Hi , I have use sflow to monitor my device, and found two things：
1.I cannot get bandwidth if the traffic is thought GRE tunnel.
2.The bandwidth information seem not inaccurate, I have compare with device interface and another flow collect software(NetFlow Analyzer by ManageEngine), the bandwidth volume of PRTG seem always more then about 10M, I also have add filter by inboundinterface ,outboundinterface and IP address.
May I know how can I get bandwidth with GRE encapsulation ? and how can I add filter for specific IP and interface let the bandwidth volume more accurate ?