Operation Manual – QoSH3C S7500 Series Ethernet Switches Chapter 1 QoS Configuration1-8z CIRz CBSz Peak information rate (PIR)z Excess burst size (EBS)Two token buckets are used in this evaluation. The rates of putting tokens into the twobuckets are CIR and PIR respectively, and the sizes of two buckets are CBS and EBSrespectively (the two buckets are called C bucket and E bucket respectively for short),representing different permitted burst levels. In each evaluation, you can adopt differenttraffic control policies in different conditions, including “enough tokens in C bucket”,“insufficient tokens in C bucket but enough tokens in E bucket” and “insufficient tokensin both C bucket and E bucket”.II. TPA typical TP application is to supervise the specification of a traffic into the network andlimit the specification within a reasonable range, or to punish the extra traffic. Therefore,the network resources and the interests of the operators are protected. For example,you can limit HTTP packets within 50% of the network bandwidth. If the traffic of acertain connection is excess, TP can choose to drop the packets or to reset the priorityof the packets.TP is widely used for policing the traffic into the network of internet service providers(ISP).TP can classify the policed traffic and perform pre-defined policing actionsaccording to different evaluation results. These actions include:z Forward: Forward the packet whose evaluation result is “conforming” or markDSCP precedence for packets in the Diff-Serv network and then forward them.z Drop: Drop the packet whose evaluation result is “nonconforming”.z Remark the precedence and then forward: Remark the priority of the packetwhose evaluation result is “partly-conforming” and then forward it.z Perform the next-level policing: TP can be performed level by level and in eachlevel more detailed objects are policed.1.1.9 RedirectYou can re-specify the forwarding port of a packet as required by your own QoS policy.1.1.10 Queue SchedulingWhen congestion occurs in the network, the problem that many packets compete forresources must be solved, usually in the way of queue scheduling.In the following section, strict priority (SP) queues and weighted round robin (WRR)queues are introduced.1) SP queue
