[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=63192#comment-63192 ] 

Jonathan Levell commented on MQTT-257:
--------------------------------------

I think I'm happy that a value of 0 is an error. The alternative is that it has a valid meaning that it only wants to send messages and not receive any - but this is an extra complication in implementation without a pressing use-case.

I think server implementations are likely to have upper bounds on what they allow clients to specify as the max limit and specifying any value larger than the (implementation defined limit) is likely to be the same as specifying the limit.

> 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)