The previous generation of the QNX Neutrino networking stack ( io-net ) was designed based on a modular approach. It served its purpose in the past by allowing users to separate protocols and drivers, but this came at the expense of incurring a significant amount of overhead when converting to a particular protocol's domain from io-net and vice versa.
Note that io-pkt and the new utilities and daemons aren't backward-compatible with io-net.
Figure 1. Changes to the networking stack.