Get “top” OID for given MIB

Question

I want to get the top "OID" for a given MIB. i.e;

CISCO-SMI = 1.3.6.1.4.1.9

CISCO-PROCESS-MIB = 1.3.6.1.4.1.9.9.109

I can easily get this by googling, however I need to get this from a system, preferably with native SNMP commands. I can't walk a device. I can do an snmptranslate which will give me all OIDs for that MIB, but I only want the OID that identifies the MIB;

snmptranslate -Tso -m /usr/share/snmp/mibs/CISCO-PROCESS-MIB.txt

.1.3 .iso.org

...

.1.3.6.1.4.1.9 .iso.org.dod.internet.private.enterprises.cisco

...

.1.3.6.1.4.1.9.9.109 .iso.org.dod.internet.private.enterprises.cisco.ciscoMgmt.ciscoProcessMIB

So I need to be able to say that CISCO-PROCESS-MIB = .1.3.6.1.4.1.9.9.109

I've done a fair bit of google-fu but not coming up with anything that gives me the above. Is it possible to do without an external mib browsing tool?

A MIB document can have no such "top" OID and still be valid (read SMI specifications), so it is generally a bad idea to rely on it. Why do you want to do that? — Lex Li
I wanted to write a script to determine OID which relates to the MIB. A better way might be to explain the "highest level" OID which is translatable by a given MIB. — ClontarfX
A MIB compiler/parser would easily tell which OID belongs to which MIB document, so your "hack" is meaningless. Only certain MIB documents follow the convention you prefer so that you might find a "top" OID, while other MIB documents do not follow that, and they can define any OID pattern they like. If you don't like "external MIB browsing tool", then your script has to do exactly the same work, and I wonder if you are more capable than any of the vendors (disclaimer: I am one of the vendors). — Lex Li

Gambit Support Gambit Support · Accepted Answer · 2018-04-19T15:01:16

The set of all SNMP OIDs can be expressed in a tree, of which a particular MIB file defines a (possibly empty) sub-forest with leaf nodes (actual MIB OBJECTs). Ie. a MIB file defines a set of sub-trees. If you are lucky, the set of sub-trees starts at a single node, and no other MIB defines OIDs under that node.

Given this background, in MIMIC SNMP Simulator we define a TOPOID as the lowest (in the hierarchy) OID that contains all the OIDs defined in the MIB. In MIMIC we maintain the set of OIDs for all the MIBs that the simulator knows about, so that you can quickly determine from an arbitrary leaf OID which MIB it is in (by finding the lowest TOPOID in the hierarchy), eg.

% ./oidinfo 1.3.6.1.4.1.9.9.109
INFO  04/19.10:58:34 - OID 1.3.6.1.4.1.9.9.109 = ciscoProcessMIB
INFO  04/19.10:58:34 - MIB = cisco/CISCO-PROCESS-MIB
...

Get “top” OID for given MIB

1 Answers