Service Activation Testhead (SAT)
Introduction
SAT is a point-to-point out-of-service test methodology defined in the ITU-T Y.1564 standard. It is used to validate Ethernet-based service configuration and performance before the service is delivered to a customer. The test ensures that the network can support the service in accordance with the agreed-upon service level agreements (SLAs).
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Service configuration tests: These are short-duration tests that verify the accuracy of service configuration. They include:
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committed information rate (CIR)
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CIR combined with peak information rate (CIR-PIR)
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policing (traffic is tested at 125% of the configured PIR)
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Service performance test: This typically long-duration test evaluates key performance metrics of the service.
- throughput
- frame loss ratio (FLR)
- frame delay (FD), minimum, maximum, and average
- frame delay variation (FDV), minimum, maximum, and average
SAT architecture
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Ethernet loopback messages (ETH-LBM) - Throughput streams are encapsulated in ETH-LBM.
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Ethernet delay measurement messages (ETH-DMM) - Delay measurements are gathered using ETH-DMM.
SAT considerations
When testing between the Layer 2 subinterfaces within a MAC-VRF, traffic other than SAT traffic cannot be sent to or from the subinterfaces under test. Furthermore, the combined traffic exchanged between the subinterfaces in the MAC-VRF and the test streams must not exceed the overall capability of the network instance, or the network bandwidth. When traffic is generated from an up MEP in a MAC-VRF, the MAC address of the peer must be learned on the correct egress subinterface before starting the test. Broadcast, unknown, and multicast (BUM) traffic is likely to invalidate test results because of its distribution to all points in network instance.
The SAT tool is not intended to be used during active network events. Running a service activation test during such events can worsen ongoing events.
These are Layer 2 test functions. If the parent interface is a Layer 3 subinterface, as is the case with network instance default and IP-VRF, the state of the IP interface does not impact the test.
The SAT OAM tool does not verify the operational state of the service or subinterface before starting a test. You need to ensure that both the service and the subinterface are up before initiating the test. If either is down, the SAT tool reports a failure.
Changes to the service test configuration can only be made when the testhead tool is administratively disabled. You cannot change the administrative state if an associated service test is currently running. The service test must have completed or need to be stopped before any configuration changes are allowed.
These tests are point-to-point between a pair of MEPs. Only unicast traffic flows should be tested with the testhead OAM tool.
All test statistics are stored in volatile YANG state memory and the data must be collected immediately after the test completes.
The testhead tool operates using the Layer 2 rate, which excludes Layer 1 overhead. This overhead includes inter-frame gap (IFG) and preamble. Together, they add approximately 20 bytes (IFG is 12 bytes and preamble is 8 bytes) to each Ethernet frame. It is important to consider the percentage overhead based on the selected frame size used by the stream.
Disruptive fault conditions such as a MEP going down, a subinterface failure, or a hardware or card reboot, may stop a running test.
Deleting the service-test configuration, the oam service-activation-testhead container, or the oam container will delete all associated service-test statistics. A rollback has the same effect and will delete all associated statistics. Rollback will restore only the configuration and not the service-tests or their statistics. Test run numbers will be reinitialized to one.
SAT launch point
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Each subinterface reference must be unique across all test streams within a service test. The MEP references must also be unique per stream.
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Within a single service test, all streams must use the same subinterface type; either Layer 2 or Layer 3 subinterfaces. Mixing Layer 2 and Layer 3 subinterfaces within the same test is not allowed.
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Subinterfaces configured over Link Aggregation Groups (LAGs) are not supported.
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The subinterfaces can be:
- untagged
- single-tagged
- double-tagged
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When a test is launched from an Up MEP on a multi-complex system such as, the 7250 IXR-6e,7250 IXR-10e, or 7250 IXR-X3b, the same complex must be used for both ingress and egress. If ingress and egress are on different complexes, the delay measurements are not accurate.
