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?
Thank You
Paul
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