Only for bandwidth, you can use MRTG. You can also copy all the trafic to a probe and use NTOPNG to have a dashboard with also the protocols flows and other IP data.

@Darryl Theron What experience do you have with this tool? I'm looking for NCM alternative for a medium size network (3000 network devices like routers and switches. And what about this german company?

@reviewer1140534 What experience do you have with this tool? I'm looking for NCM alternative for a medium size network (3000 network devices like routers and switches)

PRTG is a nice tool to monitor performances of a wide kind of network devices. This tool is based on SNMP requests, and it is very easy of use

Why not? What are this advantages?

It actually depends on the exact purpose or kind of devices (network devices, servers, something else). Some tools are better for only network devices while others are better for a cloud monitoring or APM monitoring It is easy to survey basic topics with only one tool…

You can use the IP SLA feature running on Cisco routers. As so, you can define many protocols to monitoring. You have to confogure a router as IP SLA sender and many routers or devices as IP SLA responders. Depending of the feautures of the responders, you can see ICMP, UDP…