用户手册
Cisco 9k系列设备支持sflow协议，请在配置模式下配置下面命令:
feature sflow // follow this for all the interface of the device.
sflow sampling-rate 4096
sflow max-sampled-size 256
sflow counter-poll-interval 60
sflow collector-ip {NFA server IP}
sflow collector-port 9996
sflow agent-ip {Any L3 interface IP}
sflow data-source interface {interface name}