Progress Check: Completed Day 18 of the Complete CCNA Course by Jeremy’s IT Lab.

This past week especially has seen a significant increase in difficulty with regards to the content, especially as the learning begins to move away from what I have previously been taught in school.

I have learnt three major topics: routing, subnetting and virtual local area networks (or VLANs).

My previous blog post was an introductory guide to routing at Layer 3, but more than anything, the subject actually clarified my understanding of the differences between Layer 2 and Layer 3 of the OSI Model.

Prior to this, I had been following the textbook definitions of the model, and was able to regurgitate information to answer quizzes or assignments.

But now I can clearly define the life cycle of a packet.

At the Network layer (Layer 3), packets are encoded with the source IP address and the destination IP address so that the data has a clear pathway of where its final destination will be.

But at the Data Link layer (Layer 2), the Ethernet frames are continuously decoded and encoded at each step of the way, as the MAC addresses are updated to provide for its next hop.

In essence, the Network layer IP addresses dictate the data’s entire journey (from its original source to its final destination), whereas the Data Link layer MAC addresses provide step-by-step directions for the frame to travel.

Subnetting is also a fascinating subject to revisit.

Last year I was staring at binary digits and math equations and really struggled to get my head around the scenarios.

But thankfully, I was able to retain that knowledge and answer questions pretty easily this time around. I will endeavour to do regular subnetting practice every now and then so I don’t get rusty — to some extent, it’s maybe even a little fun.

So far, it seems that VLANs are probably the newest subject for me.

And judging by the content from the last few days, it is very likely to be a subject I will need to revise.

From a purely theoretical approach, I can understand how VLAN works as a way to separate a network into different smaller networks (i.e. for different departments in a corporate environment). I understand how it would be different from subnetting, and how VLANs and trunking will also require more unique network configurations.

But as some point I was overloaded with different interface numbers and CISCO commands and the rest of the content became a slight blur for me.

I suppose that’s how you’re supposed to learn. You’re thrown into the deep end with a subject you know nothing about, and slowly but surely you force yourself to make sense of things. Otherwise you might drown.

All in all, another productive week of study.

I wonder how long I can keep this momentum going, and if I will actually complete this course or just quit halfway.

But I suppose that’s what this blog is for. To hold myself accountable.