How does the sFlow Probe “Virtual Tap” technology work?
If you have one or more core switches that carry all the traffic to your routers, you can monitor all the traffic that crosses the switch(es) using an sFlow Probe attached to gigabit SPAN port(s) of the core switch(es). Since you are already seeing all the raw packets that go up to the router, there is no need to monitor the router too. With “Virtual Tap” monitoring, the sFlow Probe can extract routing information from the router and use that information to allocate traffic seen passing through the core switch(es) to remote the links (see drawing below).
