NehaManoj

An exercise of expression!

Standards, Encapsulation & Decapsulation

What happens when you walk into a room of people who understand only English and start speaking in Telugu?
Answer: They give you the worst looks possible and probably will kick you out.

standards wordcloudToday, I started training a cohort of new hires at Cisco on CCNA Routing & Switching. The benefit of being the trainer – I did not get kicked out – but I got the dirty looks for sure. Why did I do that? I had no better way of explaining the importance of standards and protocols in computer networks. One of the fundamental aspects of how communication works is standards and protocols. Two devices that want to talk to each other, need to agree upon a common language or a standard. Everything else will follow.

Standards & Protocols

In my 6 years of working with network engineers, both inside Cisco and Customers alike, this is one of most important aspect that gets missed out. A lot of times, engineers understand a particular concept and feed it to their brain in their own way. And once the troubleshooting starts, they believe that a certain functionality should be working, but it doesn’t. In most cases, the answer is that either the packet is missing a flag in its header, or the device is not configured (hardware/software) to process that information the way it is outlined in the standards. I only tell them one thing, think from the device point of view and not by your feelings. It is that simple. If we look at the protocol standard and what is expected from the device, we know why something is working or not, or at the least the direction to look.

Encapsulation & Decapsulation

One other fundamental aspect that I covered today is about encapsulation and decapsulation.  We all know that data gets encapsulated at source when it moves from Application to the Data link layer in the TCP/IP stack and then decapsulated when it reaches the destination. However, after the CCNA course, no one gives as much importance to this concept as it deserves. Most new protocols that we can think of in traditional networks came into existence because of encapsulation. VxLAN, OTV, MPLS and what not. Each of these protocols work on the basis of a small header encapsulation on an existing packet. If we can abstract our understanding in these lines – at what point in the network a packet gets encapsulated, and at what point does it get decapsulated, we can clearly see how the protocol is working.

In essence, the key two takeaways from today’s session – Standards/Protocols, Encapsulation/Decapsulation. If you know this, you know everything 🙂

What do you think?

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