Ever wonder what the difference is between the CEF table and the Adjacency Table?
What is the default behavior for IOS if CEF is not enabled?
What is the difference between CEF and dCEF?
I got to read this book this week, and it is great for anyone who want to know more about the in-depth logic and guts of the IOS software. Some really great explanations here that outline the differences between Process Switching, Fast Switching, Optimum Switching, and CEF. It has some great graphics (flow charts mostly) to explain Load Sharing within CEF, and many other concepts. It explains how to troubleshoot CPU problems, and how they occur within the platform.
Personally, I found the most interesting parts where the author explains logical steps of different features native to the IOS platform. These are basically spread all around the platform, but particularly relevant are CEF and Fast Switching and how they are done in detail. The book also covers hardware architectures, I/O Memory, and gives insight into interpreting the output of "show diag", "show proc", "show interface stat", "show controllers", and other hardware-related diagnostic tools.
It also has a really good chapter on QoS where the author outlines queueing logic, different QoS technologies and how they are relevant to hardware, and finishes with NetFlow.
While the hardware platforms focused on in this book were aggregation-layer devices like the 7200 series routers, it would have been nice to read about the 3560 (which has powerful queueing architectures) and the 6500 series switches for example. Also, the material is a bit old, but valid nonetheless (don't expect to find anything on NX-OS or MPLS/Label Switching!)
You can buy the book from Amazon here
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