Re: NETCONF Minutes for IETF 67 [draft 1]

[Martin Bjorklund <mbj@tail-f.com>]

Andy Bierman <ietf@andybierman.com> wrote:
> 2.1) StreamList Design
> 
> The group discussed the StreamsList construct introduced
> in the -04 draft.  This is a list of 1 to N stream names that
> should be combined by the agent to produce the notification
> output for a particular session.

[...]

> Cons:
>  - Streams can have different data formats, and some combinations
>     may not make sense, or the agent may not be capable of combining
>     them (i.e., the reason streams exist in the first place.)
>  - There is no simple way for the manager to know which combinations
>    are permitted

I don't understand this argument.  Maybe I don't understand how the
streams are supposed to work at all...  I thought that the idea is
that each <notification> is a complete XML instance document.  For
example

  <notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
    <my-event xmlns="http://example.com/event/1.0";>
       <!-- any valid XML here -->
    </my-event>
  </notification>

or

  <notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
    <syslog xmlns="http://ietf.org/netconf/syslog/1.0"/>
       Jun 11 21:34:52  dent chassisd[2971]:
        CHASSISD_IFDEV_DETACH_ALL_PSEUDO:
        ifdev_detach(pseudo devices: all)
    </syslog>
  </notification>

or

  <notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0">
    <snmp xmlns="http://example.com/snmp"/>
       <!-- clever representation of an snmp trap here -->
    </snmp>
  </notification>

etc.

Why would it be difficult for the agent or manager to mix these on a
single subscription?

>  - The same system event can be conveyed in different ways, across
>    multiple streams.  Manager-selected combinations of streams
>    would either create duplicate notifications or require complex
>    duplicate suppression

So suppose the manager want to subscribe to the snmp and syslog
streams, and these contain some duplicate events.  If you can't
subscribe to more than one stream, you'd open two sessions.  You will
still get the duplicate events.  So I don't understand why this is an
argument agains streamslist.


This being said, I don't have a strong opinion on this issue.  I just
don't understand the arguments.



/martin


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