Not all routers and switches support NetFlow. For example, only certain models of Cisco equipment provide NetFlow data; many other manufacturer's gear will not export NetFlow records, either. If you use non-NetFlow capable equipment, there are a few alternatives/workarounds:

  • * Use a software exporter on a span or mirror port of a switch. If you have a managed switch, you can usually configure it to send all the traffic to a single span or mirror port. You can then install a software exporter on a computer and attach it to the span port. The software exporter will then send flow records to your NetFlow collector (such as InterMapper Flows).

    * Use a software exporter attached to a hub port. If you don't have a managed switch, you can still monitor NetFlow data by placing an unmanaged hub (not a switch) in the link whose traffic you want to monitor. For example, you might install the hub between your external router and your backbone equipment. The hub will pass all the traffic that flows through the link to the software exporter, as described above.

    * Use sFlow. Many prominent router and switch manufacturers (such as HP, Foundry, Extreme, Force10, and others) instead support the sFlow (sampled flow) protocol (link). Their equipment sends a copy of the header of one-in-N packets to an sFlow collector, which then performs much the same processing as a NetFlow collector. Watch this blog for information about an upcoming release of InterMapper Flows that handles sFlow.