CCNA Module 8: Network Layer - Introduction to Networks (ITN)

[@nheiltowers5022]

Hello sir! Great lesson! Although I am a bit confused at 43:38. What is an exit interface? I tried researching about what an interface is and backtracked on the previous lessons and you only explained briefly about interfaces and ports at Module 2 but Im still confused of its vague definition 🥲 I'd love an explanation on what it is exactly, thank you sir for your free lessons.

[@NetITGeeks]

Good question! The terms "exit interface" and "entrance interface" are often used by instructors and IT professionals to describe how a packet "move" through a network across devices. In this example, the "exit" here refer to where the packet moves out of the router. Exit and entrance ports on the other hand are used to describe physical ports on the networking device. If you have VLANs or virtual interfaces, they can be attached to a single physical port. But from the switching and routing perspective, what we really care is the interfaces not the port itself. For example, if a packet is entering from interface VLAN10 and being routed to VLAN20, the VLAN10 and VLAN20 are interfaces not ports because VLAN10 may be on port 5 and VLAN 3 could also be on the same port 5. However, the packet never sees the VLAN 3 because the entrance or exit interface is VLAN 10. Is that makes sense?

[@nheiltowers5022]

@@NetITGeeks Oh yes, thank you! It makes much more sense now! I'm just confused since ports and interfaces are often interchanged so I am just trying my best to understand. From what I understand, a port could be the physical connections of a network while interface is more of a virtual version of that. Got it. Thank you again sir! 😁