ccna pdf file

ccna pdf file.Scalable, with scalability limited only by network bandwidth.No special QoS deployment is required, making it the simplest QoS model.The disadvantages of this model are described below.There are no transmission guarantees.No packets are prioritized, and voice, video, and business-critical data are treated the same as normal data.2. Integrated Services (IntServ) ModelThe IntServ model uses resource reservation and admission control mechanisms to establish and maintain QoS, also known as "hard QoS". o Hard QoS guarantees end-to-end traffic characteristics (such as bandwidth, latency, and packet loss) and ensures that critical applications receive predictable and guaranteed service levels. In this model, before data is sent, the application requests a specific type of service from the network. The application informs the network of its traffic profile and requests specific types of services, including its requirements for bandwidth and latency. The IntServ model uses Resource Reservation Protocol ( RSVP) to issue QoS demand signaling for application traffic in the device, and the originating application can begin transmission if the network device in the path can reserve the necessary bandwidth. If the requested reservation in the path fails, the originating application does not send any data. The edge router performs admission control based on information from the application and available network resources. RSVP comes before the application starts sending data to request network resources for that application, so it is out-of-band signaling. Integration services require that network resources on all connection paths be pre-reserved for individual data flows, and with the large number of application flows currently on the Internet backbone, it becomes inconceivable for guaranteed services to provide QoS services for each flow. Therefore, this model is difficult to apply to large-scale networks on its own and is currently used mainly in conjunction with MPLS TrafficEngineering (TE).Explicitly implement end-to-end resource access control.Dynamic port signaling pre-request policy is used to implement admission control. The drawbacks of this model are described below.Continuous signaling can be resource intensive.