To be successful with modelling a device you need a few things before you start.
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Device Modelling Preparation
Device Access
You can model a device without having one, but it is REALLY HARD, having SNMP readonly access to a device is vital for success.
SNMP MIBS
You will need to have all the necessary standard (IETF/IEEE) MIBs and the vendor specific MIBs for the device to be modelled.
SNMPWALK (SNMP Dump)
Once you have the MIBs the best way to interpret the MIBs is to complete an SNMP WALK of the device, first verify that you can use SNMP to access the device see the following article: Testing SNMP Connectivity from the NMIS Server with snmpwalk
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Now you have an SNMP Dump.
Goal for Modelling
What is the goal for the modelling? Just standard type support, or more advanced collection, do you want to collect some performance data about how a protocol is operating, or verify the number of sessions a firewall is running.
Sometimes you can find the source MIB in the documentation or a whitepaper, but sometimes it is very difficult to determine where the needed data is stored. If possible ask a product expert who is familiar with that specific product.
Device Instrumentation
Many times, people want to graph CPU and Memory, but not all devices support the collection of this information, you can only ask NMIS to collect something which the device has the instrumentation for, the MIBs should tell you if it is possible.
Relevance of Instrumentation
For Cisco routers, it is very handy to monitor CPU load, it is an excellent metric for how the device is performing, however on some newer Cisco devices, the processing is distributed and performed in hardware, so the CPU load is still handy but it may not be providing the information you need.
Verify the MIB Operation
Now you know what you want to collect and monitor, verify that the MIB operates the way the documentation says it does and verify that it works they way you think it does.
Techniques for Modelling
Now you know what you want to model, you will need to decide to use the system or systemHealth techniques for having NMIS collect and store the data, you will also want to decide if you want any custom alarms configured.
This page has great information about Modelling MIBS that use Indexes using the systemHealth section.
Developing Device Models for NMIS
Checkout the handy training we developed for NMIS users, this is available here:
Checklist for Model Development
The training covers this in details, but here is a quick summary of what needs to be updated and changed when adding new device support with modelling
- Update nmis8/models/Model.nmis
- New model file created and updated
- update the nodeVendor, nodeModel, nodeType fields (among others)
- Any new resolvable OID's added to nmis_oids.nmis, e.g. the sysObjectID names.
- Update Common-heading.nmis
- Update Common-database.nmis
- Create any needed graphs
- Update Common-threshold.nmis
- Update Common-stats.nmis