Configuring Frame Relay QoS 1721Configuring Frame Relay interface queuingThe user can configure these queuing types on a Frame Relay interface: FIFO, PQ,CQ, WFQ, CBQ and RTPQ. All of them are the queues owned by a general QoS.For configurations of these queues, refer to “Congestion Management” on page1649 for details.Frame Relay interface also supports PVC interface priority queuing (PVC PQ). Thisqueuing type can only be applied on a Frame Relay interface. After Frame Relaytraffic shaping or Frame Relay congestion management is enabled on a FrameRelay interface, the queuing type on the interface can only be either FIFO or PVCPQ.A PVC PQ has four sub-queues. They are respectively high-priority queue (top),medium-priority queue (middle), normal-priority queue (normal) and low-priorityqueue (bottom). The priorities are listed in descending order. The packets will betransmitted according to the priority sequence. Specifically, all the packets in thetop queue will be first transmitted, then the packets in the middle queuefollowed by the packets in the normal queue, and finally those in the bottomqueue. Each Frame Relay PVC on the interface has its own PVC PQ priority.Therefore, the packets from this PVC can only enter the corresponding PVC PQ.Follow these steps to configure PVC PQ:Configuring Frame RelayFragmentationThe system supports end-to-end fragmentation of FRF. 12 developed by FrameRelay Forum.On low-speed frame relay lines, big data packets may cause increase intransportation delay. Frame relay fragmentation feature can divide a big framerelay packet into several small ones so as to ensure data on low-speed lines canalso be sent with low delay.When voice and data are sent simultaneously, the sending of big data packets willbe holding bandwidth for a long period of time, which will accordingly lead todelay or even discard of a voice packet and will influence voice quality. The aim forconfiguring frame relay fragmentation is to reduce voice delay and ensure thereal-time of voice. After fragmentation is configured, big data packet will bedivided into smaller data fragments, and voice packets will be sent with theTo do... Use the command... RemarksEnter system view system-view -Enter Frame Relay interfaceviewinterface interface-typeinterface-number-Set the queuing type of FrameRelay interface to PVC PQ andset the length of each PVC PQat the same timefr pvc-pq [ top-limitmiddle-limit normal-limitbottom-limit ]*RequiredExit Frame Relay class view quit -Enter Frame Relay class view fr class class-name -Set the PQ priority of FrameRelay PVCpvc-pq { bottom | middle |normal | top }OptionalBy default, the packets sentby FR PVC enter into thenormal PVC PQ.
