Subject: [OPSAWG] syslogMsgNotification, syslog-msg-mib-01

From: WashamFan <[email-masked]>
Date: Thu, 19 Feb 2009 19:17:01 +0800

Hi,

para 2, description of syslogMsgNotification, page13 :

"Implementations may add syslogMsgSDParamValue objects as long
        as the resulting notification fits into the size constraints
        imposed by the implementation environment and the notification
        message size constraints imposed by maxMessageSize [RFC3412]
        and SNMP transport mappings."

so syslogMsgSDParamValue could be polled by snmp users?
Are users expected to traverse all entries in syslogMsgSDTable?
I don't think users can be sure they've got all SDEs in a syslog
message without traversing all entries in syslogMsgSDTable.

washam

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From: Juergen Schoenwaelder <[email-masked]>
Date: Thu, 19 Feb 2009 12:58:57 +0100

> message without traversing all entries in syslogMsgSDTable.

With the new indexing scheme, you can easily skip over params you have
already received in the notification. If that last notification
varbind is of the form syslogMsgSDParamValue.X.N."last"."thing", you
can do a getnext/getbulk on syslogMsgSDParamValue.X.N. and should get
additional params (e.g. syslogMsgSDParamValue.X.N+1."some"."thing") or
you get something that does not belong to the syslog message in
question.

/js

-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: +49 421 200 3587         Campus Ring 1, 28759 Bremen, Germany
Fax:   +49 421 200 3103         <http://www.jacobs-university.de/>

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From: WashamFan <[email-masked]>
Date: Mon, 23 Feb 2009 15:15:24 +0800

>  you get something that does not belong to the syslog message in

So there are some assumptions:
1) At least one syslogMsgSDParamValue exists in notification, what if there
is no syslogMsgSDParamValue but sdparams bit is set?
2) syslogMsgSDTable entries belonging to the same syslogMsgIndex MUST 
be stored consecutively.

In your example, you getnext until you get something that does not belong
to the syslog message in question. What does 'somthing' refer to? next entry
belonging to another syslogMsgIndex or access control denied error?

In new indexing schema, what should be put in syslogMsgSDEntry INDEX
clause? It remains the same or only helds 'syslogMsgIndex' and
'syslogMsgSDParamIndex'?

washam

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---

From: Juergen Schoenwaelder <[email-masked]>
Date: Mon, 23 Feb 2009 08:25:26 +0100

> is no syslogMsgSDParamValue but sdparams bit is set?

You can still construct a GetNext with syslogMsgSDParamIndex=0.

> 2) syslogMsgSDTable entries belonging to the same syslogMsgIndex MUST 

They can be stored in whatever way you like to store them. The
instance identifier however ensure that the lexicographic ordering is
in increasing order of syslogMsgSDParamIndex.

> belonging to another syslogMsgIndex or access control denied error?

GetNext never returs an access control denied error. You iterate until
you get something that does not belong to the syslog message in
question - it might be a syslogMsgSDParamName of a different syslog
message or something completely different.

> clause? It remains the same or only helds 'syslogMsgIndex' and

    INDEX { syslogMsgIndex, syslogMsgSDParamIndex,
            syslogMsgSDID, syslogMsgSDParamName }

You still need to know the SDID and the name of the param in order to
make sense of a value. I just changed the order of the INDEX
components.

/js

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From: WashamFan <[email-masked]>
Date: Wed, 25 Feb 2009 13:09:34 +0800

Hi,

I am a still confused about this. I am not a SNMP
expert, you know, so maybe I missed something I don't know.

See below.

>  You can still construct a GetNext with syslogMsgSDParamIndex=0.

Yes I can start syslogMsgSDParamIndex with 0, but I have no idea
what values of 'syslogMsgSDElementName' and 'syslogMsgSDParamName'
are. If I initiate a request like:
  GetNextRequest ( syslogMsgSDParamValue.X.0)
Could it return like:
  Response ( syslogMsgSDParamValue.X.0."some"."thing"="value" )
?

>  message or something completely different.
 
You iterate until something belonging to a different syslog message, is it
relevant to access control? What if 'something' here is not supposed to
be red by you?

washam

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From: "David Harrington" <[email-masked]>
Date: Wed, 25 Feb 2009 00:58:22 -0500

Hi,

If you are not allowed to access it, it will not be returned; it will
go to the next thing you can see.

dbh 

> -----Original Message-----
> From: [email-masked] 
> [mailto:[email-masked]] On Behalf Of WashamFan
> Sent: Wednesday, February 25, 2009 12:10 AM
> To: [email-masked]
> Cc: [email-masked]
> Subject: Re: [OPSAWG] syslogMsgNotification, syslog-msg-mib-01
> 
> Hi,
> 
> >  > 1) At least one syslogMsgSDParamValue exists in 
> notification, what 
> > if there
> >  > In your example, you getnext until you get something 
> that does not 
> > belong
> >  > to the syslog message in question. What does 'somthing' 
> refer to? 
> > next entry

---

From: Juergen Schoenwaelder <[email-masked]>
Date: Wed, 25 Feb 2009 11:39:23 +0100

>   Response ( syslogMsgSDParamValue.X.0."some"."thing"="value" )

It will return something like:

Response ( syslogMsgSDParamValue.X.1."some"."thing"="value" )

Note that 0 is not a legal value for syslogMsgSDParamIndex but you can
happily send it in a request. This is one of the features of SNMP: you
can construct arbitrary OIDs and the agent returns the next accessible
instance in lexicograhic order. This allows us to ask questions with
incomplete instance identifiers.

/js