FTAS 4.0: 170 New Test Cases for Scale, Resiliency and Day-2 Operations
October 1, 2026
Fabric Test Automation Suite
FTAS 4.0 is here, adding 170 new test cases and bringing the total suite to 646. This release is shaped directly by the networks our customers run in production. It expands automation for high-density port breakout, scales BGP, ARP, and VXLAN validation to new limits, and introduces new scenario coverage built with our customers.
The goal is simple: every scenario we automate is one less failure mode that reaches a live fabric. FTAS 4.0 pushes that coverage further into scale, resiliency, and day-2 operations, where the most elusive network issues hide.
FTAS 4.0 by the numbers
| Test suite | Total test cases (4.0) | New in 4.0 |
|---|---|---|
| SONiC CLI | 512 | +64 |
| FMCLI | 134 | +106 |
| Total | 646 | +170 |
Highlight: FMCLI saw the largest expansion in this release, growing nearly fivefold from 28 to 134 test cases.
Key highlights in FTAS 4.0
Dynamic port breakout across every speed
Port breakout is one of the most common reconfiguration tasks in modern data centers, and one of the easiest to get wrong. FTAS 4.0 automates dynamic port breakout scenarios across 800G, 400G, 200G, and 100G configurations, so teams can validate breakout changes consistently before touching production.
Major FMCLI automation expansion
FMCLI gets the largest single boost in this release. We added 106 new test cases covering core operational and management workflows, taking FMCLI coverage from 28 to 134 test cases.
BGP and ARP under high stress
Routes that hold steady in a lab can behave unpredictably during link flaps. FTAS 4.0 introduces link flap, burst flap, and rapid flap validation at 32K, 64K, and 128K BGP scale, alongside 2K ARP entries. It also adds ECMP-based route scale scenarios up to 64K routes.
L3VNI and L2VNI scale validation
New L3VNI and L2VNI scale automation covers up to 4,094 VLANs. Tests validate ARP and FDB aging, forced clears and traffic recovery, and confirm the fabric stays resilient during spine or uplink failures.
ACL scale and live configuration updates
FTAS 4.0 adds ACL scale validation, alongside new automation for updating ACLs with the config update CLI. Key coverage includes:
- Table-scoped ACL updates and handling of malformed input
- Impact analysis of sequential ACL switchovers, including the IPv6/L3V6 table codepath
- Traffic permission verification during active switchovers
Broader telemetry and SNMPv3 coverage
SNMPv3 validation now spans interface, LLDP, entity, IP, VLAN, loopback and management VRF walks, giving monitoring teams greater confidence that switch telemetry is accurate.
RFC 2544 performance benchmarking
Extended RFC 2544 frame-size validation broadens FTAS performance benchmarking across a wider range of packet sizes.
Smarter VXLAN ARP handling
New targeted tests validate ARP flush and IP update behavior when a MAC address is reused in VXLAN deployments, helping catch hard-to-trace forwarding issues before they reach production.
Framework and tooling upgrades
Beyond new test cases, FTAS 4.0 improves the day-to-day experience for developers and operators.
Reliable diagnostics
Techsupport dumps are now collected automatically before test cleanup runs, so diagnostic data is captured reliably whenever a test fails.
Live run monitoring
Track test execution status in the UI as it happens, with no need to wait for the full run to finish.
Get started with FTAS 4.0
FTAS 4.0 is available today.
Frequently Asked Questions
What is FTAS 4.0?
FTAS 4.0 is the latest release of the Fabric Test Automation Suite, adding 170 new test cases and bringing the total suite to 646. It expands automation coverage for scale, resiliency, and day-2 operations based directly on production network scenarios from customers.
How many test cases does FTAS 4.0 include?
FTAS 4.0 includes 646 total test cases, with 512 covering SONiC CLI and 134 covering FMCLI. The 170 new cases added in this release represent the largest single expansion to date.
What area saw the biggest growth in FTAS 4.0?
FMCLI saw the largest expansion, growing from 28 to 134 test cases, nearly a fivefold increase. The 106 new FMCLI test cases cover core operational and management workflows.
What BGP and ARP scale levels does FTAS 4.0 validate?
FTAS 4.0 introduces link flap, burst flap, and rapid flap validation at 32K, 64K, and 128K BGP scale, alongside 2K ARP entries. It also adds ECMP-based route scale scenarios up to 64K routes.
Does FTAS 4.0 include VXLAN testing?
Yes, FTAS 4.0 adds targeted tests that validate ARP flush and IP update behavior when a MAC address is reused in VXLAN deployments. This helps catch hard-to-trace forwarding issues before they reach production.
What port breakout speeds does FTAS 4.0 support?
FTAS 4.0 automates dynamic port breakout scenarios across 800G, 400G, 200G, and 100G configurations. This allows teams to validate breakout changes consistently before applying them to production.
What VNI scale coverage is included in FTAS 4.0?
New L3VNI and L2VNI scale automation covers up to 4,094 VLANs. Tests validate ARP and FDB aging, forced clears, traffic recovery, and fabric resiliency during spine or uplink failures.
What framework and tooling improvements come with FTAS 4.0?
FTAS 4.0 automatically collects techsupport dumps before test cleanup runs, ensuring diagnostic data is captured whenever a test fails. It also introduces live run monitoring so teams can track test execution status in the UI without waiting for a full run to complete.
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