Hi,

I have written a couple of probes that would greatly benefit from more
powerful table manipulation.  For example, my Novell NetWare volume
monitoring probe needs to use the volume index number to look up the
volume information, instead of being able to use the name of the volume.
 The problem is that there's no easy way to figure out the index
(without either looking it up with an SNMP browser, or trying index
numbers until you get the right one), and also sometimes the index
number of a volume will change when you add, delete or mount/dismount a
volume.

Here's my suggestion:
The probe would have a field for entering the volume name.

Then the probe would iterate over the appropriate table until it finds
the name.  If it can't find the name, there should be an error mechanism
that the probe can use to set an alarm state.

Once it finds the name it uses this to figure out the index number. 
And then the rest of the probe continues as before.

The MIB I'm referring to is in NWSERVER.MIB, and the OID to the table
is .1.3.6.1.4.1.23.2.28.2.14.1.  This MIB file can be found on your
NetWare server in sys\system\nma\mibs, and in lots of other places on
the Web.  Try Google or
http://support.novell.com/cgi-bin/search/searchtid.cgi?/2971008.htm
.

The probe I'm referring to is on the probe download page (
http://www.intermapper.com/contrib/customprobes.html ).  Note that most
of the probes I have posted there would benefit from the ability to look
up an index number from a name.

There's another class of OID lookups that sometimes come in handy. 
That's where you take some information and perform calculations on it to
generate an OID string.  For example, some switches have a MIB that lets
you look up what port a given MAC address is attached to in one step. 
You take the MAC address, convert the six hex bytes into six dotted
decimals, and tack that onto the end of an OID.  There are other
examples where you take an ASCII string or an IP address and do the same
thing.  You might be able to add a function or three that can convert
data into OID-formatted strings.  Or, you could provide access to a
scripting language like Perl from inside a probe file, which would give
us the ability to do almost anything.

Let me know if you want specific examples of this calculated-OID
technique.  

Later,

Doug


-- 
Doug Weathers

Information Technology
Network Administrator
Cascade Healthcare Community
2500 NE Neff Road
Bend, OR 97701
http://www.scmc.org

mailto:[EMAIL PROTECTED]

Desk: 541-383-6846
Cell:    541-480-0919

>>> [EMAIL PROTECTED] 4/20/2005 6:25:52 AM >>>
Folks:

--- Steve Foster wrote:
One for the developers, custom probe writers.....

Are there any plans to permit tables in custom probes? For example like
the
storage status within the host resources probe.

Has anyone got any reccomendations for how to implament a probe that
would
extract useful information out of a table, where the the table is
ordered
differently between hosts.
--- end of quote ---

Yes, we're beginning to think seriously about tables in probes. We have
some
general ideas about how to go about it, but it would help us enormously
to get a
sense of what it would mean to have a custom SNMP probe facility that
"handles
tables". 

Specifically, we are looking for examples of equipment that stores data
in
tables, and how you'd like InterMapper to retrieve/compare/display
that
information. If you've ever thought about making a probe that processed
tables,
please tell us:

-       What equipment was involved? What tables and what fields of
those tables are
interesting?
-       Should InterMapper process all the rows of the table
identically?
-       If not, how would InterMapper "know" which rows to process?
-       Do you ever need to relate data from one table with data in
another table?
-       Are there cases where you'd want to use data from one device to
retrieve a
value from another device?
-       What computations/calculations/comparisons would you expect the
probe to
perform?
-       Are there additional built-in functions that would help to
create the probe?
-       How should the tabular data be formatted in the status window?
-       What other facilities would you want to see?

We would be pleased to hear your thoughts. It would be great if you can
specify
certain equipment/MIB/OIDs/etc. that you're familiar with. It would
also be
useful to know about the "competition" - any other tools/programs that
offer a
good way to do these things. Many thanks!

Rich Brown                    [EMAIL PROTECTED] 
Dartware, LLC                 http://www.dartware.com 
10 Buck Road, PO Box 130      Telephone: 603-643-2268
Hanover, NH 03755-0130 USA    Fax: 603-643-2289

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