amazon web services - At what OSI layer do AWS Network Access Control List operate?

Question

I've read couple of articles about AWS Network Access Control Lists (NACLS):

• Network ACLs
• Internetwork traffic privacy in Amazon VPC

Those articles do not mention at which OSI layer NACLs work. Maybe someone can help me understand at which OSI layer they operate?

Answer 1

Network Layer

As a packet comes to the subnet, NACL evaluate it against the inbound rules of the ACL that the subnet is associated with it.

In OSI layer, Packets are handled in Network Layer Only. or

Data Unit of Network Layer is Packets and subnet evaluates Packets.. 

so it is Network Layer