OASIS Message Queuing Telemetry Transport (MQTT) TCIcon indicating the project type

OASIS Message Queuing Telemetry Transport (MQTT) TC

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  1. OASIS Message Queuing Telemetry Transport (MQTT) TC
  2. MQTT-58

How many messages are received for overlapping subscriptions?

    Details

    • Type: Improvement
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 3.1.1
    • Fix Version/s: 3.1.1
    • Component/s: core
    • Labels:
      None
    • Proposal:
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      From line 833 "Publish" WD12. Insert the following text

      When clients make subscriptions with topic filters that include wild cards, it is possible for a client's subscriptions to overlap so that a published message might match multiple filters. In this case the server MUST deliver the message to the client respecting the maximum QoS of all the matching subscriptions. In addition, the server MAY deliver further copies of the message, one for each additional matching subscription and respecting the subscription's QoS in each case.

      From line 966 "Subscribe Response" (In addition to wording relating to issue MQTT-59, add the following text)

      Where the subscription is not identical to an existing subscription, a new subscription is created and all matching retained publications are sent.

      Show
      From line 833 "Publish" WD12. Insert the following text When clients make subscriptions with topic filters that include wild cards, it is possible for a client's subscriptions to overlap so that a published message might match multiple filters. In this case the server MUST deliver the message to the client respecting the maximum QoS of all the matching subscriptions. In addition, the server MAY deliver further copies of the message, one for each additional matching subscription and respecting the subscription's QoS in each case. From line 966 "Subscribe Response" (In addition to wording relating to issue MQTT-59 , add the following text) Where the subscription is not identical to an existing subscription, a new subscription is created and all matching retained publications are sent.
    • Resolution:
      Hide

      Fixed in WD14

      Show
      Fixed in WD14

      Description

      A client has subscribed to a/+ with QoS2 and a/b with QoS1. A message is published to a/b. Does the client receive one or two messages? If one which QoS would apply?

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          9 older comments
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          coppen Richard Coppen (Inactive) added a comment -

          TC Approve proposal - TC call 10.10.2013
          Proposed Allan Stockdill-Mander, Seconded Raph Cohn

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          coppen Richard Coppen (Inactive) added a comment - TC Approve proposal - TC call 10.10.2013 Proposed Allan Stockdill-Mander, Seconded Raph Cohn
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          coppen Richard Coppen (Inactive) added a comment -

          Checked in WD15

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          coppen Richard Coppen (Inactive) added a comment - Checked in WD15
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          andrew_banks Andrew Banks (Inactive) added a comment -

          Reopened because 253. was closed.

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          andrew_banks Andrew Banks (Inactive) added a comment - Reopened because 253. was closed.
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          andrew_banks Andrew Banks (Inactive) added a comment -

          MQTT253 (add subscription ids) tried to address this but was abandoned. Other ways to address this, might be:

          • Require that a server that sends multiple messages should mark all but the first message as repeat a message.
          • A server should announce on CONNACK that it is going to send multiple responses when needed.
          • The server should add a unique identifier to a publish message so that the client can eliminate the repeat messages
            if it needs to.
          Show
          andrew_banks Andrew Banks (Inactive) added a comment - MQTT253 (add subscription ids) tried to address this but was abandoned. Other ways to address this, might be: Require that a server that sends multiple messages should mark all but the first message as repeat a message. A server should announce on CONNACK that it is going to send multiple responses when needed. The server should add a unique identifier to a publish message so that the client can eliminate the repeat messages if it needs to.
          Hide
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          andrew_banks Andrew Banks (Inactive) added a comment -

          Above comment added in error... See MQTT-217

          Show
          andrew_banks Andrew Banks (Inactive) added a comment - Above comment added in error... See MQTT-217

            People

            • Assignee:
              andrew_banks Andrew Banks (Inactive)
              Reporter:
              al.s-m Allan Stockdill-Mander (Inactive)
            • Watchers:
              1 Start watching this issue

              Dates

              • Created:
                Updated:
                Resolved: