Quality of Service use in Networking
Quality of service is a measure of service availability and transmission quality of a network or internetworks. Among the fundamentals of quality of service foundation, is the service availability. The network infrastructure must be available in plenty before successfully implementing quality of service. The transmission quality in the network is determined by loss, delay, and delay variation. Loss is a function of availability that shows the measure of packet numbers not received as compared to the sum of the number of packets transmitted. High-network availability leads to zero loss during non-congestion periods. During congestion, quality of service mechanisms determines the packets that are suitable to be selectively dropped in order to alleviate the congestion. While delay is the finite time a packet takes to reach the destination point after initial transmission from the send-point, delay variation is the difference in the end-to-end delay between packages.
In a network, human and technical factors affect the quality of service. Among the human factors are stability of service, user information, delays, and availability of service. Technical factors that affect quality of service include reliability, grade of service, effectiveness, scalability, and maintainability (Ranakrishman, 2008). Active and quality QoS management is important in networks as it is the key strategy for keeping networks in many companies responsive as well as productive. It also ensures that bandwidth is prioritized at the individual application level so that all the users receive the bandwidth they require in order to accomplish the business daily work. With QoS, an enterprise can monitor an organization’s needs from a central position by shaping and controlling traffic as it enters the central location, whether from the network or the internet- and balance between business-centered traffic and less important of personal traffic.
Each destination point in a Voice over Internet Protocol (VoIP) conversation uses a delay variation buffer in order to smoothen out the changes in the arrival time of voice data packets. The buffering in time might lead to overruns and under runs those results in an audible degradation of call quality. Quality of service makes it able to prioritize different applications, data-flows, or users. It also guarantees a level of performance to a data flow in network traffic. Quality of service is important, as people use it in the advanced technologies to allow computer networks to be of the same use as telephones networks i.e. for audio conversations, and supporting new applications that contain stricter service demands. It works to send prioritized information using the shortest time possible without losing any data. In digital networks, data loss leads to a loss in packets and disconnection.
A service is identified before it is provided to certain traffic. In addition to that, the packet may or may not be marked. These two tasks (identification and marking) make up classification. When someone identifies an unmarked packet, it is said that classification is on a per-hop basis. It happens with priority queuing and custom queuing. Flows are commonly identified by methods such as Access Control Lists, policy-based routing, Committed Access Rate, and Network Based Application Recognition.
It is very important to configure quality of service in the network because it provides a communication network, which is the backbone of any successful enterprise. These networks transport multiple and accurate data and hence should be measurable, predictable, and must guarantee services by managing bandwidth, jitter, delay, and loss parameters on an operational network. Quality of service offers preference to applications from network devices, in a way, that the quality of the data is not degraded to the point of becoming useless. Enterprises use quality of service tools to protect desirable traffic and providing differential service to the unwanted traffic e.g. propagation of worms.
An example of quality of service in use over a network is its’ application in streaming media. It refers to using quality of service to transmit multimedia to an end-user while at the same time the provider receives the feedback. A client can play the data e.g. recorded videos before transmitting the whole file. It is important to distinguish the delivery method from the media distributed applies especially to telecommunications network, as other delivery systems inherently stream e.g. radio or inherently non-stream e.g. video cassettes, and audio Cds. An example of an available and current streaming media is- internet television. It does not only have to be video applications as streaming text include audio voice such as live close captioning, and real-time text. Among the most applied use of the streaming concept are long video lectures, performed ‘online’ on the internet. A notable advantage of the presentation is the size of the presentation as they are occasionally very long, although people can interrupt or repeat arbitrary places.
Advancing in the computer networking field and powerful operating systems has made streaming media so practical and affordable for anyone. Today, the media streaming is done live or on demand. Live streaming involves sending the data to the recipient device without having to save it to the hard disk. On demand streams are saved on disks or file for an extended time while the only time for a live stream is strictly at one time e.g. during a football game (Grant and Meadows, 2009). People are increasingly using streaming media for social business and e-learning (Scott, 2013).
Among the situations when use of quality of service is helpful is its’ use at the Oracle database management. Many commercial enterprises consolidate and standardize their data center computer systems. They run many applications on clustered databases instead of using the individual servers for each application. Migration of applications into the internet brings up another problem of an open-workload management. The problem causes applications to fail, which is caused by demand surges.
An oracle database QoS management (Quality of service management) is an automated, policy-based product that ‘supervises’ the workloads requests in the whole system. It manages the resources shared by applications and configures the system so that the applications keep running at the needed performance level by the business. Oracle database QoS monitors the performance of every work request on the target system. By accurately measuring the time to complete a task and the response time, oracle database QoS management quickly detects bottlenecks in the system.In a situation whereby there are no sufficient resources to meet the demand, the systems attempt to satisfy more critical business performance requirements at the expense of the less critical performance requirements. The Oracle Database Quality of Service Management helps resolve problems quickly when the response time of the applications is within acceptable levels. Oracle database QoS management reduces the time and expertise requirements for system personnel that manage Oracle Real Application Clusters resources as well as helping reducing the performance outages. In addition, it helps manage the resources shared by an application in a cluster and enables identification and resolving of performance bottlenecks. These systems do not seek to make applications faster, but rather to remove the obstacle preventing the application from running at their set performance levels.
Yuksel, M, :Ramakrishman, K: Kalyamaraman. (2008). “Value of supporting class of service in IP Backbones” (pdf). IEE International Workshop on Quality of Service. Evanston, IL, USA. P.109-113.
Grant and Meadows. (2009). Communication Technology Update and Fundamentals 11th Edition p. 115
Kellner, S, (2013). “The Immediate Future of Webcasting ”. INXPO. Retrieved 29/July/2014.