guarantees are important if the network capacity is limited, especially for real-time streaming multimedia applications, for example voice over IP and IP-TV, since these often require fixed bit rate and may be delay sensitive.