a service is not correctly configured on any one of these devices within the end-to-end path, network performance can be greatly affected, leading to potential service outages and network-wide issues such as congestion and link failures. The Service configuration test is designed to measure the ability of DUT or network under test to properly forward in different states: In the CIR phase, where performance metrics for the service are measured and compared to the SLA performance objectives. In the EIR phase, where performance is not guaranteed and the services transfer rate is measured to ensure that CIR is the minimum bandwidth. In the discard phase, where the service is generated at the overshoot rate and the expected forwarded rate is not greater than the committed information rate or excess rate (when configured). In the CBS (Committed Burst Size) phase, performance metrics are measured while changing traffic from the CIR to the line rate. In the EBS (Excess Burst Size) phase, performance metrics are measured while changing traffic from the EIR to the line rate. Service performance test As network devices come under load, they must prioritize one traffic flow over another to meet the KPIs set for each traffic class. With only one traffic class, there is no prioritization performed by the network devices since there is only one set of KPIs. As the number of traffic flows increase, prioritization is necessary and performance failures may occur. The service performance test measures the ability of the DUT or network under test to forward multiple services while maintaining SLA conformance for each service. Services are generated at the CIR, where performance is guaranteed, and pass/fail assessment is performed on the KPI values for each service according to its SLA. Service performance assessment must also be maintained for a medium- to long-term period as performance degradation will likely occur as the network is under stress for longer period of times. The service performance test is designed to soak the network under full committed load for all services and measure performance over medium and long test time. The time frame to complete this section of the test is recommended to follow ITU-T M.2110 which mentions intervals of 15min, 2hour or 24hour allowing network availability to be determined. Metrics The Y.1564 focuses on the following KPIs for service quality: Bandwidth or Information rate (IR): This is a bit rate measure of available or consumed