To enable sFlow v5 on Juniper EX or QFX you need to apply initial configuration for sFlow v5 agent on switch:
set protocols sflow polling-interval 30 set protocols sflow sample-rate ingress 1000 set protocols sflow sample-rate egress 1000 set protocols sflow source-ip [Local IP to send sFlow from your switch] set protocols sflow collector [FastNetMon IP] udp-port 6343
Please note that EX and QFX switches allow you to configure multiple collectors
Then you need to enable sFlow protocol for interfaces facing your upstreams:
set protocols sflow interfaces et-0/0/xxx set protocols sflow interfaces et-0/0/yyy
To ensure that configuration is correct we recommend checking sFlow agent configuration:
show sflow sFlow : Enabled Adaptive fallback : Disabled Sample limit : 300 packets/second Sample limit threshold : 150 packets/second Polling interval : 30 second Sample rate egress : 1:1000: Enabled Sample rate ingress : 1:1000: Enabled Agent ID : ... Source IP address : ...
And then we recommend checking per interface configuration which looks this way on EX platforms:
show sflow interface
Interface Status Sample rate Adapted sample rate Polling-interval
Egress Ingress Egress Ingress Egress Ingress
ge-0/0/0.0 Enabled Enabled 1000 1000 1000 1000 30
On QFX it looks different way:
show sflow interface
Interface Status Sample rate Adapted sample rate Polling-interval
Egress Ingress Egress Ingress Egress Ingress
ge-0/0/13.0 Enabled Enabled 1000 1000 1000 1000 30
ge-1/0/15.0 Enabled Enabled 1000 1000 1000 1000 30
ge-1/0/20.0 Enabled Enabled 1000 1000 1000 1000 30
ge-1/0/21.0 Enabled Enabled 1000 1000 1000 1000 30
For more detailed information please check official vendor documentation