Exploring the encapsulation process

Now that we have gained an understanding of the layers, let's look at how each of the layers works together during the encapsulation process to create a frame.

During frame formation, the process begins with data. As the data moves down the layers, a header is added, one by one, until the frame is complete. Each frame has the following components:

• Data and an appropriate Application layer header (if applicable)
• A segment header
• A packet (or IP) header
• A frame header

We'll start with the data portion of the frame.

Viewing the data

In most cases, when frame formation begins and encapsulation takes place, we start with the data, as shown here:

Figure 8.6 – The encapsulation process—data

The data might be any of the following:

• An HTTP GET request
• A DNS request to resolve a hostname to an IP address
• A DHCP broadcast to request a dynamically assigned IP...