Understanding SNMP and the configuration file

Question

I'm trying to get my head around how SNMP works and the configuration files.

From my understanding of how SNMP works so far is as follows: * Management Station - this manages the nodes (get/set are few commands the manager can perform) * Managed Nodes - These are the systems being managed such as SNMP capable switches, router and systems. * MIB - This is the database containing information about managed resources and services the SNMP agent supports

When a agent is added to the manager's domain, it must provide MIB information to manager. That way, the manager knows what features are available for the managed resource. MIB is a collection of information and are identified by object identifiers.

Does this mean object/value pairs (the variable binding) in SNMP PDUs are the OID of the objects and value of that object?

Also with the MIB database, how are they created? I'm assuming certain devices such as SNMP capable switches and routers, the MIB database is created by the vendor i.e. They'll compile the MBI module, set all the feature support by the device and generated an MIB database based on these features. Is this correct?

Does this also mean I'll need to create my own MIB database for a Linux or Windows managed node? Thank you in advance.

Answer 1

1) Yes, the object/value pairs in the PDUs are the OID and values.

2) MIBs typically split up into lots of chunks, each describing a different part of the tree. The management server will have a whole pile of MIBs, from the built in base ones defined in various RFCs, to any additional ones you supply from specific vendors you're interested in. It can then use this big tree of data when interacting with the managed nodes to interpret the data it receives back. It's worth noting here that it's possible to "walk" the OID tree of a managed node and get all the availale data back, even if you don't have the MIB. You may not then have any idea what the data means (the OID doesn't give any clues), but you'll be able to see it all.