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+# Requirements: NetSynth
+
+**Defined:** 2026-03-27
+**Core Value:** Network traffic patterns are instantly recognizable as distinct sounds — a ping sounds different from HTTPS noise, which sounds different from a port scan.
+
+## v1.2 Requirements
+
+Requirements for extended protocol coverage milestone. Each maps to roadmap phases.
+
+### Cleanup
+
+- [ ] **CLEAN-01**: Remove stale `NumLayers` constant and hardcoded frequency range test assertions that would block new class additions
+
+### Protocol Coverage
+
+- [ ] **PROTO-01**: Add Mail family protocols: IMAP (143/993), POP3 (110/995), SMTP-submission (587)
+- [ ] **PROTO-02**: Add File Transfer family protocols: FTP (20-21), SMB/CIFS (445), TFTP (69)
+- [ ] **PROTO-03**: Add Remote Access family protocols: RDP (3389), Telnet (23), VNC (5900)
+- [ ] **PROTO-04**: Add Database family protocols: MySQL (3306), PostgreSQL (5432), Redis (6379), MongoDB (27017)
+- [ ] **PROTO-05**: Add Discovery family protocols: mDNS (5353), SSDP/UPnP (1900), SNMP (161-162)
+- [ ] **PROTO-06**: Add VoIP family: SIP (5060/5061)
+- [ ] **PROTO-07**: Add Web family extension: QUIC/HTTP3 (UDP 443)
+- [ ] **PROTO-08**: Add Infrastructure family protocols: LDAP (389/636), Kerberos (88), Syslog (514)
+- [ ] **PROTO-09**: Existing 10 protocol classifications remain unchanged — no regression in rule matching behavior
+
+### Frequency Design
+
+- [ ] **FREQ-01**: All traffic classes (existing + new) are redistributed into group-coherent frequency bands using musical interval ratios (not fixed Hz steps)
+- [ ] **FREQ-02**: Within-family protocols are separated by at least a major second interval (ratio 1.122) to avoid critical band masking
+- [ ] **FREQ-03**: The full frequency allocation table is designed and documented before any FreqConfig code is written
+- [ ] **FREQ-04**: Auto-assign frequency range for user custom classes is updated to avoid collision with new built-in frequencies
+
+### Group System
+
+- [ ] **GRP-01**: Each traffic class belongs to a named group (Infrastructure, Web, Mail, File Transfer, Remote Access, Database, Discovery, VoIP)
+- [ ] **GRP-02**: `--print-config` output organizes classes by group with section headers
+- [ ] **GRP-03**: Users can define `[groups]` in TOML config to reassign protocols to different sound families
+- [ ] **GRP-04**: FreqConfig gains a `Group` field that drives group-aware frequency allocation and config output
+
+## Future Requirements
+
+Deferred to later releases.
+
+### Dynamic Protocol Detection
+
+- **DYN-01**: RTP voice/video payload detection (dynamically negotiated ports — cannot use port-based rules)
+- **DYN-02**: Application-layer protocol detection via DPI for ambiguous ports
+
+### Audio Tuning
+
+- **TUNE-01**: User can configure time window duration via `--window` flag
+- **TUNE-02**: User can configure output duration when reading pcap files via `--duration` flag
+
+## Out of Scope
+
+| Feature | Reason |
+|---------|--------|
+| RTP payload detection | Dynamically negotiated ports; needs DPI, not port rules |
+| mDNS multicast group join | Would require raw socket changes; port 5353 classification is sufficient |
+| Protocol-specific metadata extraction | Beyond classification scope; tool sonifies, not inspects |
+| Real-time audio playback | File output only — established v1.0 constraint |
+| GUI config editor | CLI-only tool; TOML is human-editable |
+
+## Traceability
+
+Which phases cover which requirements. Updated during roadmap creation.
+
+| Requirement | Phase | Status |
+|-------------|-------|--------|
+| CLEAN-01 | TBD | Pending |
+| PROTO-01 | TBD | Pending |
+| PROTO-02 | TBD | Pending |
+| PROTO-03 | TBD | Pending |
+| PROTO-04 | TBD | Pending |
+| PROTO-05 | TBD | Pending |
+| PROTO-06 | TBD | Pending |
+| PROTO-07 | TBD | Pending |
+| PROTO-08 | TBD | Pending |
+| PROTO-09 | TBD | Pending |
+| FREQ-01 | TBD | Pending |
+| FREQ-02 | TBD | Pending |
+| FREQ-03 | TBD | Pending |
+| FREQ-04 | TBD | Pending |
+| GRP-01 | TBD | Pending |
+| GRP-02 | TBD | Pending |
+| GRP-03 | TBD | Pending |
+| GRP-04 | TBD | Pending |
+
+**Coverage:**
+- v1.2 requirements: 18 total
+- Mapped to phases: 0 (pending roadmap)
+- Unmapped: 18
+
+---
+*Requirements defined: 2026-03-27*
+*Last updated: 2026-03-27*