[e2e] Layering vs. modularization

[David P. Reed]

Joe Touch wrote:
>
>> The layering concept is a particularly narrow form of structuring.   
>> It implies that there is a single correct linear sequence for 
>> building up a complete functional system.
>
> It presumes only that there is a total ordering. Such ordering can 
> include branches and variations - only that any particular path has a 
> unique order.
>
Huh? I think you are describing a lattice or poset, which is called a 
Partial ordering, not Total.  Interesting, but not a "layering".

Youre describing a modular structure, not a layered architecture,