[GSoC 2026] Flent Application API Integration - Weeks 6 & 7 Update

[KEDAR KISAN]

Hii everyone,

Here is a brief progress update for Weeks 6 and 7 of the Flent Application API Integration project. During these weeks, I worked on improving the Flent application and its test suite based on suggestions and feedback from mentors.

1. Configurable File Output & Self-Contained Tests: Added the OutputFilename attribute for custom output paths and fixed metadata formatting. Reorganised the test suite, replacing six order-dependent tests with four self-contained cases. Tests now use CreateTempDirFilename() to isolate outputs in runner-managed directories, permanently preventing stale-file false positives.

2. Deterministic Timestamps: Fixed non-deterministic output and timing differences by using a single time reference . added the T0 attribute (defaulting to a fixed epoch) for byte-for-byte reproducible runs, and a UseWallClockT0 flag for testbed comparisons. Restored true microsecond precision using floating-point math.

3. DSCP/ToS Verification: Verified that Tos attribute support in the PacketSink application works correctly, ensuring TCP ACKs successfully carry the expected DSCP priority tags for RRUL classes.

4. Protected Macro Resolution: Resolved NS_TEST_ASSERT compiler access issues by introducing a FlentTestCase base class, allowing tests to cleanly share integrity verification logic via inheritance.

5. Metadata Enrichment: Expanded the generated JSON metadata to better mimic real Flent testbed outputs, dynamically populating fields like LOCAL_HOST and TITLE.

6. Codebase Cleanup: updated the codebase to follow ns-3 CI/CD and coding standards, including clang-format and clang-tidy fixes, SPDX license identifiers, standardized Doxygen @ tags, and the removal of legacy Emacs modelines.

You can view the full details and weekly breakdown of the project using the project links below:

Repository: https://gitlab.com/k.kedar/ns-3-dev
Working branches: GSoC-2026-flent-application and nlohmann-json

ns-3 Wiki: https://www.nsnam.org/wiki/GSOC2026Flent

GSoC Page: https://summerofcode.withgoogle.com/programs/2026/projects/PCXPdFoD

Best Regards,
Kedar

[KEDAR KISAN]

Hi everyone,

A quick follow-up to my previous update: I used Google Gemini to help draft some parts of my previous update email. I wanted to disclose this to ensure compliance with the ns-3 AI policy. 

I’ll also update my recent commit messages to include the appropriate (Assisted-by:) trailer wherever I used AI tools.

Best regards,
Kedar