Router hardware design guide, where i can get help??

hi everyone,
    i am a beginner for this ietf. i am now interested in router hardware 
design, but i need help.

    for example, i am now going to implement a NAT router, for better 
performance, i have to use ASICs in the router as more as possable. then, how 
can i design a router which will be both best performance and scalable for the 
futrue?? is there any information such as design-check-lists i can get form the 
Internet?? Thank you for your help.

    Thank you very much!