NTP firewall works/scans packets on which Layer

I wanted to know,

NTP firewall works/scans packets on which Layer?

NTP is which type of firewall?

how & when IPS integrated with NTP?

How & when IPS scans files

How & when AV/AS scans files

How & when SONAR scans files

if I select 1 file which AV feature scans first & then which one scans it.. what is hierarchy...