1. Xianfeng Zeng Sept 13 1999 Characteristics of ATM Uses small, fixed-sized cells Connection-oriented Supports multiple service types Applicable to LAN and WAN Cells Voice Data Video

2. Xianfeng Zeng Sept 13 1999 Contract ATM Service Criteria Contract Traffic Descriptors Peak cell rate Sustainable cell rate Maximum burst size Minimum Cell Rate Quality of Service Delay Cell loss ATM Network

3. QoSTraffic Descriptor Application ATM Service Categories Constant Bit Rate (CBR) Real Time Voice and Video LOWHIGH Tolerance Cell Delay Cell Loss PCR Peak Cell Rate

4. ATM Service Categories Variable Bit Rate (VBR-RT/VBR-NRT) QoSTraffic Descriptor LOWHIGH Tolerance Cell Delay (NRT) Cell Delay (RT) PCR SCR Peak Cell Rate Sustainable Cell Rate MBS Maximum Burst Size Cell Loss Packetized Voice/Video, SNA Application

5. QoSTraffic Descriptor ATM Service Categories Unspecified Bit Rate (UBR) Application Data Transfer LOWHIGH No Guarantees Send and Pray Tolerance Cell Loss Cell Delay

6. ATM Service Categories Available Bit Rate (ABR) Also uses Congestion Feedback Mechanisms QoS LOW HIGH Traffic Descriptor PCR MCR Peak Cell Rate Minimum Cell Rate Tolerance Cell LossCell Delay LAN Interconnect for Data Application

7. Xianfeng Zeng Sept 13 1999 Contract Traffic Control Techniques Contract Traffic Parameters Peak cell rate Sustainable cell rate Burst tolerance Etc. Quality of Service Delay Cell loss ATM Network Connection Management

8. ATM Network Traffic Control Techniques You are Not in Conformance with the Contract. What Should the Penalty Be?? PASS MARK CLP BIT DROP ?DECISION? Usage Parameter Control (UPC) aka Policing Traffic Management REBEL APPLICATION Contract

9. Traffic Control Techniques EFCI Marking—Explicit Forward Congestion Indicator Congestion flag set on forward cells only Destination end-system sends RM cells back to source Source Destination Forward RM Backward EFCI Set XX XX Congestion Experienced Slow Down ABR Congestion Feedback

10. Xianfeng Zeng Sept 13 1999 Traffic Control Techniques Source Destination Forward RM Backward Congestion Experienced Slow Down ABR Congestion Feedback RM Congestion Experienced Slow Down X Amount Explicit rate marking Switches can tell source at exactly what rate to transmit

11. ATM Transport Standards “Root”“Leaves” UNI 3.X Connection Types Point-to-point Uni-directional or bi-directional traffic Point-to-multipoint Uni-directional (root-to-leaves) only Only Root can add leaves