The following table describes the supported combinations of network instance types, MEPs, and subinterfaces required to perform the test.
| Network instance type | Up MEP | Down MEP |
|---|---|---|
| MAC VRF | Layer 2 subinterface | Layer 2 subinterface |
| default | N/A | Layer 3 subinterface |
| IP VRF | N/A | Layer 3 subinterface |
SAT configuration
Acceptance criteria template
The acceptance criteria template is used to configure the thresholds that indicate the acceptable range for the service performance metrics. At the end of the test, the measured values for FD, FDV, and FLR are compared against the configured thresholds to determine the pass or fail criteria and to generate a trap to the management station.
- CIR threshold
- PIR threshold
- Delay threshold
- Delay variation threshold
- Loss threshold
- Loss threshold policing
- m-factor
Frame size template
The service testhead tool can be configured to generate a flow containing a frame sequence of different sizes. The testhead tool generates packet sizes as specified in the frame size template. The template is used to specify a mix of frames with different sizes that the tool can generate and choose from. The following table lists the frame size defaults for the default template. The default frame size template cannot be modified, and is viewable only using the info from state oam service-activation-testhead frame-size-template default command.
| a | b | c | d | e | f | g | h | u |
|---|---|---|---|---|---|---|---|---|
| 64 | 128 | 256 | 512 | 1024 | 1280 | 1518 | 9212 | 2000 |
- for single tagged subinterface, the throughput calculation must include an additional 4 bytes
- for double tagged subinterface, the throughput calculation must include an additional 8 bytes
Service test
The service-test is the main test container that includes all
the test elements. Every element must pass for the overall service test to complete
with an operational state of pass.
Up to eight service tests can be active at any time on each line card complex.
For Layer 2 network instances, multiple streams are allowed. Each test stream must have a unique source MEP over different Layer 2 subinterfaces. For Layer 3 subinterface, only one test stream is supported .
The stream run types are sequential and parallel. Sequential, processes all streams of the same type one after another before moving on to the next type. Parallel, runs all streams of the same type simultaneously. Performance tests always run concurrently regardless of the stream run type.
You can configure the test durations for CIR, CIR-PIR, policing, and performance types for up to 24 hours, 59 minutes, and 59 seconds. Performance metrics are measured after the test reaches the target rate. You can check the status and progress of the test at any time. Minor discrepancies in start and stop timing may occur, affecting throughput calculations. For long-duration tests, this impact is typically negligible.
Service stream
Up to eight service streams can be active at any time on each line card complex. Each stream is associated with an acceptance criteria template that contains thresholds to indicate the acceptable range for the service performance metrics. Each stream is associated with a frame size template that contains the Ethernet frame size ranges from 64 bytes to 9212 bytes, and the designated letters that are used to specify the frame size. The frame size for the specific service stream is configured using the sequence command in the frame-mix context in a service stream. The frame mix only allows the configuration of a single fixed frame size sequence. The configured size applies to all frames in the test flow.
You must configure a source MEP, which is associated with a subinterface and network instance under the test, and a destination MEP MAC address for the ETH-CFM LBM frame payload configuration. The data pattern for the payload, dot1p, and discard eligibility indicator (DEI) for the VLAN tags can also be specified. You cannot configure the VLAN tag; it is derived from the subinterface hosting the MEP. The MEP reference must be unique across all streams. The test fails to start if the MEP is not administratively enabled.
The testhead OAM tool generates traffic up to the specified rate and measures service performance metrics such as delay, delay variation, and loss.
Test start
Use the tools oam service-activation-testhead start command to start the test.
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At least one service stream must be enabled to start a service test.
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At least one test-type must be configured to administratively enable the service stream.
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At least one test-duration must meet the minimum test duration to administratively enable the service test and service stream. Every test has a minimum test duration of 30 seconds.
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The service test must be admin enabled before issuing the start command.
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The associated interface must be operationally up.
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The MEP must be admin enabled.
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A unicast destination MAC address must be configured.
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The total number of stored service test records must be less than 500.
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The bandwidth required for the test is not available on the line card.
