June 2026 FBOSS monthly summary focusing on ACL visibility, hardware-specific ACL support, testing infrastructure, and new switch-extension capabilities. Key enhancements improve correctness, observability, and release reliability, with direct business value in safer deployments and faster validation across hardware generations.

2026-05 monthly summary for facebook/fboss: Key features and changes delivered this month focused on alignment across Tomahawk ASIC generations, modernization of thrift clients, and streamlining hardware validation. Business value centers on consistency, reliability, and maintainability for production deployments while reducing validation time. Key items delivered: - PG headroom watermark feature for Tomahawk 6: Enabled by moving the feature flag from the unsupported to the supported block, aligning TH6 with TH5 behavior (commit e06110b4c37cc3d3b763d9299cedc9a1bb3b49b8). This unifies ingress priority handling and avoids regressions in traffic prioritization. - Migration of thrift clients to modern implementation: Migrated fboss/py/fboss thrift clients from py-deprecated to thrift-python, with wrapper classes that delegate to a sync client created via get_sync_client, and backward-compatible __getattr__ delegation. Updated BUCK dependencies to reflect thrift-python clients (commit 237bee8a4d4fd488cf9fa114b506dd92cef2f3e3). - Test framework migration and cleanup: Consolidated hw-test-to-agent-hw-test migrations and cleaned up obsolete tests, enabling AgentHwTest-based validation for hardware hash polarization and related tests. Notable commits include removal of HwLoadBalancerTestsV6Flowlet, HwProdInvariantTests, HwHash polarization/consistency tests, HwSplitAgentTest, and associated hw-test wiring changes (commits 661d982d..., a9f6eef..., 0b1c7ba0..., 206dbd4a...). - Ancillary improvements: Streamlined test and validation infrastructure, updated configuration and build references to support the new AgentHwTest framework, and aligned test coverage with the new validation approach. Overall impact and accomplishments: - Consistency: Tomahawk 5 and 6 behavior aligned for critical watermark feature, reducing cross-generation discrepancies. - Maintainability: Thrift client modernization reduces technical debt and simplifies future upgrades. - Validation readiness: AgentHwTest-based tests improve hardware polarization validation coverage and reliability, accelerating release readiness. - Efficiency: Reduced test suite maintenance by removing legacy tests and migrating to a unified framework. Technologies/skills demonstrated: - Thrift modernization: thrift-python, get_sync_client, wrapper-based backward compatibility, and Python client factory usage. - Build/dependency modernizations: BUCK changes and dependency mappings for updated thrift clients. - AgentHwTest framework adoption: migrations and test consolidation for hardware validation. - Code hygiene: removal of obsolete tests and clean-up of test infrastructure for faster iteration and reliability.

April 2026 FBOSS monthly summary focused on delivering robust reviewer capabilities, resilient rollback testing, and platform resource tuning. The work strengthened code review accuracy, release safety, and platform performance, enabling faster, more reliable deployments across FBOSS platforms.

In March 2026, FBOSS development delivered core CLM enhancements, deep PacketStream integration, and platform-level improvements across Ladakh and TH5, strengthening network visibility, control-plane extensibility, and reliability. The work emphasized business value through better per-port CLM metrics, richer external control integration, and more stable warm-boot behavior, while expanding test coverage to improve quality. Key achievements include a focus on CLM, PacketStream, warm-boot reliability, platform enhancements, and test automation, with concrete, measurable deliveries across code, tests, and documentation.

February 2026 (facebook/fboss) highlights: Delivered a robust rollback framework for HwSwitch with SAI, including reverse-order delta rollback per FIB changes; introduced StateDeltaApplication architecture to carry and apply delta changes across SwSwitch, HwSwitchHandler, and MultiHwSwitchHandler; plumbed deltaApplication through HwSwitch stateChangedTransaction, StateUpdate, and stateChangedImpl; added SAI_PORT_ATTR_EXT_CABLE_PROPAGATION_DELAY_MEDIA_TYPE support on XGS; expanded rollback testing for route updates/ECMP with extensive agent and spillover tests; enabled spillover tests on TH3 and aligned ARS base index for TH3. Major bugs fixed: rollback sequencing bug in HwSwitchHandler, SaiSwitch::constructSwitchStateWithFib mismatch across platforms, AgentTrafficPfcWatchdogTest resets, and related TH3 ARS/base index issues. Business value: safer rollbacks during complex FIB deltas, improved cross-platform consistency, broader coverage for ECMP/spillover scenarios, and faster recovery in incident response. Technologies: C++, fboss architecture, HwSwitch/SwSwitch, DeltaApplication model, Thrift, SAI integrations, and CI/test automation.

January 2026: Delivered rollback-enabled routing state management for SaiSwitch and hardware switches, including reverse-order delta processing, tooling to manage removed/changed routes, and tests verifying reversed-state deltas. Introduced a computeReversedDeltas utility with comprehensive unit tests covering empty, single, multiple, and partially applied deltas to ensure correct rollback behavior. Updated MP3N ECMP scale limits to support larger deployments, increasing max ECMP size and member counts. These changes improve rollback safety, routing correctness, and scalability, delivering measurable business value through safer rollouts and higher capacity in MP3N environments.

December 2025: Delivered cross-hardware ARS base index alignment for Tomahawk4 in facebook/fboss, aligning with TH5 to enable ARS groups to be configured at a fixed offset and improve hardware switch functionality. The change reduces configuration drift and enhances operational reliability in ARS-enabled deployments. Code achieved via a focused commit with review and differential revision, demonstrating collaboration across hardware teams.

