[GSoC 2026] Flent Application API Integration - Week 2 Report
KEDAR KISAN
Hi everyone,
Here is my progress for Week 2 of the Flent Application API Integration project.
Week 2 Progress:
1. ProcessRawValues Interpolation Fixes
Fixed correctness bugs in the ProcessRawValues time-series interpolation.
Corrected an inverted logic branch so maxDist tightening only applies during extrapolation. The C++ port now perfectly matches the upstream Flent aggregators.py behavior for both perfectly aligned and jittered data.
2. Netns Validation Testbed Setup
Set up a Linux Network Namespace (netns) testbed and successfully ran Flent RRUL tests with netserver isolated.
Generated .flent.gz files (visualized via the Flent GUI).
3. DSCP Bidirectional Marking (RRUL)
Discovered that RRUL DSCP marking was only applying to the sender (BulkSendApplication); TCP ACKs (PacketSink) and UDP echo replies (UdpEchoServer) were returning as default CS0.
Fixes: Resolved the UDP echo reply marking locally using the existing Tos attribute in UdpEchoServer. I am currently preparing a patch to add Tos support to SinkApplication (mirroring SourceApplication) to fix the TCP ACK marking.
4. Cross-Version Testing
Testing the flent-application against different ns-3 releases from ns-3.36 to ns-3.48 to identify when specific test case in flent-application-test-suite discrepancies emerged.
Utilizing git bisect method to systematically narrow down the search space whether these variations came from past structural changes in the core engine or updates within the TCP stack behavior over the last few releases.
Project Links:
- Repository: https://gitlab.com/k.kedar/ns-3-dev (Working Branch: GSoC-2026-flent-application, nlohmann-json).
ns-3 wiki: https://www.nsnam.org/wiki/GSOC2026Flent
GSoC Page: https://summerofcode.withgoogle.com/programs/2026/projects/PCXPdFoD