Issue link: https://read.uberflip.com/i/1428395
LoRaWAN ® L2 1.0.4 Specification © 2020 LoRa Alliance ® Page 15 of 90 The authors reserve the right to change specifications without notice. 4 MAC Frame Formats 432 All LoRaWAN uplink and downlink packets carry a PHY payload (PHYPayload) starting with 433 a single-octet MAC header (MHDR), followed by a MAC payload (MACPayload), and ending 434 with a 4-octet message integrity code (MIC). 435 436 PHYPayload: 437 MHDR MACPayload MIC or 438 MHDR Join-Request 4 MIC or 439 MHDR Join-Accept 4 MIC PHYPayload structure 440 MACPayload: 441 FHDR FPort FRMPayload MACPayload structure 442 FHDR: 443 DevAddr FCtrl FCnt FOpts Frame header structure 444 445 Table 1: LoRaWAN frame format elements 446 4.1 PHY Payload (PHYPayload) 447 448 449 Size (octets) 1 7..M 4 PHYPayload MHDR MACPayload MIC Table 2: PHYPayload format 450 451 452 The maximum length M of the MACPayload field is region- and data-rate-specific and is 453 specified in [RP002]. Neither the end-device nor the Network SHALL send a frame containing 454 a MACPayload greater than the specified maximum length M over the data rate used to 455 transmit the frame. Any frame received by an end-device or a Network Server containing a 456 MACPayload greater than the specified maximum length M over the data rate used to receive 457 the frame SHALL be silently discarded. 458 4 Cf. Section 6.2.4