Issue link: https://read.uberflip.com/i/1428356
LoRaWAN Fragmented Data Block Transport v1.0.0 Specification ©2018 LoRa Alliance™ Page 11 of 30 The authors reserve the right to change specifications without notice. 283 If this message was received on a multicast address, the end-device MUST check that the 284 multicast address used was enabled at the creation of the fragmentation session through the 285 McGroupBitMask field of the FragSessionSetup command. If not, the frame SHALL be 286 silently dropped. 287 Where is the fragment N over M of the session. 288 More than M fragments MAY actually be transmitted to add redundancy and packet loss 289 robustness. N is the index of the coded fragment transported. 290 M is equal to the NbFrag parameter. 291 Once the data block has been reconstructed the end-device SHALL drop any further 292 message using that fragIndex until the fragmentation session is first deleted and a new 293 fragmentation session is setup through the FragSessionSetup application command. 294 3.5 FragSessionStatusReq & Ans 295 This message can be transmitted by the server in a UNICAST or MULTICAST downlink 296 frame. 297 298 299 Size (bytes) 1 FragParam Payload FragStatusReqParam Table 14: FragSessionStatusReq 300 301 Where: 302 303 bits 7:3 2:1 0 FragStatusReqParam field RFU FragIndex Participants Table 15: FragSessionStatusReq FragStatusReqParam field 304 305 Used by the fragmentation server to request receiver end-devices to report their current 306 defragmentation status. 307 308 The receivers (in the case of multicast) SHOULD NOT answer this request all at the same 309 time because this would potentially generate a lot of collisions. The receivers MUST 310 therefore spread randomly their responses as specified by the BlockAckDelay field of the 311 FragSessionSetupReq command. 312 313 The "participants" bit signals if all the fragmentation receivers should answer or only the 314 ones still missing fragments. 315 316 Participant bit value 0 1 Only the receivers still missing fragments MUST answer the request All receivers MUST answer, even those who already successfully reconstructed the data block Table 16: FragSessionStatusReq FragStatusReqParam field participant bit 317