Issue link: https://read.uberflip.com/i/1428350
LoRaWAN Remote Multicast Setup v1.0.0 Specification ©2018 LoRa Alliance™ Page 6 of 18 The authors reserve the right to change specifications without notice. 3 Multicast group context definition 140 141 This package makes the following assumptions. 142 Inside a given end-device a multicast group is defined by the following parameters (the 143 multicast group context): 144 1. A McGroupID: an integer in [0:3], the index of the multicast group. This index is used 145 as an end-device specific shortcut to reference one of the multicast groups defined 146 inside the end-device. An end-device supports a maximum of 4 simultaneous 147 multicast groups, and a minimum of 0. 148 2. Multicast address: the 4 bytes network address of the multicast group, common to 149 all end-devices of the group. 150 3. A multicast group key (McKey) from which are derived a McAppSKey and a 151 McNwkSKey. The McKey is multicast group specific (different for every multicast 152 group), but all end-devices of a given multicast group have the same McKey 153 associated to this group 154 4. A frame counter. 155 Because the end-device can be part of up to 4 multicast groups, every multicast control 156 command MUST first define which multicast group is concerned by the command. To 157 minimize the protocol overhead, a 2-bit McGroupID shortcut is used instead of the full 4 158 bytes multicast group network address in most of the commands defined in this package. 159 An end-device MAY support up to 4 multicast groups contexts defined simultaneously. If an 160 end-device supports N simultaneous multicast group contexts where 1<=N<=4 then the 161 McGroupID can only be in the range [0:N-1]. 162 163 For example, if an end-device is designed to support only a single 164 multicast group, then this group can only have McGroupID=0. 165 166 167