Configure acceptance criteria template
To configure acceptance criteria template, use the oam service-activation-testhead acceptance-criteria-template command. Provide a name for the template and configure the parameters shown in the example.
Acceptance criteria template configuration
--{ + candidate shared default }--[ ]--
# info with-context oam service-activation-testhead acceptance-criteria-template test-1
oam {
service-activation-testhead {
acceptance-criteria-template test-1 {
description None
cir-threshold 10000000
pir-threshold 1000000
loss-threshold 0.0500
loss-threshold-policing 25.0000
delay-threshold 100
delay-var-threshold 20
m-factor 1000
}
}
}Configure frame size template
Use the oam service-activation-testhead frame-size-template command and provide a name for the template. Configure the parameters shown in the example.
Frame size template configuration
--{ + candidate shared default }--[ ]--
# info with-context oam service-activation-testhead frame-size-template test-1
oam {
service-activation-testhead {
frame-size-template test-1 {
size-a 64
size-b 128
size-c 256
size-d 512
size-e 1024
size-f 1280
size-g 1518
size-h 9212
size-u 2000
}
}
}
Configure SAT and display results
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the MEP is admin enabled.
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the interface is operationally up.
Perform the following steps to configure the SAT service tests and service streams:
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Execute the oam service-activation-testhead service-test
command to configure the service test. Configure the parameters as shown in the
example.
Configuring the service test parameters
--{ + candidate shared default }--[ ]-- # info with-context oam service-activation-testhead service-test SAT-1 oam { service-activation-testhead { service-test sampletest-1 { description None stream-run-type parallel test-duration { cir { minutes-seconds 05:00 } cir-pir { minutes-seconds 10:00 } policing { minutes-seconds 10:00 } performance { hours-minutes-seconds 00:15:00 } } } } } -
Execute the oam service-activation-testhead service-test
service-stream command to configure the service stream. Configure
the parameters as shown in the example.
Configuring the service stream parameters
--{ + candidate shared default }--[ ]-- # info with-context oam service-activation-testhead service-test sampletest-1 service-stream 1 oam { service-activation-testhead { service-test sampletest-1 { service-stream 1 { description None acceptance-criteria-template test-1 frame-mix { frame-size-template test-1 sequence e } test-types { cir true cir-pir true policing true performance true } frame-payload { ethernet { dst-mac 02:02:03:01:01:01 eth-cfm { source { domain-id 10 association-id 10 mep-id 1 } } } } } } } } -
Configure the administrative state of the service stream as enable and then
configure the administrative state of the service test as enable.
Administratively enabling the service stream and service test
--{ + candidate shared default }--[ ]-- # info with-context oam service-activation-testhead oam { service-activation-testhead { acceptance-criteria-template test-1 { description None cir-threshold 10000000 pir-threshold 1000000 loss-threshold 0.0500 loss-threshold-policing 25.0000 delay-threshold 100 delay-var-threshold 20 m-factor 1000 } frame-size-template test-1 { size-a 64 size-b 128 size-c 256 size-d 512 size-e 1024 size-f 1280 size-g 1518 size-h 9212 size-u 2000 } service-test sampletest-1 { admin-state enable description None stream-run-type parallel test-duration { cir { minutes-seconds 05:00 } cir-pir { minutes-seconds 10:00 } policing { minutes-seconds 10:00 } performance { hours-minutes-seconds 00:15:00 } } service-stream 1 { admin-state enable description None acceptance-criteria-template test-1 frame-mix { frame-size-template test-1 sequence e } test-types { cir true cir-pir true policing true performance true } frame-payload { ethernet { dst-mac 02:02:03:01:01:01 eth-cfm { source { domain-id 10 association-id 10 mep-id 1 } } } } } } } } -
Use the tools oam service-activation-testhead service-test
start command to start a service test.
Starting a service test
--{ + candidate shared default }--[ ]-- # tools oam service-activation-testhead service-test sampletest-1 start /oam/service-activation-testhead/service-test[test-name=sampletest-1]: Service test sampletest-1 is started with run index 3Note: The following guidelines for starting a service test apply:-
You cannot start two service tests with the same name. When the start command is issued, attempting to start a second service test with the same name fails the start command with an appropriate error.
