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wiki:wiki3:faq_multicast_3.x [2019/03/28 11:05]
tda
wiki:wiki3:faq_multicast_3.x [2019/06/21 15:44] (current)
tda
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-===== What is Unicast and Multicast ? =====+===== What are Unicast and Multicast? =====
 Unicast messages are sent to a single end-device and multicast messages are sent to multiple end-devices. All devices of a multicast group must share the same multicast address and associated encryption keys. Unicast messages are sent to a single end-device and multicast messages are sent to multiple end-devices. All devices of a multicast group must share the same multicast address and associated encryption keys.
-All end-devices must listen to the multicast channel in order to get multicast messages (end-devices must be C-class). The best use-cases for Multicast ​is Lighting domain and Firmware update.+All end-devices must listen to the multicast channel in order to receive ​multicast messages (end-devices must be C-class). The best use-cases for Multicast ​are Lighting domain and Firmware update.
  
-===== How can I know that multicast messages are correctly received by my end-devices ? ===== +===== How can I know that multicast messages are correctly received by my end-devices?​ ===== 
-There is no ACK for Multicast messages. So we don'​t ​know if the multicast message has been received by all end-devices.+There is no ACK for Multicast messages. So from the WMC side, we cannot ​know if the multicast message has been received by all end-devices.
  
-===== What is the mantadory information ​to create a Multicast group ? ===== +===== What are the requirements ​to create a Multicast group? ===== 
-The mandatory ​information is : \\ +The mandatory ​requirements are : \\ 
-  *  a Cluster ​name +  *  a cluster ​name 
-  * a Multicast ​address: DevAddr, a 32 bit network address (must be unique and not belong to an existing end-device)\\ +  * a multicast ​address: DevAddr, a 32 bit network address (must be unique and not belong to an existing end-device)\\ 
-  * the Application ​session key (AppSKey) and Network ​session key (NWkSKey) used for frames encryption, 32 digits hexadecimal string. +  * the application ​session key (AppSKey) and network ​session key (NWkSKey) used for frames encryption, 32 digits hexadecimal string. 
-  * radio settings: a fixed frequency in MHz (float32)and a DataRate (a string formatted as "​SFxxBWyyy"​ with xx from 7 to 12 and yyy = 125/250/500 for LoRa modulation or yyy=5000 for FSK modulation)+  * radio settings: a fixed frequency in MHz (float32) and a DataRate (a string formatted as "​SFxxBWyyy"​ with xx from 7 to 12 and yyy = 125/250/500 for LoRa modulation or yyy=5000 for FSK modulation)
   * a frame counter: FCntDown   * a frame counter: FCntDown
   * the LoRaWAN MAC version: for Europe 868 MHz, select 1.0.2 MAC version and Regional parameters B revision to be compatible with WMC 2.x    * the LoRaWAN MAC version: for Europe 868 MHz, select 1.0.2 MAC version and Regional parameters B revision to be compatible with WMC 2.x 
  
 The multicast address and associated network session key and application session key must come from the application layer. \\ The multicast address and associated network session key and application session key must come from the application layer. \\
-Class-C ​Multicast ​downlinks SHALL NOT carry MAC commands.+Class-C ​multicast ​downlinks SHALL NOT carry MAC commands.
  
-===== Can several ​Muticast ​groups have the same multicast adress ? =====+===== Can several ​Multicast ​groups have the same multicast adress? =====
 Yes. The same multicast adrress can be used by several Multicast groups. Yes. The same multicast adrress can be used by several Multicast groups.
  
-===== Can end-device belong to several Multicast groups ? ===== +===== Can an end-device belong to several Multicast groups? ===== 
-Yes. end-device can belong to several ​multicast ​groups.+Yes. An end-device can belong to several ​Multicast ​groups.
  
-===== Which gateways are chosen for a C-Multicast DataDown ? =====+===== Which gateways are chosen for a C-Multicast DataDown? =====
  
-LNS selects gateways according to the dutycycle and the coverage of each gateway.+The LNS selects gateways according to the dutycycle and the coverage of each gateway.
  
-In all cases, a gateway cannot be selected if its duty cycle is over the maximum limit or if downlink is not allowed by its owner.+In any case, a gateway cannot be selected if its duty cycle is over the maximum limit or if downlink is not allowed by its owner.
  
-If end-device has never transmitted data, it won't be taken into account for the choice ​of gateways used for multicast ​DataDown.+If an end-device has never transmitted data, it won't be considered when doing the selection ​of gateways used for Multicast ​DataDown.
  
  
-===== Which gateways are choosen for a Unicast DataDown ? ===== +===== Which gateways are choosen for a Unicast DataDown? ===== 
-LNS selects gateways according to their SNR (Signal/​Noise ratio). The gateway with the higher SNR (lowest noise) is choosen in priority.+The LNS selects gateways according to their SNR (Signal/​Noise ratio). The gateway with the higher SNR (lowest noise) is choosen in priority.
  
-===== Is it possible that a end-device receive a C-Multicast DataDown from 2 different ​gateways at the same time ? ===== +===== Is it possible that a end-device receive a C-Multicast DataDown from multiple ​gateways at the same time? ===== 
-For the moment, this case is not managed.+This case is not managed ​by the LNS yet.
  
  
wiki/wiki3/faq_multicast_3.x.1553767522.txt.gz · Last modified: 2019/03/28 11:05 by tda