When I first started in IT Security I had an okay but not expert knowledge of how server operating systems work with TCP/IP stacks, nor was I an expert in TCP/IP on the wire. I thought that it was unnecessary and that I wouldn't gain much from learning it.
Years later, now being intimately familiar with server TCP/IP stacks and TCP/IP on the wire, I can tell you that I understand what is going on exponentially better, and I am much faster at detecting anomalies and understanding new security threats. Yes, even at a software level.
However, when cutting into IT security my suggestion is you will typically not actually understand the security concerns unless you have the ability to configure the boxes as an admin. This means time in the trenches as an operations or admin employee.
So, while I would agree that a knowledge of TCP/IP is very important, you should also know that to actually grasp the entire IT Security field you must have advanced knowledge in a plethora of IT concentrations.
IT Security is a never-ending learning experience, similar to all IT concentrations. However, since Security is broad you need to be aware of the changes for ALL IT concentrations, which is what makes this field challenging (And why I went into it). You will deal with new technology and new threats constantly, and if you are unable to dedicate yourself to keeping up with the field, you will no longer be effective in your job.
That being said, I feel that it's a great place for academics such as yourself because the perpetual learning process is not new to you, and academics also are comfortable "deep diving" numerous technologies.