[Afshin-Zanganeh]

StreamMerger eliminates duplicates using a bounded list of accepted sequence numbers. It has no sequence-position acceptance window or inactivity reset. This change adds a reusable recovery helper and a selectable VectorStreamMerger for simulations that need the Vector Recovery Algorithm, addressing the sequence-recovery portion of #1069.

The helper tracks received sequence positions and compares numbers modulo 65536. The merger applies recovery once per processed packet, owns a reset timer per recovery instance, and publishes cumulative diagnostic counters. Existing StreamMerger behavior and default module selection are unchanged.

Recovery grouping and window size affect delivery. Inputs sharing an instance must use the same sequence generator, and the history must cover expected sequence gaps and path-delay differences. Timer rounding and simultaneous-event ordering are documented model choices covered by focused tests.

Scope

Implements the documented IEEE 802.1CB-2017 vector recovery behavior with the IEEE 802.1CBdb-2021 forward-window correction. This covers duplicate and rogue rejection, delayed-packet acceptance, sequence wraparound, timeout reset, tagless handling and optional individual-member recovery. Latent error detection, MRA and management tables are outside this contribution.

The module reuses INET's packet-filter interfaces, stream mapping and sequence tags. It adds no on-wire format or core packet API change. It requires complete frames and backpressure=false. Recovery counters are aggregate diagnostics, not standard management tables.

Commit series

1. redundancy: add: vector sequence recovery state introduces the helper and its unit tests.
2. redundancy: add: configurable vector stream merger integrates packet processing, timers and statistics, with module and protocol tests.
3. examples: add: vector recovery demonstration and validation adds usage documentation, four network configurations.

The implementation plan is plan/pending/frer-vector-recovery.md. The protocol requirements, test traces and assertions are described in tests/protocol/frer/vector-recovery.md.

Configuration

*.*.bridging.streamRelay.merger.typename = "VectorStreamMerger"
*.*.bridging.streamRelay.merger.historyLength = 32
*.*.bridging.streamRelay.merger.resetTimeout = 10ms

Examples are in showcases/tsn/framereplication/vectorrecovery.

Validation

Linux debug and release builds of the recovery implementation passed. Both modes passed all 2 unit, 11 module and 8 protocol fixtures: 42 focused test executions. Native ASan/UBSan checks also passed, including differential transitions and multiple sequence wraps.

Tests use INET's existing opp_run_unit_tests, opp_run_module_tests and opp_run_protocol_tests runners. Exact build commands and selectors are documented in the protocol reviewer document. The showcase README gives the network commands and the recorded scalar/vector results. The change adds no VRA-specific runner and leaves existing fingerprint baselines unchanged.

The separate full-network campaign checks four scenarios in both modes and the five existing FRER fingerprint cases with the stored non-graphical ingredients. Its final result is still being collected.

[levy]

Other than the marked part, this PR is in a very good shape! Thanks!

[levy]

what is this file supposed to do in the tests/module folder?

[Afshin-Zanganeh]

@levy Thanks for pointing this out. It was a standalone post-processing script for the four showcase simulations. I removed it as it was extra thing.