I agree with your thoughts about separation of concerns. Unfortunately the data structure itself is defined in IETF RFC 2865 since 2000. For my application, the attribute-value pairs need to be extracted in real-time from RADIUS packets in an embedded network device under extreme load. In this case, the efficiencies of directly extracting the AVPs from RADIUS packets, without first creating an intermediate representation, may outweigh all other factors. I am thankful for all the replies to this post as they allowed me to expand my view of the problem and potential solutions. I plan to measure performance for all of the proposed solutions. I will choose the most elegant and maintainable solution that meets the performance requirements. Thanks again to everyone who put thought to my problem.