Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Unit 3 Traffic Policing and Shaping 2616009:Network Traffic Engineering 3:Traffic Policing and Shaping Page.1
2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 3: Traffic Policing and Shaping Page.1 Unit 3 Traffic Policing and Shaping
Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Roadmap Traffic Shaping and Policing -What and why is traffic shaping and traffic policing Leaky Bucket Token Bucket Traffic -Generic Cell Rate Algorithm (GCRA) -Virtual scheduling algorithm implementati Leaky bucket algorithm implementation 2616009:Network Traffic Engineering 3:Traffic Policing and Shaping Page.2
2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 3: Traffic Policing and Shaping Page.2 Roadmap • Traffic Shaping and Policing What and why is traffic shaping and traffic policing Leaky Bucket Token Bucket Traffic Generic Cell Rate Algorithm (GCRA) -Virtual scheduling algorithm implementati - Leaky bucket algorithm implementation
Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Traffic Policing Question: A connection accepted by CAC,it's QoS can be satisfied,if the source obeys the traffic descriptor.What happens if the traffic flow violates the initial contract? Answer: The network may not maintain acceptable performance What can be done? Traffic Policing is performed by the network to ensure that the parameter specified by the user are being complied. Traffic Policing The process of monitoring and enforcing the traffic flow What Traffic Policing do? Discard the nonconforming traffic S Tag the nonconforming traffic with lower priority) 2616009:Network Traffic Engineering 3:Traffic Policing and Shaping Page.3
2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 3: Traffic Policing and Shaping Page.3 Traffic Policing • Question: A connection accepted by CAC, it’s QoS can be satisfied, if the source obeys the traffic descriptor. What happens if the traffic flow violates the initial contract? • Answer: The network may not maintain acceptable performance • What can be done? Traffic Policing is performed by the network to ensure that the parameter specified by the user are being complied. • Traffic Policing The process of monitoring and enforcing the traffic flow • What Traffic Policing do? §Discard the nonconforming traffic §Tag the nonconforming traffic ( with lower priority)
Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Leaky Bucket Faucet packet unregulated flow Leaky bucket Host Compute (Overflow = Non-Conforming Traffic) The bucket holds packets Water Water drips out at a Interface containing a constant rate 0 leaky bucket 0 0(Conforming Traffic） 回 0 Regulated flow 口 Network Provides traffic shaping:Input bursty.Output rate controlled. Provides traffic policing:Ensure that users are sending traffic within specified limits Excess traffic discarded or admitted with CLP=1 2616009:Network Traffic Engineering 3:Traffic Policing and Shaping Page.4
2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 3: Traffic Policing and Shaping Page.4 Leaky Bucket Faucet Leaky bucket Water drips out at a constant rate (Overflow => Non-Conforming Traffic) ( Conforming Traffic ) Water unregulated flow Host Computer Network packet The bucket holds packets Regulated flow Interface containing a leaky bucket • Provides traffic shaping: Input bursty. Output rate controlled. • Provides traffic policing: Ensure that users are sending traffic within specified limits Excess traffic discarded or admitted with CLP = 1
Feng Gang National Laboratory of Communication,UESTC Aug 2017 Ver 1.4 Simple Leaky Bucket Shaper B β： Buffer size (Queue Length) p:Channel capacity (Leakage rate) Cumulative Traffic Arrival curve slope=p Departure curve time 2616009:Network Traffic Engineering 3:Traffic Policing and Shaping Page.5
2616009: Network Traffic Engineering Feng Gang National Laboratory of Communication, UESTC Aug 2017 Ver 1.4 3: Traffic Policing and Shaping Page.5 Simple Leaky Bucket Shaper b Cumulative Traffic slope= time Arrival curve Departure curve b: : Buffer size (Queue Length) Channel capacity (Leakage rate)