Introducing Traffic Policing and Shaping参考.ppt

Implement the DiffServ QoS Model Introducing Traffic Policing and Shaping Traffic Policing and Shaping Overview Why Use Policing? To limit access to resources when high-speed access is used but not desired (subrate access)当不期望的对某个资源高速访问时去限制访问速率（子速率接入） To limit the traffic rate of certain applications or traffic classes对确定的应用或流量类别进行速率限制 To mark down (recolor) exceeding traffic at Layer 2 or Layer 3在第二层或第三层重标记流量． Why Use Shaping? To prevent and manage congestion in ATM, Frame Relay, and Metro Ethernet networks, where asymmetric bandwidths are used along the traffic path用于阻止和管理流量路径中有不对称带宽的ATM,Frame Relay和Metro Ethernet网络拥塞. To regulate the sending traffic rate to match the subscribed (committed) rate in ATM, Frame Relay, or Metro Ethernet networks用于在ATM, Frame Relay或者Metro Ethernet网络中遵守订购的流量速率. To implement shaping at the network edge在网络边缘实现整形. Traffic Policing Example Do not rate-limit traffic from mission-critical server.对关键性服务器产生流量不执行速率限制. Rate-limit file-sharing application traffic to 56 kbps.将文件共享应用速率限制到56 kbps. Traffic Policing Example Do not rate-limit traffic from mission-critical server.对关键性服务器产生流量不执行速率限制. Rate-limit file-sharing application traffic to 56 kbps.将文件共享应用速率限制到56 kbps. Traffic Policing and Shaping Example Traffic Policing and Shaping Example Central to remote site speed mismatch中心站点与远程站点速度不匹配 Traffic Policing and Shaping Example Central to remote site speed mismatch中心站点与远程站点速度不匹配 Remote to central site oversubscription远程站点到中心站点oversubscription Traffic Policing and Shaping Example Central to remote site speed mismatch中心站点与远程站点速度不匹配 Remote to central site oversubscription远程站点到中心站点oversubscription Both situations result in buffering and in delayed or dropped packets. Policing vs. Shaping Single Token Bucket Single Token Bucket (Cont.) Single Token Bucket (Cont.) Single Token Bucket (Cont.) Single Token Bucket Class-Based Policing Cisco IOS Traffic Policing Mechanism Cisco IOS Traffic-Shaping Mechanisms Applying Rate Limiting Summary Tr