A way to check what is using up Network Bandwidth

I suspect its a docker image that was miss behaving… but it Raised a question… Is there a way to check who or what is utilizing the network bandwidth ?

After upgrading to much anticipated 7.2 and docker / central manager so I could install my Omada network controller. I suspect my ds220+ didn’t quiet have enough memory to run it well. So I had to shutdown the controller. (And migrate back to Raspberry Pi) Since then I have been seeing 1 Mb worth of network activity hitting the NAS. And consistent 70% memory usage. Even though the docker project has been shutdown.

I suspect the network activity might be related to one of my network devices hitting the NAS as the control failed to readopt the device.

Trying a reboot of the NAs to see if that will clear things out…

So really three question…

1 - Is there an easy way to track who utilizing the memory & bandwidth.
2 - Can the ds220 + run docker image well enough with out expanding the memory?
2.1 - any recommended memory kits to expand the devices ram. (reasonably priced)
3 - any known gotchas I should watch out for when using the NAS as my network controller? Very similar to what Will mentioned in one of his vides for ubiquity controller. The NAs has a number of activities on going … Usual 3,2,1 backups with hyper backup, Drive / lightroom fun and backup for business backing a few PC & Raspberry Pi

if you install a community package called SynoCLI Monitor Tools, you can ssh in and run bandwhich to identify your traffic.

I have a post on how to install community packages here: SynoCommunity packages