Which CoAP specifications and options are supported?

It decodes RFC 7252 message headers, tokens, and standard options (Uri-Path, Content-Format, etc.), RFC 7641 Observe options, and RFC 7959 Block1/Block2 options.

How does the tool handle LwM2M TLV payloads?

It parses OMA §7.4.4 TLV structures, identifying Object Instances, Resources, and Multiple Resource Instances while resolving standard IDs for Device, Server, Firmware, and Location objects.

Can it parse CoAP messages transported over SMS?

Yes. It parses 3GPP TS 23.040 SMS-DELIVER TP-UD payloads and uses UDH IEI 0x05 16-bit application port addressing (ports 5683/5684) to unwrap the inner CoAP packet.

What hex formatting is accepted?

Raw hex strings are accepted one per line. Spaces, colons, and '0x' prefixes are ignored automatically during parsing.

What does the Auto detect decode mode check?

Auto detect evaluates each packet sequentially against DTLS record structures, CoAP headers, SMS-UDH envelopes, LwM2M TLV layouts, and CoRE link-format strings.

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NB-IoT LTE-M Cat-M1 CoAP LwM2M Cellular IoT Packet Analyzer

Decode hex captures from cellular IoT devices: CoAP headers/options (block-wise, Observe), LwM2M TLV object trees with registry names, SMS-DELIVER UDH port addressing unwrapping CoAP-over-SMS, link-format registrations and DTLS record summaries.

Details

What this tool helps you do

Paste one hex string per line (spaces/colons ignored; prefix "label=…" to name a packet; "#" lines are comments). Auto-detection walks DTLS → CoAP → SMS-UDH → LwM2M TLV → link-format.

Decoders follow the specs byte-for-byte: CoAP per RFC 7252 (Ver/T/TKL/Code/MID/Token, option delta+length nibbles with 13/14 extensions), block options per RFC 7959 (NUM = val>>4, M = val&8, size = 2^(SZX+4)), Observe per RFC 7641; LwM2M TLV per OMA §7.4.4 (type byte bits 7-6 = object instance / resource instance / multiple resource / resource, bit 5 = identifier width, bits 4-3 = length encoding, bits 2-0 = inline length) with Device/Server/Firmware/Location resource names; SMS-DELIVER per 3GPP TS 23.040 including semi-octet timestamps and UDH IEs (IEI 0x05 16-bit application ports 5683/5684 = CoAP/coaps); DTLS record headers per RFC 9147 with resumption notes. Content formats use the IANA registry (11542 = lwm2m+tlv; legacy 1.0 stacks emitted 110/111/112 — annotated).

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packets: label=registration 4202716daabbb272641200283c65703d6e622d696f742d3031066c743d333030ff3c2f332f303e2c3c2f342f303e label=device-read 60451234c22d16ffc800144f70656e204d6f62696c6520416c6c69616e6365c801164c69676874776569676874204d324d20436c69656e74c80209333435303030313233c303312e30c10964 decodeMode: auto showBytes: false

NB-IoT LTE-M Cat-M1 CoAP LwM2M Cellular IoT Packet Analyzer

What this tool helps you do

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Key facts

Overview

When to use

How it works

Use cases

Examples

1. Analyzing an LwM2M Registration and Sensor Read Session

2. Debugging CoAP-over-SMS Wake-Up Packets

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