Enterprise MIBs
Why?
With all these MIBs, why do vendors need to write their own, non-standard ones? I mentioned in a previous chapter that a vendor might want to provide features unique to its products. Standard IETF (Internet Engineering Task Force) MIBs are intended to represent the core features of a particular technology - what every router, switch, printer, etc. would have. But each vendor's products are likely to have additional manageable features.
Enterprise OID
The vendor-specific MIBs, or Enterprise MIBs, would be situated under the enterprises subtree, the node for which we saw in the Management Information Tree (or in your MIB browswer), whose OID is 1.3.6.1.4.1. Each vendor that wants to define a MIB must get a Private Enterprise Number (PEN), which is obtained from IANA. You can see the list of Private Enterprise Numbers (which, since there are thousands, takes a long time to load). You can even find our sponsor ( RAD Data Communications, of course) at number 164. So RAD's OID is 1.3.6.1.4.1.164.
Sample Enterprise MIB
Guess which company I selected in order to show a sample of an enterprise MIB! I'll give you three hints: they sponsor this great website, they are my employer, and they make great products. Bingo!
It's a simple sample - appropriate for the protocol name. That's because an actual MIB for a RAD product has many dependencies and you'd have to import close to a dozen other MIBs, and then, aside from importing those MIBs, you'd have to wrestle with the compiler in Blackowl - the compiler complains about things that it shouldn't. Anyway, an actual MIB has many more details than you would really care to look at. So, I took a teeny-tiny subset of a RAD MIB and adjusted it so the compiler won't complain. You can import RADDEMO-MIB.txt, load it, and then switch to the tree view. Your tree view should look like Figure 40.
Figure 40: Demo RAD Enterprise MIB
You can see how the demo MIB is located at 1.3.6.1.4.1.164. You can also see that RAD defined groups under that for various product families, such as WAN products (the first node under raddemo) and ATM products (the last node under raddemo). radgen is the node in this teeny-tiny demo MIB that actually contains a few objects - it is a group for general objects that apply to all products. If you'd like to look at the definitions of the objects, just take a look at the RADDEMO-MIB.txttext that you just imported. It gives you just a glimpse of the types of objects that a vendor might decide to define to supplement the standard MIBs.
In the next chapters, we'll look at SNMP messages - how do we actually get to read and/or modify all the management information defined by the numerous MIBs that you've become familiar with.
