[OASIS Issue Tracker] (MQTT-268) MQTT-SN Feature: Sleeping Clients

[ https://issues.oasis-open.org/browse/MQTT-268?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=62237#comment-62237 ] 

Ian Craggs edited comment on MQTT-268 at 4/8/16 7:18 PM:
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Sleeping clients only make sense in a connectionless, non TCP world.   The "offline keepalive" part of this sleeping client behaviour is dealt with in the proposal for issue 263 - Simplified State Management.  Sleeping clients in MQTT-SN do not need to reconnect, they just send a PING packet to the server to start receiving any queued messages.  This works because the server determines the source of the incoming packet by its address - no connection is set up.  Over TCP, the client would have to open a socket again and send an MQTT connect packet to inform the server which client was communicating with it.  Unless the client kept the socket open, but I think that would negate one of the advantages - power saving on the part of the client.




was (Author: icraggs):
Sleeping clients only make sense in a connectionless, non TCP world.   The "offline keepalive" part of this behaviour is dealt with in the proposal for issue 263 - Simplified State Management.  Sleeping clients in MQTT-SN do not need to reconnect, they just send a PING packet to the server to start receiving any queued messages.  This works because the server determines the source of the incoming packet by its address - no connection is set up.  Over TCP, the client would have to open a socket again and send an MQTT connect packet to inform the server which client was communicating with it.  Unless the client kept the socket open, but I think that would negate one of the advantages - power saving on the part of the client.



> MQTT-SN Feature: Sleeping Clients
> ---------------------------------
>
>                 Key: MQTT-268
>                 URL: https://issues.oasis-open.org/browse/MQTT-268
>             Project: OASIS Message Queuing Telemetry Transport (MQTT) TC
>          Issue Type: Improvement
>          Components: futures
>    Affects Versions: 3.1.1
>         Environment: Connectionless network transports
>            Reporter: Ian Craggs
>
> The MQTT-SN specification allows clients to save power by "sleeping".  This is achieved by the client sending a disconnect packet with a duration field - this is the only message format change needed for this function.  Messages are queued for the client, and delivered when a ping is received by that client. 



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