Month: 2025-11 — facebook/fboss. Key features delivered: Nexthop/ECMP Routing Improvements: extended EcmpSetupHelper::programRoutes to accept disableTTLDecrement, enabling a single-state update path for ECMP route creation, preserving TTL decrement behavior across nexthop resolution, and adding platform-aware bulk removal checks for NexthopGroup management. Major bugs fixed: PumpROCE Traffic API Packet Size Fix (min IPv4 packet size adjusted to 65 to satisfy TH3 SDK requirements); PFC Watchdog Timer Granularity Fix for TH3 (apply 1ms granularity only to non-TH3 ASICs); Multi-switch Invariant Tests and DLB Verification (updated test infrastructure to support multi-switch invariant checks). Overall impact: Improved routing stability during bulk updates, reduced SDK-related packet errors and timer configuration issues on TH3, and stronger multi-switch validation for DLB. Technologies/skills demonstrated: C++, FBOSS core, EcmpSetupHelper, NexthopGroup management, SAI integration, bulk programming optimizations, multi-switch test infrastructure, platform-aware configuration, code review/differential workflows.

Concise monthly summary for 2025-10 focused on facebook/fboss. Delivered platform compatibility fixes for ARS and ACL across hardware platforms, and adjusted DLB group limits for Tomahawk5 to improve stability and SDK alignment. The work reduces ARS creation failures on unsupported systems, improves ACL compatibility on TH3, and aligns DLB group usage with internal SDK constraints, enabling broader hardware adoption and smoother operations.

September 2025 (facebook/fboss) focused on test reliability, ASIC-aware validation, and build stability. Delivered new test configurations and precision controls that improve coverage and determinism, while addressing infrastructure gaps to reduce flaky tests and enable hardware-specific validation across Chenab and related ASICs. The work enhances business value by accelerating safe changes to the data plane, reducing regression risk, and stabilizing CI pipelines for faster feedback cycles.

Monthly Summary for 2025-08 | facebook/fboss This month focused on stabilizing ARS-related features, expanding hardware validation, and strengthening route/ECMP infrastructure. Highlights include production-grade ARS Flowlet testing, loopback ARS Link State support, hardware-tested UDF_HASH production integration, FIB-based switch state construction for IPv4/IPv6 routing, and a centralized ECMP resource manager initializer. Concurrent test hygiene improvements reduced flakiness and maintenance overhead, enhancing overall reliability for production deployments.

July 2025 performance summary: Delivered impactful features, reliability improvements, and OSS integration across fboss and related projects. Focus areas included Flowlet-based networking, enhanced DLB/ECMP hashing, QoS/AI queue management, and robust test/build health. SAI compatibility was strengthened by upgrading the library to 1.16.3 across multiple repos, improving compatibility and enabling new capabilities. In addition, test stability improvements and UDF/test adjustments reduced flakiness and improved verification robustness. These efforts collectively lowered production risk, improved routing accuracy and performance, and streamlined OSS integration.

June 2025 fboss monthly summary for the facebook/fboss repository. Delivered switching-mode aware Next Hop Group (NHG) and route-management improvements, enhanced DLB resource accounting, and expanded warm-boot support. The changes improve routing fidelity, high-availability during failover, and resource efficiency in large-scale deployments, while strengthening test coverage and maintainability to accelerate issue detection and deployment confidence.

May 2025 FBoss monthly summary: Delivered dynamic ECMP switching capabilities and an expanded API surface, enabling runtime switching and more resilient routing across BCM Egress and HwSwitch paths. Implemented a core switchingMode framework, extended constructors/accessors, and comprehensive tests. Refactored state change handling to a delta-vector model, improving maintainability and performance for HwSwitch/SwSwitch in mono and multi-mode deployments. Enhanced ECMP spray logic and ACL handling to improve load balancing reliability. Hardened warm-boot resilience with switching mode state preservation and related test refactors, ensuring routing continuity after restarts. Gate-kept ECMP ID management behind a feature flag and built robust test utilities and spillover/testing scaffolding to accelerate QA. Overall, these efforts reduce downtime during reconfigurations, increase routing stability under dynamic conditions, and demonstrate strong orchestration, testing, and HW/SW integration skills.

April 2025 (2025-04) monthly summary for repository facebook/fboss. Focused on delivering robust ARS (Advanced Routing System) capabilities, strengthening ACL-driven security, and improving test coverage and CI readiness. The month emphasizes business value through more reliable policy enforcement, improved forwarding stability, and faster, safer release readiness through better test utilities and lint-driven quality improvements.

March 2025 (2025-03) fboss monthly summary: Delivered key features, fixed a regression impacting traffic policy handling, and expanded test coverage across ECMP, ArsProfile, and IPv6 flows. The work improves forwarding reliability, configurability, and maintainability across ASIC targets, translating to stronger business value through more stable traffic policies and faster risk mitigation. Key outcomes include: - ECMP routing reliability with per-packet random distribution and DL-based hardware test; updated switch configuration for ECMP random spray. - ArsProfile API quantization thresholds introduced for finer control over quantization parameters and performance. - ASIC-specific ArsProfile management modularity: SaiArsProfileManager relocated to ASIC-specific directories with per-ASIC implementations. - CHENAB IPv6 flowlet/UDF test coverage enhanced by including Ethernet type as a qualifier for IPv6 validation. - Fixed regression: Default CPU ACLs for non-SAI configurations ensured by copying default ACLs into non-SAI device configurations, improving traffic policy handling.