[OASIS Issue Tracker] (MQTT-257) Flow Control

[OASIS Issues Tracker <workgroup_mailer@lists.oasis-open.org>]

    [ https://issues.oasis-open.org/browse/MQTT-257?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=63189#comment-63189 ] 

Ed Briggs commented on MQTT-257:
--------------------------------

I've created MQTT-295 which proposes to eliminated retransmission of PUBLISH and PUBREL during the lifetime of a single transport connection. This sort of retransmission was present in MQTT 3.1, and some implementation still provide it as an option in MQTT 3.1.1.  This can break flow control because the flow control variables will be updated by the retransmission, and, if indeed transport is dropping messages, other things will break as well.  This is a follow up from the MQTT-TC conference call on 11-Aug-2016.

> Flow Control
> ------------
>
>                 Key: MQTT-257
>                 URL: https://issues.oasis-open.org/browse/MQTT-257
>             Project: OASIS Message Queuing Telemetry Transport (MQTT) TC
>          Issue Type: Bug
>          Components: futures
>    Affects Versions: 5
>            Reporter: Peter Niblett
>            Assignee: Ed Briggs
>
> Developers sometimes ask if there's a way to slow down an MQTT message sender to stop it sending PUBLISH packets faster than the receiver (be it a server or client) is able to process them.
> The receiver can apply back pressure at the TCP/IP level (if it's a TCP/IP transport) or - for QOS 1 and QOS2 - it can delay sending acks so that eventually the sender's inflight message window will fill up, but these mechanisms are a bit crude, and the receiver has no in-band way of letting the sender know what rate is acceptable to it. 
> We need to decide whether this is a problem that affects a significant number of existing or envisaged real-life applications (as opposed to performance and stress tests)



--
This message was sent by Atlassian JIRA
(v6.2.2#6258)