Fw: [mqtt-comment] MQTT protocol

[Richard J Coppen <COPPEN@uk.ibm.com>]

Hi Georges, 

Thanks for your question on MQTT as
part of the v3.1.1 Committee Specification Draft public review.
Andrew Banks - one of the Technical Committee's editors - has taken a look
into this and provided the response below.

Best regards

Richard

Richard Coppen CEng FBCS		IBM United Kingdom
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Phone:	+44 (0)1962 817164	England
e-mail:	coppen@uk.ibm.com
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Georges,

Many thanks for your feedback on the CSD.

I've been looking into this, I think the relevant section in the specification is:

1.1        Handling protocol violations
If the Client or Server encounters a transient error while processing an inbound Control Packet it MUST close the Network Connection on which it received that packet [MQTT-4.8.0-1]. If a Server detects a transient error it SHOULD NOT disconnect or have any other affect on its interactions with any other Client.

So we are saying that only the client causing the problem must be disconnected, all other clients will remain connected, the server continues to listen on its port. A future version of the protocol could extend this so that negative outcomes are sent back to the client.

I hope this addresses your concern. If you have any other questions please add a comment to the mailing list

Andrew Banks
Telephone (44) 1962 816123

----- Forwarded by Andrew Banks/UK/IBM on 05/02/2014 16:35 -----


From:        Luel Georges <Luelg@STIB.IRISNET.BE>
To:        "mqtt-comment@lists.oasis-open.org" <mqtt-comment@lists.oasis-open.org>,
Date:        03/02/2014 09:33
Subject:        [mqtt-comment] MQTT protocol
Sent by:        <mqtt-comment@lists.oasis-open.org>

---

Hi, 
  
I am a project manager and SCADA architect for the STIB in Belgium.
  
It is the company who manage all the people transportation for Brussels.
  
That means 1500 vehicles and more than 7000 people.
  
I have a comment about the new MQTT protocol. 
  
I think it is not a good idea to close the port in case of transmission
errors. 
  
I think that the protocol must be robust and throw wrong message.
  
Best regards

	Georges Luel Project Manager InfoTech - Projects IT P - SIC P Information Systems Transport Systems STIB-MIVB - rue Royale 76 Koningsstraat - Bruxelles 1000 Brussel Tel: +32 2 563 80 58 - GSM: +32 499 866 549 E-mail: luelg@stib.irisnet.be - Web: www.stib.be – www.mivb.be
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