SnmpCollect adjust the number of MIB-Variables in response to
unsuccessful collects from the agent machine. You can see it in messages
which appear in the snmpCol.trace
At start:
Host Information:
#1 gipsi.ikossvan.de SNMP to 192.168.41.4 stored as 192.168.41.4
maxObjPerPDU:40
Next collection configuration check in 23.97h
Later adjusting:
< i have no example available>
If you activates the snmpd-trace you can analyze the PDUs and check
the size or the number of mib variables.
W. Klein
============================================================================
======
Date: Wed, 19 Sep 2001 23:30:17 -0400
From: "Leslie Clark" <lclark@us.ibm.com>
Subject: RE: Netview PDU Packing Question
I may be getting in over my head, but then again this may be
a clue. In Netview for Unix at any rate, the snmpCollect parameter
that Oliver refers to defaults to 100. This is not about size, it is
about the number of requests that it will pack together. I think.
With
current devices with large numbers of interfaces I have found
lately that I sometimes have to reduce that (say to 50) to get the
request down small enough that the device is able to answer.
So I would say yes, snmpCollect is packing. By reducing the limit
I believe that I am forcing snmpCollect to make more than one trip
to the device, so the device can answer within the timeout allotted
without error. If I am collecting two or three variables from all
instances
in the interface table, this quickly gets too big and the get fails.
With
it set to 50, the get succeeds because the device I am polling can
handle it without choking.
Cordially,
Leslie A. Clark
IBM Global Services - Systems Mgmt & Networking
Detroit
"Paul Maine
Jr." To: "'IBM NetView
Discussion'"
<paulm@msicc.c <nv-l@tkg.com>
om> cc:
Sent by: Subject: RE: [NV-L]
Netview PDU
owner-nv-l@tkg Packing Question
.com
09/19/01 12:04
PM
Please respond
to IBM NetView
Discussion
I have Netview NT and your suggested method does not appear to work
for NT
-
is there another means to set this for NT?
Thank You
Paul
-----Original Message-----
From: Oliver Bruchhaeuser [mailto:oliver.bruchhaeuser@de.ibm.com]
Sent: Wednesday, September 19, 2001 10:48 AM
To: IBM NetView Discussion
Subject: RE: [NV-L] Netview PDU Packing Question
Hi,
there is an option for snmpCollect:
-m MaxMibPerPdu
Collects values for the maximum number of MIB variables that
can be
requested for a PDU. To find out the default value, issue the
command
snmpCollect ?.
Take a look at "man snmpCollect"
Kind regards
Oliver Bruchhaeuser
"Allison,
Jason To: "'IBM NetView
Discussion'"
<nv-l@tkg.com>
(JALLISON)" cc:
<JALLISON@arin Subject: RE: [NV-L]
Netview
PDU
Packing Question
c.com>
Sent by:
owner-nv-l@tkg
.com
19.09.2001
16:53
Please respond
to IBM NetView
Discussion
FWIW, my response is from an application program perspective.
How are you looking to perform this request? With respect to the
PDU as
declred in OVsnmpApi.h:
#define PDU_SIZE (sizeof (OVsnmpPdu))
The PDU structure is only bounded by your memory contraints. You
could
declare a PDU with as many oids as you desire using 'OVsnmpVarBind
*variables'.
When you talk about 1500 bytes are you referring to ethernet packet
size?
At the application layer multiple packets should have been
re-assembled to
give you your entire request.
Hope this helps,
Jason Allison
Network Engineer
ARINC Corporation
Annapolis, MD
-----Original Message-----
From: Paul Maine Jr. [mailto:paulm@msicc.com]
Sent: Wednesday, September 19, 2001 10:37 AM
To: Netview List (E-mail)
Subject: [NV-L] Netview PDU Packing Question
My question relates to the efficiency of how Netview performs SNMP
GetRequests during collection. I am aware that most SNMP agents
today
support a maximum Protocol Data Unit (PDU) of 1500 bytes. Does
Netview
support a PDU size of 1500 bytes?
If I enable Netview to collect 10 different MIB objects, will the
SNMP
GetRequest include all 10 of the MIB objects in a single PDU or will
Netview
use 10 separate requests to obtain the information?
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