SNMP is an old time workhorse of information. If you’ve been a network engineer for a while, the ability to automatically discover objects when you’re documenting […]

How Does Automatic Network Mapping Work?

SNMP is an old time workhorse of information. If you’ve been a network engineer for a while, the ability to automatically discover objects when you’re documenting […]

Logical map in netTerrainSNMP is an old time workhorse of information.

If you’ve been a network engineer for a while, the ability to automatically discover objects when you’re documenting the network can’t be overhyped. Automatic network mapping, on this level, significantly reduces your manual workload and ensures that your documentation is accurate and up-to-date.

If you’re looking at documentation software, you may hear the terms ‘snmp’ and ‘mib’ thrown around. We use them for automation in both our data center management software and automated network documentation software (the netTerrain suite). To fully understand the capacity of automated network mapping, let’s go over how it works.

So, what is SNMP? Let’ s start with the (fun) facts:

“SNMP is widely used in network management for network monitoring. SNMP exposes management data in the form of variables on the managed systems organized in a management information base (MIB) which describe the system status and configuration. These variables can then be remotely queried (and, in some circumstances, manipulated) by managing applications.”

Thanks, Wikipedia: so, are you fully informed and ready to go now?

What can SNMP do for network mapping?

To start, we can use it as a means of discovering objects on the network…and by that, I mean more than just a simple response to a ping where you may get a “hey, i’m on and over here”.

With SNMP, we can determine what the device is and then use that information to create the object in a diagram — 100% automatically. SNMP is full of great information that you can poll and grab on a regular basis.

SNMP works…thanks to the MIB. What’s the MIB?

According to Wikipedia, “A management information base (MIB) is a database used for managing the entities in a communication network. Most often associated with the Simple Network Management Protocol (SNMP), the term is also used more generically in contexts such as in OSI/ISO Network management model. While intended to refer to the complete collection of management information available on an entity, it is often used to refer to a particular subset, more correctly referred to as MIB-module.

Objects in the MIB are defined using a subset of Abstract Syntax Notation One (ASN.1) called “Structure of Management Information Version 2 (SMIv2)” RFC 2578. The software that performs the parsing is a MIB compiler.

The database is hierarchical (tree-structured) and each entry is addressed through an object identifier (OID). Internet documentation RFCs discuss MIBs, notably RFC 1155, “Structure and Identification of Management Information for TCP/IP based internets”, and its two companions, RFC 1213, “Management Information Base for Network Management of TCP/IP-based internets”, and RFC 1157, “A Simple Network Management Protocol”.

So, really, you have a device with a database of information that is just waiting to be interrogated.

Now…there are details about the device that are part of the open standards and you can also find device/vendor specific information as well. So….maybe you want to know not just what the device is but how many ports are active or what is the power draw or maybe some temperature value? Typically, this can often be accomplished by grabbing data from the MIB via SNMP.

Back to documentation…how does all of this help you?

You can use a tool to find what’s on the network and automatically gather information about those devices. You can use a tool to find exactly what is on the network and to get information about the devices that are on the network. In some cases (for example, with netTerrain), you can even get information about how the devices are connected together on the network.

Jason Sherman
Jason Sherman
As Graphical Networks’ Sales Engineering and Support Services Manager, Jason Sherman leads the pre and post sales cycle with the entire Graphical Networks software portfolio, and ensures current customers are able to use the software to its fullest potential.

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