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When a stop command is issued for a service test that is not running, an error message indicating the test is not running appears.
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Use the show oam service-activation-testhead
service-activation-tests command to display the run instance
summary of a service test.
Displaying the run instance summary
--{ + candidate shared default }--[ ]-- # show oam service-activation-testhead service-activation-tests +--------------+----------+------------------------------+ | test-name | test-run | completed | +==============+==========+==============================+ | sampletest-1 | 1 | 2025-07-04T21:44:00.0Z+05:30 | | sampletest-1 | 2 | 2025-07-04T21:44:00.0Z+05:30 | | sampletest-1 | 3 | 2025-07-04T21:44:00.0Z+05:30 | | sampletest-2 | 1 | 2025-07-04T21:44:00.0Z+05:30 | | sampletest-2 | 2 | 2025-07-04T21:44:00.0Z+05:30 | | sampletest-2 | 3 | 2025-07-04T21:44:00.0Z+05:30 | | sampletest-3 | 1 | 2025-07-04T21:44:00.0Z+05:30 | | sampletest-3 | 2 | 2025-07-04T21:44:00.0Z+05:30 | | sampletest-3 | 3 | 2025-07-04T21:44:00.0Z+05:30 | | test-1 | 1 | | +--------------+----------+------------------------------+ -
Use the show oam service-activation-testhead service-test
run command to display the service test results.
Displaying the service test results
--{ + candidate shared default }--[ ]-- # show oam service-activation-testhead service-test sampletest-1 run 1 -------------------------------------------------------------------------------- Y.1564 Results for run 1 Service Test sampletest-1 -------------------------------------------------------------------------------- Description : None Oper State : passed Start Time : 2025-07-04T16:47:07.123Z End Time : 2025-07-04T16:47:44.610Z Stream Run Type : parallel -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Y.1564 Results for Stream 1 Run 1 Service Test sampletest-1 -------------------------------------------------------------------------------- Description : None Oper State : passed Network Inst : default Source MEP : 52 MEP Domain : 10 MEP Assoc. : 10 Subinterface : ethernet-1/1.1 Source MAC : C0:14:B8:0D:8B:BA Dest MAC : 02:02:03:01:01:01 Pattern (Dec): 0 Pattern (Hex) : 0x0 C-Tag Dot1p : 7 C-Tag DEI : false S-Tag Dot1p : 7 S-Tag DEI : false Frm Size Tmpl: fst Frm Sequence : c Frame Size a : 64 Frame Size b : 150 Frame Size c : 256 Frame Size d : 512 Frame Size e : 1024 Frame Size f : 1600 Frame Size g : 1518 Frame Size h : 9212 Frame Size u : 2000 Acp Crit Tmpl: act Test Types : CIR-PIR -------------------------------------------------------------------------------- -------------------------------------------------------------------------------- Y.1564 Results for Stream 1 Run 1 Test Type cir-pir Service Test sampletest-1 -------------------------------------------------------------------------------- Oper State : passed Test Duration: 00:30 (mm:ss) Time Left : 0 s Start Time : 2025-07-04T16:47:09.489Z End Time : 2025-07-04T16:47:39.595Z Frms Injected: 2939470 Frms Received: 2939470 Min Delay : 15 us Min Delay Var: 0 us Max Delay : 17 us Max Delay Var: 2 us Avg Delay : 15 us Avg Delay Var: 0 us -------------------------------------------------------------------------------- ================================================================================ Test Compliance Report ================================================================================ Criteria Throughput(kbps) FLR (%) Delay (us) Delay Var (us) -------------------------------------------------------------------------------- Acceptable 200000 (Not Specified)(Not Specified)(Not Specified) Configured 200000 (Not Specified)(Not Specified)(Not Specified) M-Factor 2000 N/A N/A N/A Measured 199958 0.0000 15 0 Result pass pass pass pass ================================================================================