Because network communication is expected to be an integral component of C0PE, a natural standard for analysis is the network. A typical analysis would be of the form, ``Can all devices on a IrDA network sustain encryption at that bandwidth i.e at 115 Kbps ?. If encryption can keep up with the network, use much less power, much less chip space and cost much less than the network, then universal encryption makes sense. Otherwise, the sophisticated knobs would seem necessary.
It must be noted that the level of security attainable is not an issue to be considered. This is because we are essentially studying the feasibility of ``strong'' encryption. Also, as seen from [Schneier99], most proposed strategies for AES, the future standard for encryption seem to perform independantly of the key lengths used. Hence, we believe that security is really a second-order concern.