Issue link: https://read.uberflip.com/i/1539840
Developing LoRaWAN Devices Technical Recommendation TR007-1.1 ©2021-2025 LoRa Alliance ® Page 11 of 28 The authors reserve the right to change documents without notice. 4 LoRaWAN Protocol Stack 319 4.1 Join Procedure 320 4.1.1 Description 321 Only an end-device SHALL initiate the Join Procedure. Use of the Join-Request SHOULD only 322 be used after commissioning a factory reset, loss of connectivity with the network, when one 323 of the frame counters has reached its maximum value, or new session keys are generated for 324 security reasons. 325 Join Requests create additional work for the Network Server, Join Server, and Application 326 Server, as well as additional network traffic to exchange key material, etc. Limiting Join 327 Requests will reduce unnecessary downlink and MAC command traffic. 328 4.1.2 Recommended Practice 329 If the device is powered down completely, it SHOULD store the values described in Section 330 4.13 for use when it powers up again. For a static device, there may be a network operator 331 requirement to occasionally trigger a Join Request message, allowing them to regenerate their 332 network and application session keys, but this SHOULD be limited to once a month at most. 333 Transmission of the Join-Request is governed by the retransmission back-off procedure 334 specified in the LoRaWAN Link Layer specification. This includes the case when the end- 335 device initiates the Join Procedure due to the temporary loss of power. In some end-devices, 336 as the power system nears depletion, the end-device retains enough charge to transmit an 337 uplink (Join-Request), but the act causes a brown-out reset of the host CPU/MCU. The end- 338 device SHALL guarantee that the back-off duty cycle is observed even in this condition. 339 In LoRaWAN 1.1+, the network MAY request the end-device initiate the Join Procedure, which 340 may be required to refresh session keys or to reallocate DevAddr. As LoRaWAN 1.0.x does 341 not support this ability, the end-device SHOULD support an application-layer means of doing 342 so. 343 4.2 Fixed Channel Plan Join Process Optimization 344 4.2.1 Description 345 The gateway in range of the end-device may be operating on 64 or more channels or on fewer 346 channels due to limitations of the deployed gateway radios. Optimizing the Join process will 347 typically allow the end-device to connect in fewer attempts than when using a purely random 348 or purely sequential channel selection process. 349 4.2.2 Recommended Practice 350 In the fixed channel regions of US915 and AU915, there are eight eight-channel banks in a 351 64-channel gateway, each with eight 125 KHz channels plus one 500 KHz channel. Join 352 Request attempts using US915 SHOULD be at DR0 for the 125 KHz channels and DR4 for 353