Information About Service Performance Operations
Y.1564 is an Ethernet service activation test methodology. It 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 performance testing is designed to measure the ability of a Device Under Test (DUT) or a network under test to forward traffic in different states.
Effective with Cisco IOS XE Everest Release 16.5.1, 10 Gigabit (10G) SAT External session is supported. Any SAT session with a rate-step greater than or equal to 1 Gbps is considered as 10G SAT session.
Effective with Cisco IOS XE Everest Release 16.12.1, 10 Gigabit (10G) SAT Internal session is supported. 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:
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To serve as a network SLA validation tool, ensuring that a service meets its guaranteed performance settings in a controlled test time.
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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.
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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 indicate the configured SLAs for the service or stream. These following service acceptance criteria metrics are:
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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).
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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.
Note
If the delay is more than 4.2 sec, then the software is not capable of capturing it in SADT statistics.
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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.
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Frame Delay Variation (FDV) or jitter—Measures the variations in the time delays between packet deliveries.
KPI |
FPGA- Based SADT |
|
---|---|---|
Internal Direction |
External Direction |
|
Delay |
Y |
Y |
Jitter |
Y |
Y |
Loss |
Y |
Y |
Throughput |
Y |
Y |
Because they interconnect segments, forwarding devices (switches and routers) and network interface units are the basis of any network. Incorrect configuration of a service on any of these devices within the end-to-end path, can affect the network performance. This could also lead 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 forward traffic in different states. The Cisco implementation of ITU-T Y.1564 includes the following service performance tests:
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Minimum data rate to CIR—Generates bandwidth from the minimum data rate to the committed information rate (CIR) for the test stream. Measures KPI for Y.1564 to meet configured service acceptance criteria (SAC).
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CIR to EIR—Ramps up bandwidth from the CIR to the excess information rate (EIR) for the test stream. Measures the transfer rate to ensure that CIR meets the minimum bandwidth of the maximum EIR. Other KPI is not measured.
Note
In SADT configuration, if the rate of EIR is greater than CIR + EIR, then above EIR is not measured. The stats for Above EIR remains 0 in following command: show ip sla statistics
Service performance supports four operational modes:
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Two-way statistics collection
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One-way statistics collection
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Passive measurement mode
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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 are executed.
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One-way statistics collection—Both the passive measurement mode and the traffic generator mode are used along 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 the statistics instead of looping back the traffic. The sending device records only the transmit statistics.
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Two-way statistics collection—The sender collects all the measurements. 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 sent back to the sender.
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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.
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Traffic generator mode—This mode records statistics for the number of packets and bytes transmitted.
Prerequisites for IP SLA - Service Performance Testing
Ensure that the direction configured for the measurement-type direction {internal | external} and the profile traffic direction {internal | external} commands is the same.