Issue link: https://read.uberflip.com/i/1464684
LoRaWAN ® Remote Multicast Setup Specification TS005-2.0.0 ©2022 LoRa Alliance ® Page 16 of 21 The authors reserve the right to change specifications without notice. Note 2: The end-device does not have to operate in unicast Class B 506 during multicast Class B sessions. 507 Note 3: Class C-enabled end-devices cannot participate in multicast 508 Class B sessions. LoRaWAN 1.1 end-devices should switch back to 509 Class A before enabling Class B. 510 511 The payload of the message is: 512 Table 21: McClassBSessionReq 513 Where: 514 Bits 7:2 1:0 McGroupIDHeader Fields RFU McGroupID Table 22: McClassBSessionReq McGroupIDHeader format 515 McGroupID is the identifier of the multicast group being used. 516 517 SessionTime is the start of the Class B window and is expressed as the time in seconds 518 since 00:00:00, Sunday 6 th of January 1980 (start of the GPS epoch) modulo 2 32 . Note that 519 this is the same format as the Time field in the LoRaWAN Class B beacon frame defined in 520 LoRaWAN Link Layer Specification [TS001]. SessionTime SHALL be an integer multiple 521 of 128. 522 Note: This command can only schedule Class B sessions up to about 523 194 days in the future because the McClassBSessionAns 524 TimeToStart field size is 3 bytes. 525 526 Bits 7 6:4 3:0 TimeOutPeriodicity Fields RFU Periodicity TimeOut Table 23: McClassBSessionReq TimeOutPeriodicity format 527 TimeOut encodes the maximum length in BeaconPeriods (128 seconds) of the 528 multicast fragmentation session (maximum time the end-device stays in Class B before 529 eventually reverting to Class A to save battery). 530 531 The maximum duration in seconds is 128×2 TimeOut (Example: TimeOut=8 corresponds 532 roughly to 9.1 hours). 533 Note: For Class B, TimeOut is expressed in BeaconPeriod 534 (128 seconds), whereas it is expressed in seconds for Class C. This is 535 because a Class B multicast session is heavily duty-cycled and is likely 536 to last a lot longer than a Class C session. 537 538 This is a maximum duration because the end-device's application might decide to revert to 539 Class A before the end of the session; this decision is application specific. 540 Size (octets) 1 4 1 3 1 Field McGroupIDHeader Session Time TimeOut Periodicity DLFreq DR