1.configure sflow agent ip (switch的管理IP)
2.configure sflow collertor ipaddress 192.168.X.X ports 9996 vr vr-default (收集sflow的伺服器IP及port，port number可自訂，預設為6343)
3.enable sflow (啟用sflow)
4.enable sflow ports all (啟用PORT)
5.configure sflow samlpe-rate 256 (採集率越小準度越高)
