Protocol Decoder API
Decode RRC and NAS protocol messages programmatically. Native C++ ASN.1 engine, multi-RAT support (2G/3G/4G/5G NR), structured JSON output.
What the API Decodes
RRC Messages
Radio Resource Control messages for 2G GSM (RRNP), 4G LTE (TS 36.331) and 5G NR (TS 38.331). Full ASN.1 UPER decoding with support for CellGroupConfig, MeasurementReport, RRCReconfiguration, and all standard logical channels.
NAS Messages
Non-Access Stratum messages for LTE EPS (TS 24.301) and 5G NR (TS 24.501). Covers EMM, ESM, 5GMM, 5GSM procedures including Attach, Registration, PDU Session Establishment, and Authentication.
Quick Start
# Decode an RRC hex frame
curl -X POST "https://decoder.hicelltek.com/api/decode" \
-H "Content-Type: application/json" \
-d '{"hex": "28183A1AA8100300", "channel": "DL-DCCH"}'
# Response includes full ASN.1 decoded structure
{
"protocol": "LTE-RRC",
"channel": "DL-DCCH",
"message_type": "RRCConnectionReconfiguration",
"decoded": {
"rrc-TransactionIdentifier": 0,
"criticalExtensions": {...}
},
"raw_asn1": "..."
} Response structure shown for illustration. Decoded output depends on the input frame.
Key Features
Multi-RAT
2G GSM, 3G UMTS, 4G LTE, 5G NR. Automatic RAT detection from hex input.
3GPP Release 17
ASN.1 definitions updated to 3GPP Release 17. Supports latest IEs and extensions.
Batch Mode
Decode multiple frames in a single API call. Process log files programmatically.
LTE→NR Tunnel
Automatic extraction and decoding of NR CellGroupConfig embedded in LTE RRCConnectionReconfiguration.
JSON Output
Structured JSON response for easy integration. Tree view or flat output modes.
Channel Detection
Auto-detect logical channel (DL-DCCH, UL-DCCH, BCCH-DL-SCH, etc.) from frame content.
Common Use Cases
Automated Log Analysis
Parse QMDL or PCAP logs and decode L3 messages for automated QoS reporting and anomaly detection.
CI/CD for Network Tools
Integrate protocol decoding in your test pipelines. Validate expected signaling behavior automatically.
Research & Education
Decode protocol samples for academic research, student labs, and training material generation.
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