SNMP Bulk Walking

In the prior topic SNMP Walking was described whereby the next sequential OID is fetched in each inquiry. This is the best one can do when SNMP walking any device that only supports SNMP version 1. However, should a device support SNMP version 2c then you can use Bulk Get whereby any number of sequential objects can be read in each inquiry. Whereas a single device contain THOUSANDS of objects, being able to read 50 or more objects at a time can reduce the number of transactions 50 fold more!

Open the same panels as for SNMP fetching:

• MIB Tree panel
• SNMP Fetch panel
• Message Log panel
• Message Content panel

Alternately, simply select and load the SNMP Fetch workspace. ScanEngine Explorer comes with a collection of pre-configured workspaces which included one called SNMP Fetch with an arrangement of MIB Tree, SNMP Fetch, Message Log, and Message Content panels.

To interrogate an object by SNMP, enter target info on the SNMP Fetch panel

• Target IP
• Timeout
• SNMP Ver
• Community String
• Select the first OID in the tree
  • Add the first object appearing in the MIB Tree.
  • Clicked objects will either be added or removed according to the check/uncheck control on the MIB Tree or Table.
  • If necessary, clear all prior object/suffix/value items with one click of the clear button on the SNMP Fetch panel.
• Enter 0 for Non-Repeaters
• Enter 20 for Max-Repetitions
  Try larger numbers to read even more objects per transaction

Click the Bulk Get button on the SNMP Fetch panel sends the inquiry, and the inquiry appears in the message log panel.

Either the target will reply, with the reply appearing in the message log panel and the content of the reply appearing in the message content panel, or a timeout will occur should no reply be received within the specified timeout interval.

If the target replied, the reply contains the 20 objects that immediately followed the object from the request. Reclicking the Bulk Get button would simply repeat the previous request for the same objects. Rather than manually changing the selection to the next object from the Tree, subsequent Bulk Get requests can automatically be sent with the last OID received by using the SNMP Bulk Walk button. Each press of the SNMP Bulk Walk button will request the Bulk Get sequential following the last object received in the prior Bulk Get.

Notes:

• How large can Max-Repetitions be set, or how many objects can be read at a time in a Bulk Get, or SNMP Bulk Walk? SNMP objects vary in size, so there is no simple answer. SNMP transactions are limited to a single packet each, so how many objects can fit in a single response packet depends upon how large the requested objects are.