Before we continue into interfaces and later on policies we need to understand one key concept.
Traffic flows in two directions.
Whenever a traffic is destined to our 48 that is it is destined towards an ingress interface.
Whenever a traffic is leaving our 40 gate.
Then it is destined towards an egress interface.
So if we have for example a marketing lan that is connected to our 48 through Port one interface and
is destined to the Internet through when one interface then our port one is the ingress interface and
our when one is the egress interface.