You can perform ZyXEL Appliance configuration using the following steps:
configure terminal
sflow
sflow collector {NETFLOW_SERVER_IP} udp-port {NETFLOW_SERVER_LISTENER_PORT}
Enter global configuration mode on the router or MSFC, and issue the following commands for each interface on which you want to enable flow:
interface {INTERFACE_NAME}
sflow collector {NETFLOW_SERVER_IP} poll-interval 60 sampling-rate 256
exit