[OASIS Issue Tracker] Commented: (MQTT-16) Reserve $SYS topic name

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

    [ http://tools.oasis-open.org/issues/browse/MQTT-16?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=33533#action_33533 ] 

Raphael Cohen commented on MQTT-16:
-----------------------------------

I'd second Alex's comments above. I'm very hesitant about having special topics. Even if we reserve '$', there are still interop gotchas waiting to happen. For instance, what might happen if a broker also bridges to SMTP or HTTP or the like? We can be 'reasonably sure' for some of the more obvious protocols there isn't overlap, but we can't ever be sure. More sure requires usually more obscure UTF-8 characters - NUL or one of the private use area characters - but there's still a potential doubt, and other problems then arise...

If we *have* to do anything, then the most we should say is that topics starting '$SYS' (or '$') *MAY* be special for some implementations / considered reserved.

And once we have special topics we then need special messages and digital signatures and... it goes on for months.

> Reserve $SYS topic name
> -----------------------
>
>                 Key: MQTT-16
>                 URL: http://tools.oasis-open.org/issues/browse/MQTT-16
>             Project: OASIS Message Queuing Telemetry Transport (MQTT) TC
>          Issue Type: Improvement
>          Components: core
>    Affects Versions: 3.1.1
>            Reporter: David Locke
>             Fix For: 3.1.1
>
>
> Many MQTT implementations today use $SYS as the head of a topic string for use in administration  (configuration, operations, monitoring).   
> Can the $SYS or a similar topic name be reserved for future use ?   As $SYS is already used by a number of servers using a different top level topic would avoid conflicts. 
> Would be good to collect ideas for a $SYS topic space.  These ideas could initially go into a non-normative document but with potential for inclusion in a future spec.  The intent being servers can implement  some aspects of administration and monitoring in a consistent way
> Some examples:
> - Admin action like "unretain" a retained topic   e.g. $SYS/topic/unretain    (payload is the topic to unretain)
> - Client wishes to query what subscriptions it has made    e.g. $SYS/client/getsubs  (topic is clientid)
> - Client wishes to query how many messages are queued up awaiting delivery e.g. $SYS/client/getNoQueuedMessages  
> - Query the  state of the MQTT server e.g. $SYS/server/getStatus 
> These examples should not be taken literally they are purely to show the type of things a $SYS topic space could be used for.

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: http://tools.oasis-open.org/issues/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira