Although modularized protocol frameworks are flexible and adaptive to the 
increasing heterogeneity of networking environments, it remains a challenge to 
automatically compose communication stacks from protocol modules. The typical 
static classification into network layers or class hierarchies cannot 
appropriately accommodate cross-cutting changes such as overlay routing or 
cross-layer signaling. In this paper, we discuss how protocol composition can 
be driven by functionality and demand at runtime based on extensible semantic 
models of protocols and their execution environment. Such an approach allows 
to reason about the functionality and quality of automatically composed and 
adapted protocol compounds and it is open to existing and future protocols.