I am speaking about the PDU packing capabilities of the standard Netview
collections that are setup through the standard collection GUI ( i.e. no API
calls at this time ).
The source for the 1500 bytes is a book entitled "Troubleshooting with SNMP
& Analyzing MIBs" by Louis A. Steinberg. The book makes a statement the most
SNMP agents supports a maximum PDU size of 1500 bytes before reporting a PDU
error status of "Too Big". If the "Too Big" error status is returned, the
message will be fragmented.
In the interests of efficiency and scalability, most of the devices I
monitor would have a variable binding list that would easily fit in one 1500
byte PDU or less. If Netview uses PDU packing, the polling could be very
efficient.
I should also point out that we are using Netview NT.
Thank You
Paul
-----Original Message-----
From: Allison, Jason (JALLISON) [mailto:JALLISON@arinc.com]
Sent: Wednesday, September 19, 2001 9:53 AM
To: 'IBM NetView Discussion'
Subject: RE: [NV-L] Netview PDU Packing Question
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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