The snmp4netlib library is simple to use and has a lot of functionality. It provides great support for SNMPv1/v2c/v3 as well as extended MIBs like CISCO-OSPF etc. I have used this in some projects at work which needed monitoring of the network devices via snmp. This has provided me with a good insight into what devices are up and down. The documentation could be better. There are a few points here and there where you need to go through the source code or look up other resources online (or even ask on StackOverflow). If your looking to implement an application that monitors the network devices then this would be one option. We were using it to do just that. It was running across our network switches and routers and providing us with information regarding.