O'Reilly logo

CCNP Practical Studies: Troubleshooting by Donna L. Harrington

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Ethernet Frames

In Chapter 1, “Shooting Trouble,” you learned that the protocol data unit (PDU) for Layer 2 is frames. Frames refer to the entire message from Layer 2 to Layer 7. Control bits mark the beginning and end of frames just as picture frames mark the edges of a picture. Because you are already familiar with how Layer 2 allows different devices to take turns on the media (media access control), and how the network works (logical topologies), now I want you to look at how Ethernet data is actually packaged at Layer 2. In particular, compare DIX Ethernet to IEEE Ethernet, including the various Layer 2 headers in Figure 5-3.

Figure 5-3. Ethernet Frame Formats

Use Figure 5-3 and the Figure 5-4 flowchart as a guide to walk through the Ethernet ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required