However, I had issues just enabling this and assuming it worked on my switch. I could never get my SNMPv3 monitor to connect. So, I dove into the CLI. If you want to know how to get to the CLI in Unifi USW switches, see my other forum post here: CLI enable on Unifi USW.

Configure the switch side SNMP

View your current configuration:

show snmp
show snmp engineID
show snmp group
show snmp user

Now, here are the commands that worked for me:

configure
snmp-server v3-host 10.1.149.51 yoursnmpuser traps priv
exit
write memory

Configure the switch side sFlow

configure
sflow receiver 1 owner mysnmpname 10.1.149.51 6343 2000000 2

This sets up an sflow receiver with in slot 1, owner is a friendly name you can set, IP is the SNMP monitoring server, port 6343, max datagram size is 2000000, timeout is 2.

Set the ports that will be enabled for sflow

sflow source-interface network

interface 0/1-0/52
sflow sampler 1
sflow sampler rate 4096
sflow poller 1
sflow poller interval 20
exit

##Save configuration##

exit
write memory

## Verify

show sflow receivers
show sflow samplers
show sflow pollers
show sflow agent

Important notes on the SNMP version

In the "new" UI in the Unifi network application, they don't show you what the encryption and authentication methods are. However, I can confirm those are the following:

- SNMP Version: v3
- Authentication Method: SHA (not MD5!)
- Encryption Type: AES (not DES)

Hopefully, these notes will help anyone else who is struggling to get SNMPv3 up and working on a Unifi USW enterprise network switch.