Information About Service Performance Operations
Y.1564 is an Ethernet service activation test methodology and is the standard for turning up, installing, and troubleshooting Ethernet and IP based services. Y.1564 is the only standard test methodology that allows a complete validation of Ethernet service-level agreements (SLAs) in a single test.
Service activation testing (SAT) is designed to measure the ability of a Device Under Test (DUT) or a network under test to properly forward traffic in different states.
Effective with Cisco IOS XE Everest Release 16.5.1, 10 Gigabit (10G) SAT session is supported on Cisco RSP2 and Cisco RSP3 Modules. Any SAT session with a rate-step greater than or equal to 1 Gbps is considered as 10G SAT session.
Cisco implementation of ITU-T Y.1564 has three key objectives:
-
To serve as a network SLA validation tool, ensuring that a service meets its guaranteed performance settings in a controlled test time.
-
To ensure that all services carried by the network meet their SLA objectives at their maximum committed rate, thus proving that under maximum load, network devices and paths can support all traffic as designed.
-
To perform medium-term and long-term service testing, confirming that network elements can properly carry all services while under stress during a soaking period.
The following Key Performance Indicators (KPI) metrics are collected to ensure that the configured SLAs are met for the service or stream. These are service acceptance criteria metrics.
-
Information Rate (IR) or throughput—Measures the maximum rate at which none of the offered frames are dropped by the device under test (DUT). This measurement translates into the available bandwidth of the Ethernet virtual connection (EVC).
-
Frame Transfer Delay (FTD) or latency—Measures the round-trip time (RTT) taken by a test frame to travel through a network device, or across the network and back to the test port.
-
Frame Loss Ratio (FLR)—Measures the number of packets lost from the total number of packets sent. Frame loss can be due to a number of issues such as network congestion or errors during transmissions.
-
Frame Delay Variation (FDV) or jitter—Measures the variations in the time delays between packet deliveries.
The below table presents the KPI support matrix for RSP3 Module:
KPI |
ASIC-Based SADT |
FPGA-Based SADT |
||
---|---|---|---|---|
Internal Direction |
External Direction |
Internal Direction |
External Direction |
|
Delay |
N |
N |
Y |
Y |
Jitter |
N |
N |
Y |
Y |
Loss |
Y |
Y |
Y |
Y |
Throughput |
Y |
Y |
Y |
Y |
![]() Note |
We always recommend that you use FPGA-based SADT. SADT Internal sessions do not support ASIC-based SAT. |
Because they interconnect segments, forwarding devices (switches and routers) and network interface units are the basis of any network. If 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. Service performance testing is designed to measure the ability of DUT or network under test, to correctly forward traffic in different states. The Cisco implementation of ITU-T Y.1564 includes the following service performance tests:
-
Minimum data rate to CIR—Bandwidth is generated from the minimum data rate to the committed information rate (CIR) for the test stream. KPI for Y.1564 are then measured to ensure that the configured service acceptance criteria (SAC) are met.
-
CIR to EIR—Bandwidth is ramped up from the CIR to the excess information rate (EIR) for the test stream. Because EIR is not guaranteed, only the transfer rate is measured to ensure that CIR is the minimum bandwidth up to the maximum EIR. Other KPI is not measured.
Service performance supports four operational modes: two-way statistics collection, one-way statistics collection, passive measurement mode, and traffic generator mode. Statistics are calculated, collected, and reported to the IP SLAs module. The statistics database stores historical statistics pertaining to the operations that have been executed.
-
One-way statistics collection—Both the passive measurement mode and the traffic generator mode are used in conjunction with each other. One device sends traffic as the generator and another device receives traffic in the passive mode and records the statistics. The passive mode is distinct from the two-way mode, where the remote device records statistics instead of looping back the traffic and the sending device records only the transmit statistics.
-
Two-way statistics collection—All the measurements are collected by the sender. The remote target must be in the loopback mode for the two-way statistics to work. Loopback mode enables the traffic from the sender to reach the target and be returned to the sender.
-
Passive measurement mode—This mode is enabled by excluding a configured traffic profile. A passive measurement operation does not generate live traffic. The operation collects only statistics for the target configured for the operation.
-
Traffic generator mode—This mode records transmit statistics for the number of packets and bytes sent.